Is Psychology a
Science?
What is
science?
According to
BF Skinner (1980), ‘there is no place in a scientific study of behaviour
for a mind or self’. But, pick up any A-level psychology text and it
will be described as the study of mind and behaviour; often in the
title.
Others go
further and believe that even an observable characteristic such as
behaviour cannot be studied objectively and certainly not when it’s
human behaviour.
To what
extent therefore can psychology claim to be a science?
Modern
definitions of science
Recent
attempts to define what makes science scientific have generally included
the following characteristics:
1.
Controlled observations
Generally in
scientific research something (the IV) is manipulated and we observe the
effect this has on something else (the DV). A physicist might
manipulate the weight of a pendulum and measure its period, whilst
obviously keeping length of string and height of release constant.
In
psychology this characteristic is best exemplified by the laboratory
experiment where as many variable as possible are kept constant to see
if the IV is causing the DV.
2.
Objectivity
Physics and
chemistry are objective and hopefully mostly free of personal opinions
but is psychology? Popper demonstrated this to an audience of
students. He said ‘observe.’ After a pause the reply was ‘observe
what?’ Popper had made his point. When we observe we look for certain
things. In research we set out looking for certain behaviours or
characteristics. We have a predetermined idea of what we’re looking for
and as we all know if we set out with expectations we’re quite likely to
meet them. Essentially this is the argument of the social
constructivists. Our existing knowledge determines our expectations and
our viewpoint. This is particularly noticeable in psychology with
researchers belonging to one approach or another, e.g. cognitive or
behaviourist.
3. Testing
theoretical predictions
Having
created models or theories we are able to make predictions based upon
these. We can then test these predictions with research. Work on
spatial memory in meadow moles produced the spatial adaptation model of
animal memory. Subsequent research on lizards showed this to be wrong
resulting in the pliancy model.
4.
Falsifiability
A concept
introduced by Popper in 1969. Having a theory that can be objectively
tested and ultimately proven wrong is what distinguishes science from
religion and pseudoscience such as psychoanalysis. Psychological
research tests an alternative or experimental hypothesis, however, we
are not seeking to prove this, rather we seek to disprove our null
hypothesis. As Popper put it;
‘No amount
of observations of white swans can allow the inference that all swans
are white, but the observation of a single black swan is sufficient to
refute that conclusion.’
In
psychology many theories have been tested over the years and been shown
to be wrong. Weiss’ replication of Brady’s ‘executive monkeys’
experiment highlighted a crucial error in the research.
Similarly
Schacter and Singer’s controversial research of 1962 was tested and
questioned on methodological grounds seventeen years later!
However,
there are concepts in psychology that do elude testing and
falsifiability. Freud’s hypothetical constructs, the Id, Ego and
Superego, along with Eros and Thanatos and the psychosexual stages and
the Oedipus complex can never be tested objectively. They will forever
remain non-falsifiable. Similarly Maslow’s hierarchy of needs.
5.
Replicability
Already
mentioned on numerous occasions above; others must be able to test your
findings. Generally in psychology, laboratory experiments can be
repeated, provided sufficient detail is included in the published
article. Much of the behaviourist approach has been tested many times
and the schedules of reinforcement for example are seen as close to
psychological fact as it’s possible to get. Piaget’s work has been
tested to death too!
Replication
in social psychology however is more hit and miss. Generally, research
such as that of Asch and Milgram that was set in tightly controlled
environments has been repeated. Research reliant on real life
observations is not always so easy to recreate.
In order to
replicate research all details need to be included in the write up,
including details about participants, procedures, design decisions and
of course the raw results. Sir Cyril Burt’s research (below) is a
lesson on what can happen when research is not published in full.
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On a
note of historical interest it is worth pointing out that Burt’s
work formed the basis of the eleven plus system in this country,
which I missed by one year. Testing at age 11 determined
whether you went to grammar school and got a good standard of
education or were relegated to a secondary modern school and got
a poorer standard. According to the argument, since
intelligence was largely genetic then being thick at 11 meant
that you’d always be thick so there was no point in wasting a
good education on bad genes!
Working with 21 pairs of MZ twins reared apart in 1955 Burt
obtained a correlation in IQ of 0.771. Eleven years later, and
now working with 53 pairs of MZ twins Burt’s figure for
correlation was remarkably still 0.771. |
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Leon
Kamin was the first to question the findings and subsequently
the co authors who Burt claimed to work with could not be
found. His work could not be verified since his wife burnt it
on his death!
This
led close friend of Burt, Leslie Hearnshaw, who had read the
eulogy at Burt’s funeral and had been chosen by Burt’s sister to
write his biography, to conclude that much of Burt’s research
had in fact been fraudulent.
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6. Paradigm
According to
Kuhn, a paradigm is the most important aspect of a true science.
Essentially a paradigm is a framework or central concept around which
the science fits. For example the Laws or relativity for physics.
As a science
emerges and develops it progresses through three distinct stages:
Pre-science
No clear
paradigm has yet emerged. There may be a central thread holding the
subject together but it is a broad church, perhaps embracing many
different theoretical perspectives and as yet unclear as to which one to
follow.
Normal
science
A widely
accepted view has emerged that seems best able to explain current
observations in the field. For example Newton’s Laws of Motion (prior
to Relativity).
Revolutionary science
A sort of
transitional phase to a new paradigm. As evidence accumulates and new
observations emerge the old paradigm may look increasingly shaky.
Gradually thinking in the area starts to gravitate (speaking of Newton)
to a newer paradigm. However, this tends to be a slow process as many
of the proponents of the existing paradigm refuse to give way.
Eventually however, there is a paradigm-shift as the new paradigm
acquires concensus. An example would be the movement from the
geocentric to heliocentric view of our solar system.
Applying
paradigms to psychology
I think you
can see where this one’s leading. Re-read the three stages above.
Where does psychology appear to be? I think the clue is in the phrase
‘different theoretical perspectives’ which seems to sum psychology up
quite nicely.
According to
Kuhn (1962) psychology is in the pre-science stage.
-
There is
no one central approach, rather a collection of different
theoretical ideas centred around psychodynamic, behaviourist,
cognitive and humanistic thinking.
-
Because
psychology covers such a huge area it tends to tread on the toes of
those around it. It overlaps with biology, sociology, neuroscience,
philosophy and so on, which have little in common with each other.
Of all the
theoretical approaches it is behaviourism that comes closest to having a
paradigm since it is simply a study of behaviour with the idea that
everything is learned.
However, you
psychologists feeling put down by not being seen as scientists (by Kuhn
at any rate) take heart. Many of the physical sciences struggle to
produce a paradigm. Chemistry for example sub-divides itself into
organic, inorganic and physical each with different assumptions and
approaches.
Peer review
(refereeing)
This is seen
as essential in scientific research and again relies on thorough and
accurate reporting of scientific research.
The process
doesn’t usually start until a report has been submitted for publication
in a scientific journal. Prior to publication the editor will ask
external scrutineers to look through the journals that have been
submitted and essentially pick out the best.
Research is
only published if:
-
It makes
an important contribution to scientific knowledge
-
It has
sound methodology
-
It is
ethically sound
However,
there are important problems with the process that may lead to bias.
Imagine you’re carrying out the process. What will impress you most, an
original study or a replication? A significant finding or one where
firm conclusions cannot be drawn?
Non-significant findings and repeated studies produce the ‘file-drawer
problem.’ They never see the light of day and result in a skewing of
scientific publications.
Generally
however, the process is seen to ‘add merit’ to the scientific approach.
Note: the
leaked emails of ‘climategate’ talked about rigging the peer review
process!
Are
scientific methods appropriate for psychology?
Fields of
research such as psychology and sociology attempt scientific methods of
study, for example the laboratory experiment. However, the very focus
of this research makes truly objective investigation difficult, some
would say impossible.
Unlike the
physical or biological sciences the focus of research is human behaviour
with all the added complications this brings. As we’ve seen time and
time again in the past two years there is no perfect way to observe or
research people.
The
laboratory experiment allows for tight control of variables enabling
cause and effect relationships to be established but it is woefully
short of ecological validity and there are serious issues with demand
characteristics. People behave differently when they know they’re being
observed.
To overcome
demand characteristics and the issue of validity we can attempt
naturalistic observations or field and natural experiments but then we
lose that tight control so we can’t be sure what’s causing what.
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The
Hawthorne works, site of one of a famous study on productivity
carried out between 1927 and 1932. Any change in work
conditions, such as adjusting lighting levels, resulted in short
term increases in production of telephone relays.
Researchers eventually realised it was knowledge of their
observations that was causing the effects. |
With any
method we also have the issue of expectations and blinkered viewpoints
that Popper claims make truly objective analysis impossible.
Nomothetic
versus idiographic
Psychology
has a trend to look for general rules of behaviour or cognition which it
formulates into models or rules. This is referred to as the nomothetic
approach. Fewer attempts are made to consider individuals and their
differences, the idiographic approach. One exception to this is the
approach favoured by the humanists:
Humanists
and their non-scientific approach
Perhaps in
the past I’ve given the impression that I don’t appreciate the
humanistic approach but that’s not true. Fair enough I tend to refer to
them as the ‘Lib-Dems’ of psychology, but I like the Lib-Dems
J.
However, unlike the other approaches there’s no sex and violence, no
hard-core genetic determinism and certainly no ping-pong playing
pigeons. Perhaps that’s why the AQA course generally passes the
humanists by, just a nodding glance of acknowledgement to Marie Jahoda
and her deviation from ideal mental health. There’s not a lot to hang
your coat on!
Unlike the
medical, behaviourist and cognitive approaches, humanists reject the
scientific approach to studying people. Its main proponents such as
Carl Rogers, Abraham Maslow, Rollo May and RD Laing prefer the
phenomenological approach, relying on detailed self-report of conscious
thoughts and analysis by qualitative techniques.
The
humanists therefore claim to produce a more holistic explanation of the
human condition that focuses on uniquely human characteristics such as
self-actualisation, hope, love, creativity and striving to be an
individual.
Social
constructionism
Prepare for
some philosophy! Social constructionism is the idea that reality
doesn’t exist as an external entity. Reality is essentially what we as
individuals interpret through our senses and our minds. Crucial to this
process is interaction and communication with others. The nearest we’ve
come to this concept during the course is Vygotsky’s concept of
internalization. According to the Lev-meister, we talk with more
knowledgeable others, watch how they solve problems and then their ideas
and their tactics become part of our way of thinking. As a result, our
understanding of the World is culturally determined.
Social
constructivists therefore appreciate that our current way of thinking is
relative. It is relative to the time in which we live and the culture
in which we live. Unlike more empirical approaches, constructionists
realise that what we know today will change tomorrow. The main
proponent is Gergen (Kenneth to his friends).
To try and
ground this in more concrete terms; consider the cognitive approach. It
makes use of present day technology to produce analogies for
cognitions. Currently it adopts the information processing approach in
which cognitive functions are all about inputs, processing and outputs.
Memory is described in terms of storage, deleting files and increasing
efficiency. Before the advent of mainframes and PCs cognitions were
likened to telephone exchanges. Tomorrow who knows?
Examples of
social constructs include language, games, money, A-level grades. More
controversially some see race, ethnicity and even gender as social
constructs. Apparently in the 1960s only three distinct races were
considered, today it’s over 30, suggesting that these things aren’t
quite as black and white as we like to think!
Research Methods in Psychology
Introduction
What follows
is meant as a summary or brief overview only of this topic area. It is
essential that a combination of class exercises and/or texts are used
with the notes to provide a fuller understanding of the issues covered.
Easily the best way of learning research methods is a combination of
reading followed by practise. Read a section, e.g. on levels of data
and then practise what you’ve just learned by answering questions on the
topic. Questions on the paper will require short response answers.
An overview
The board
requires that you have knowledge of the following areas and some texts
cover them in this order.
Ethical
issues
Deception
Consent
Right to
withdraw
Protection
from physical and psychological harm
Dealing with
ethical issues e.g. debrief, committees and guidelines
Research
Methods
|
Experimental
Laboratory
Field
Natural
Quasi
|
Non
experimental
Correlations
Questionnaires
Interviews and surveys
Case
studies
Content analysis |
Research
Design and implementation
Aims and
Hypotheses
Research
design
Independent,
dependent and extraneous variables
Sampling
Pilot
studies
Reliability
and validity
Demand
characteristics and investigator effects
Data
analysis
Analysis of quantitative data
Measures of central tendency and of dispersion
Correlation coefficients
Presentation and interpretation of quantitative data
Analysis and interpretation of qualitative data
Presentation
of qualitative data
However,
this is not a logical teaching order so although this booklet will cover
all the stuff mentioned above it will follow a different sequence and
hopefully one more similar to the route taken in class.
Government
Health warning
The
following information does contain sums and other material likely to
cause offence to the squeamish. However, I’ll endeavour to keep the
aforementioned to an absolute minimum and will, wherever possible avoid
the gratuitous use of numbers!
Ethical
issues in Psychological research
Ethics are
the moral codes laid down by professional bodies to ensure that their
members or representatives adhere to certain standards of behaviour.
All scientific bodies have such codes but those in psychology are
particularly important because of the subject matter of the topic.
1.
Psychology is unlike most other subject areas in that its subject matter
is entirely human or animal. Because of this practically all research
involves living things that can be caused physical or psychological
harm.
2.
Psychological research also needs to consider the wider community.
Milgram’s research taught us something unpleasant about the human race
in general. Some research, for example studies on IQ, have been used to
discriminate against different races or ethnic groups. It could be
argued that Bowlby’s research was used to discriminate against women,
making them feel guilty for not being at home caring for their
children.
3.
The
knowledge gained from psychological research can be exploited by people
or groups to gain an advantage over others. Skinner’s work on behaviour
shaping could be abused in this way.
Protecting the individual in psychological research
Many of the
ideas mentioned in this section will be raised as we cover other topics
later in the year and particularly in the last topic on social
influence.
-
Deception
-
Consent
(informed or not)
-
Protection of participants from physical and psychological harm
-
The
right to withdraw
-
The
right to withdraw data
-
Confidentiality and Privacy
We shall
then consider ways of determining whether or not studies should take
place, and strategies for minimising risks if they do.
 |
Mr Wallace
with the ‘dicky ticker.’
Milgram’s procedure involved deception, lack of informed
consent, physical and psychological harm, denied participants
their confidentiality and right to withdraw (allegedly).
However, a therapeutic debrief was provided and no ethical
guidelines were broken since they didn’t exist at the time!
Did
what we learn justify these methods?
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Deception
Examples of
studies involving deception: Asch, Milgram, Cruchfield
Deception
involves either concealing the real intention of a study from
participants or taking steps to mislead them at the outset. All of the
examples above used the second ploy, deliberately lying to participants
about the genuine reason for a study. Two of them also used stooges or
confederates (people pretending to be participants who are really part
of the experimental set up). The use of stooges always means deception
has been used.
However, is
deception necessary? The researchers above would all argue that their
experiments could not have taken place without it. Imagine if Milgram
had said at the start, ‘Mr Wallace is really a stooge, who will scream a
bit but will receive no shocks.’ The study would have told us nothing
of interest and obedience would doubtless have been close to 100%.
To a lesser
extent nearly all studies involve an element of deception in that it
generally isn’t a good idea to tell your participants what you are
looking for in advance. Menges (1973) estimated that as few as 3% of
studies involve no deception at all. When using the BEM sex role
inventory to test gender, telling male participants in advance that you
are trying to find how masculine or feminine they are will almost
certainly influence the way they respond to the questionnaire!
Baumrind on
the other hand argues that deception is always wrong since it prevents
informed consent (see below), researchers have an obligation to protect
their participants (see below) and psychologists should be seen as
professional and therefore trustworthy.
Debriefing
It is really
a matter of common courtesy to debrief your participants at the end of
any procedure and inform them of the point of the research.
Debriefing is crucial if any form of deception has been employed.
A proper
debrief should:
1. Inform
participants of the purpose of the research
2. Ensure
that there are no negative or unforeseen consequences of the procedure
3. Ensure
that the participant leaves in ‘a frame of mind that is at least as
sound as when they entered.’ (Aronson 1988).
4. Give the
participant the right to withdraw their data and to see the finished
write-up of the report if they so wish.
As well as
having the best interests of the participant in mind, debriefs can also
be a useful source of additional information in an experiment.
Participants may tell you things that you would otherwise not be aware
of.
 |
George ‘dubya’ being debriefed following his eight year
participation in a study into the effects of having a Dick* in
the Whitehouse.
George is thanked for taking part, assured that his behaviour
was normal and given the right to withdraw (from Iraq).
Researchers are assured that his frame of ‘mind’ has not
been impaired by the lobotomy. |
Therapeutic debriefing
In extreme
cases such as Zimbardo’s study, participants may receive questionnaires,
be asked to complete diaries and have follow up meetings with the
experimental team. In the case of Milgram some participants also
received follow up psychiatric visits!
Consent and
Informed consent
Consent
Simply
refers to participants willingly and voluntarily taking part in your
experiment. Milgram and Asch for example did obtain consent. In the
case of Milgram he placed his infamous advert in the local paper and
people turned up. During WWII the Nazis carried out many procedures on
prisoners without their consent. Following the war it was decided that
consent should be enshrined as a basic human right.
Informed
consent
This refers
to participants giving their consent in full knowledge of the aims of
the study, the expectations of them and their right to withdraw and to
confidentiality. This clearly was not the case with Asch or Milgram,
but arguably was with the Zimbardo procedure. This raises the issue of
whether fully informed consent is ever possible. If researchers know
the likely outcomes of a study then what is the point in carrying it out
in the first place?
Informed
consent and deception are closely related in that there cannot be
informed consent in any situation where deception is used.
Special
cases
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Children
Children under the age of 16 are deemed not to be old enough to
give consent. In this case permission has to be sought from
parents or guardians. |
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Detained
People in prisons or psychiatric hospitals need particular
consideration. Prisoners may feel pressured into taking part as
failing to do so may prejudice their situation. Similar
concerns apply to patients. Additionally with psychiatric
patients permission may need to be sought from either relatives
or psychologists. |
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Students
It
has been common practice by many universities to expect students
to participate in experiments as a requirement of the course.
In my fresher year I was expected to earn a certain number of
points by being a participant in studies. Those involving pain
(like the electric shocks I suffered in acquiring my aversion to
the number 3) gained higher points. Here a certain degree of
coercion is used and may not be entirely ethical. |
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Field experiments
Piliavin conducted research on the NY underground in which
stooges pretending to be blind or drunk (not both!), fell over.
The research team observed the reactions of bystanders. In
situations like this ‘participants’ are not aware that they are
taking part in a study so cannot give consent. In addition it
is usually impossible to carry out debriefs afterwards |
Various ways
of overcoming the issue of consent will be discussed later. These
include presumptive consent and prior general consent.
Protection
from physical and psychological harm
Physical
harm
The BPS
guidelines suggest that participants should be exposed to no more risk
than they would be in everyday life. For example people driving cars
are exposed to a certain level of risk. If psychologists wish to study
some aspect of driving related behaviour then the procedure they use
should not put their participants at greater risk than this.
There are
occasions when researchers have caused their participants physical harm
although these tend to be rare. Milgram appears to have delighted in
the response of some of his participants who would ‘bite their lips and
dig their fingernails into their flesh. Full blown, uncontrollable
seizures were experienced by three subjects.’ (Wrightman and Deux
1979).
Psychological harm
This is more
difficult to gauge but may involve embarrassment, loss of self esteem,
stress and anxiety.
Asch,
Zimbardo and Milgram procedures would all have involved loss of self
esteem, embarrassment and some stress, and in the case of Milgram and
Zimbardo, extreme anxiety.
Confidentiality is one way of protecting participants from psychological
harm. If you do something shameful or embarrassing then others not
knowing will help reduce the impact.
Confidentiality
The data
protection act requires that the identity of all participants remains
confidential. As well as safeguarding privacy there is an obvious
practical benefit from this approach. Participants are unlikely to
volunteer for procedures if they believe that their identity and
behaviour will be divulged.
There were
clear breaches of confidentiality in the Milgram and Zimbardo studies as
in both cases participants were secretly filmed.
Guidelines
require that participants are not identified unless they give their
permission and various methods may be used to disguise their identity.
For example in case studies patients may be identified only by their
initials such as KF or HM.
The right to
withdraw and to withdraw data
This should
be available and made clear to participants before the research starts.
Both Milgram and Zimbardo claim that withdrawal was possible in their
studies although when questioned afterwards it is clear that not all
participants realised this.
Advance
payment
was an issue
in the Milgram study. This may put additional pressure on participants
who may feel obliged to earn the money that they have received.
The debrief
should make it clear that participants have the right to withdraw their
data on being told the nature of the study. If serious deception has
taken place then participants have the right to witness their data being
destroyed!
Dealing with
the ethical issues
This is a
favourite question in which you are expected to describe and/or evaluate
measures taken by psychologists to minimise the adverse effects of
research. Obvious points to mention would be seeking consent, avoiding
deception, providing the right to withdraw, debriefs and
confidentiality.
For fuller
marks some or all of the following could also be discussed:
-
Ethical
guidelines and codes of conduct
-
Cost-benefit analyses
-
Ways of
obtaining consent and avoiding deception
Ethical
guidelines and codes of conduct
Following
the immoral experiments of the Nazis in WWII, each country set up its
own set of guidelines for performing scientific research. In Britain
the British Psychological Society (BPS) and in the USA the American
Psychological Association (APA), produce codes of conduct for both
experimentation and for clinical practice.
For human
participants the codes cover topics already mentioned such as deception,
consent, withdrawal of data, confidentiality etc.
Additionally
all institutes that perform psychological research have ethical
committees that consider whether or not particular pieces of research
should be carried out. This body should have non psychologists that can
express more objective views on research.
Cost-benefit analyses
Committees
may carry out cost-benefit analyses in which the likely benefits of a
particular piece of research is weighed up against the costs to human or
animal participants. Put simply does the knowledge we gain about human
behaviour and the advantages this might have for the wider population
warrant the suffering or embarrassment of a few individuals? Such
analyses are notoriously difficult to carry out objectively,
particularly in advance of a piece of research. Psychologists still
argue about the costs and the benefits of the Milgram procedure, and
that’s with the benefit of forty years of hindsight! Additionally the
costs to the larger social group may also be considered, for example and
an ethnic or racial group or women etc.
Obtaining consent and avoiding deception
Presumptive
consent
(of ‘reasonable people’)
This asks
people for their views on a particular procedure. If generally they
find it acceptable then that procedure is used… but NOT on those asked.
Prior
general consent
A pool of
possible participants would be asked for their views on research. For
example they may be asked about their views on the use of deception or
embarrassment during research. Only those participants who consider
these ploys acceptable would then be selected for later research
involving fibs etc.
Role
playing
People are
asked to act out the role of participants in problematical studies
involving deception or psychological harm etc. Clearly these are less
than satisfactory since people can only guess at how they would respond
in such situations. When asked, fewer than 1% of people believe that
they would obey in Milgram’s study!
Research Methods
The Experiment
-
Definition of an experiment
-
Advantages and disadvantages of the experimental method
-
Types of
experiment
Definition
In an experiment a variable is manipulated to see what effect it
will have on another.
For example
if we wanted to know whether caffeine affected reaction times:
We could
take two groups, give one group coffee (experimental group) and compare
them to another group without coffee (control group).
We would then set them a task designed to measure their reaction
times.
In
experiments there are 2 variables:
-
Independent variable
(the one we alter or manipulate) in this case whether or not the
person has had coffee.
-
Dependent variable
(the one that alters as a result of what we do), in this case
reaction time. The dependent
variable is usually the one we measure or record.
Not rocket
science, BUT the problem is always remembering which is which.
The way I do it is simply to think of the dependent
variable as the one that depends on what we do!
In this case
reaction time (dependent variable) depends on whether or not the
participant has had a cup of coffee.
Crucially an
experiment allows us to establish a causal link between the IV and the
DV. Following an experimental procedure we should be certain that the
alteration we have made in the IV has caused the change in the DV.
Other
variables
The I.V. and
D.V., as we psychologists refer to them, are not the only variables to
worry about.
In the
coffee experiment suppose we find that the coffee group have faster
reaction times, can we be certain the coffee has caused this.
Other possible reasons:
-
The
experimental group (on coffee) might just by chance contain people
with faster reactions
-
Perhaps
we measured one group in the morning, the other in the afternoon.
-
Perhaps
those in the control group had a hangover etc.
Confounding
variables
These are
variables that get in the way of our results or make our results
difficult to interpret.
Think of
Brady’s executive monkeys. Brady assumed that being in control had
caused the stress that lead to the ulcers. Control being the IV and
ulcers being the DV. In fact it was more likely to be the activity
levels of the monkeys that caused the results. This is an example of a
confounding variable.
Common
confounding variables include:
-
Intelligence of participants
-
Personality of participants
-
Gender
of participants
-
Time of
day
-
Weather
-
Noise
levels
-
Temperature…
Obviously in
an experiment we take steps to minimise these, for example we could
ensure that the procedure is carried out at the same time of day, in the
same room, with similar temperature settings etc.
Laboratory experiments
Lab
experiments don’t have to be carried out in a laboratory. However, any
experiment that is carried out in a special, tightly controlled
environment is classed as laboratory. Importantly it is obvious to
those taking part that that they are in an experimental procedure.
Laboratory
experiments are therefore artificial and tightly controlled, leading to
the following advantages and disadvantages:
|
Advantages of lab experiments |
Disadvantages of lab experiments |
|
Cause and effect:
We can usually see that the IV has caused the alteration in the
DV. Provided we have controlled our experiment we should be
able to show that it was the coffee that was responsible for the
faster reaction times. |
Lacks ecological validity:
As
we’ve seen so many times (e.g. in memory and in Milgram),
experiments, especially those in laboratories are very
artificial. Can they really tell us how people will behave in
real life situations?
|
|
Replication:
Provided care has been taken in conducting and reporting the
procedure another person should be able to repeat your procedure
to see if they get the same results. |
Demand characteristics:
New
one for you; this refers to participants behaving differently
because they know they’re being watched. We saw this in Milgram.
It could be that they guess what you want and try to please the
experimenter, e.g. by obeying!
|
Laboratory
experiments we have seen this term:
Most studies
on memory would have been lab experiments: Brown-Peterson technique,
Baddeley’s study of encoding, Loftus’ research into leading questions,
Sperling’s study of sensory memory etc…
Not all
experiments however are carried out in artificial settings and not all
allow full control of the IV. Other types of experiment are covered
next:
Field
experiments
Not, as the
name implies, experiments conducted in fields, although they could be!
More likely
settings would include the work place, school, the street etc.
Basically the same rules apply: an independent variable is manipulated
to see how it affects a dependent variable. Confounding variables can
still get in the way, and cause and effect can still be determined.
However, the setting is more natural.
|
Advantages of field experiments |
Disadvantages of field experiments |
|
Ecological validity:
because the settings are more natural it is assumed that people
will behave more naturally, so field experiments should have
greater ecological validity. |
Less
control of variables:
the
experimenter has less control over the environment so more
variables may affect the outcome. As a result we cannot be
certain that the IV has caused the change in DV. Cause and
effect relationships are therefore difficult to establish.
|
|
Demand characteristics:
these can be less since participants may not be aware that they
are in an experiment, as was the case with Hofling! |
Ethics:
If
patients are unaware of the study how can the consent to take
part or withdraw from the experiment? |
|
|
Replication:
It is difficult to repeat the procedure exactly as it was the
first time. |
In practice
it can be difficult to distinguish a laboratory experiment from a field
experiment. Consider the Brewer and Treyen’s office schema study. This
is clearly an experiment and in an artificial setting, but the
participants were not aware at the time of the procedure, that they were
taking part in a study so there behaviour was quite natural. Similarly
with Loftus’ study on weapons focus. Participants listened to an
argument whilst waiting to start an experiment. Again the setting was
artificial and there was full control over the IV (blood soaked knife or
pen). However, again the participants were unaware of the procedure so
again their response would have been natural. Are these laboratory
experiments or field experiments? No right answers really. However,
the crucial thing is that you can justify your answer and explain the
positive and negative points.
Natural
experiments
Not, as the
name implies, experiments carried out in the buff, although they could
be if you were comparing the memory of those who naturally prefer to go
au naturelle with those who prefer to wear clothes. These are
similar to and often confused with quasi-experiments, but there is one
crucial difference. Natural experiments take advantage of a
naturally occurring event. The effect of the eruption of Mount St
Helens on stress related illnesses is the one all the texts prefer to
mention. In this case the IV was the eruption, a naturally occurring
event.
A better
example and one that we’ve studied is Hodges & Tizard’s study of
institutional care which examined the effect of different types and
duration of care on the children’s subsequent behaviour and development.
IV is the
type and duration of care (in this case not controlled by the
researchers, it happened anyway). DV is the effect this has on
subsequent development (and which can be measured using various tests).
|
Advantages of natural experiments |
Disadvantages of natural experiments |
|
Demand characteristics:
it
is often the case that the experimenter isn’t even present when
the event occurs, thankfully in the case of Mt Saint Helens! As
a result participants are not trying to please the researchers. |
Lack
of control:
the
researchers have no control at all over the variables and there
may be lots of confounding variables. In the Mt St Helens case
ill health caused by smoke, or stress due to loss of house etc. |
|
Research opportunities:
it
is possible to research events that it would be unethical to
study any other way or that may be impossible to set up. |
Replication:
in
some cases clearly impossible, in others very difficult. As a
result it may be impossible to check the validity of research. |
|
|
Cause and effect:
following on from lack of control, it may be impossible to
decide if the IV is causing the change in the DV. |
Quasi-experiments
Not, as the
name implies, experiments were you run around in the dark pretending to
shoot each other with lasers! But they could be if you were looking for
age or sex differences.
In a real
experiment you can manipulate the IV and you can decide who goes in
which group. In your study on coffee you decide which participants go
in which group. However supposing you wanted to see if 40-somethings
had faster reactions than teenagers: you never know it could happen!
In one group
your participants will have to be teenagers and the other group
will have to comprise 40-somethings. You are unable to randomly
allocate your participants to the different groups. Similarly with sex
differences; by definition the boys are going to be in one group and the
girls in the other!

Experimental
research design
Here we
decide how we are going to sort or group our participants. Do we use
the same people in all conditions or groups, or do we choose different
people for different conditions or groups? In some cases, as we’ll see
the decision is made for us. In others the solution isn’t so obvious
and there may be pros and cons for each.
Repeated
Measures Design
Here we use
the same participants in each group or condition.
For example,
returning to the earlier experiment on coffee and reaction times.
In a
repeated measures design we could give our group of participants the
test on day one with no coffee and record their reaction times.
The next day
we could repeat the procedure, with the same group of people, but
this time give them coffee before the experiment began.
Advantages
The two
groups have the same age, sex, personality, ideas, past experiences, IQ,
reaction times (crucially for this one) etc. They are perfectly
matched. They are the same people!
Disadvantage
Order
effects:
Assuming, as
we expect the group do better on the second day, can we be sure that
this increase in performance is due to the coffee? It could be that
they’ve had the chance to practice the task the day before! It’s not
surprising they’re better the second time around. This is called order
or practice effect.
Boredom:
Of course, on some tasks it could work the other way, and a task done
the second time shows a deterioration because they’re fed up with doing
it.
Extra
materials:
For example if you use the same participants for two memory experiments
you will need two lists of words etc. for them to recall. This
introduces other variables. Perhaps the second list is easier than the
first.
|
Counterbalancing
To
overcome order or boredom effects we could use ABBA.
One
half of the participants could do no coffee followed by coffee
the next day (condition A followed by condition B).
The
other half could do coffee on the first day and no coffee on the
next day (condition B followed by condition A).
Hence ABBA
(nothing to do with thanking anyone for the music!).
In
some cases repeated measures has to be used:
If
you’re comparing gender with subject choice at AS you use the
same people in each condition and compare a persons gender score
with their AS choices.
Examples we’ve seen this year
The
love quiz: the same
people take each questionnaire
The
44 thieves: later
behaviour is compared to early attachments in same people
|
 |
Independent
Measures design
You guessed
it. If we used the same people in each group last time, this time we
use different people in each group. Clearly this overcomes practice and
boredom effects ‘cos they only do it the once!
Each
participant is randomly allocated to one group or the other, so in our
coffee experiment:
One group,
comprising one set of participants do the test with coffee
The other
group, comprising a different set of participants do the test without
coffee.
Sorted, no
problems with practice or repeat effects or with boredom or tiredness
effects.
However
Can we be
certain that the likely faster reactions of the first group are down to
the coffee?
It could be
that the participants that we’ve randomly assigned to that condition
have naturally faster reactions. They may be younger, or some of them
may engage in activities that require fast reactions.
In other
experiments, sex, personality, age, IQ etc. could all be an issue
because the participants are going to differ on all of these.
There are
some occasions when independent measures design has to be used:
Sex
differences
Age
differences
By
definition the two conditions are different. You couldn’t have someone
in the male condition and the female condition, or in the under
30 condition and the over 30 condition!
Advantages
1.
No
order or practice effects
2.
Can
use the same stimulus material (such as word lists in memory) for each
group
Disadvantages
1.
Participants are not matched in terms of IQ, personality, age etc.
2.
You
will need twice as many participants.
Clearly
these are the same as the advantages and disadvantages of repeated
measures but in reverse.
Matched Pairs Design
This is the
ideal compromise. In the reactions experiment you would have different
people in each condition, i.e. some would have the coffee and others
not. However, the two sets would be matched in terms of IQ or whatever
characteristics are relevant, in this case reaction times, age etc.
Advantages
1.
No
order effects since each participant only does the task once
2.
You
can use the same material twice
3.
Groups are similar in terms of individual characteristics
Disadvantages
1.
Very
time consuming and difficult to match all of your participants in this
way
2.
It is
impossible to match people for all characteristics even if you were to
use MZ twins between the two groups!
Observations
 |
These are a vital tool in the psychologists armoury and if done
properly can provide oodles of ecologically valid and detailed
information about all manner of behaviours.
However, they also have many pitfalls and raise a whole
host of methodological and ethical issues.
Observations can be subdivided in many ways each with
their own distinct advantages and disadvantages.
In unit one we have seen a few worthy examples of
observations including the strange situation, Lorenz’ work on
geese and in addition to these you should also be familiar with
Bandura’s bobo doll research.
The following divisions of observations will be considered:
Naturalistic v controlled
Structured v unstructured
Participant v non-participant
Disclosed v undisclosed |
Naturalistic Observation
This
is an easy one to explain. People or animals are observed in their
natural environment, without any sort of intervention or manipulation of
variables and without their knowledge.
Examples
include:
-
Seyfarth
& Cheney’s research on the warning calls of the vervet monkey
-
Sylva’s
study of play in young children.
-
Much of
the work carried out by Konrad Lorenz
Ethologists
specialise in studying animals in their natural environment.
 |
|
Was
it the tickly beard of the alluring aroma of his rough shag?
Either way Lorenz was still attracting the birds into his 70s. |
The
researcher observes behaviour in its natural environment as many of the
ethologists studying animal behaviour record their information.
Ainsworth’s study of attachments in Ugandan women would be a human
example of naturalistic observation.
|
Advantages of naturalistic observation |
Disadvantages of naturalistic observation |
|
Ecological validity:
Clearly this provides data that is very high in ecological
validity since it has not been tainted by observer intervention
with the observed not usually knowing that their behaviour is
being watched. |
Reliability:
there is the issue of bias. For example if a researcher is
looking at aggressive acts in a football game and assumes that
boys are going to be more aggressive, the results may
inadvertently be interpreted in this way.
|
|
Demand characteristics:
For the same reason there should be no demand characteristics.
If you’re not aware that you’re being observed then you won’t be
trying to please the researcher. |
Ethics:
are a major problem with many observational studies and
especially with naturalistic. Not knowing you’re being watched
creates issues with privacy and participants not consenting to
take part |
|
Detailed:
Information collected tends to be more detailed and provides a
fuller idea of behaviour than the sort of information that can
be collected in a laboratory. Think of the criticisms of
behaviour in the strange situation |
Cause and effect:
However control of the environment is not possible and
confounding variables make it impossible to determine cause and
effect relationships. You cannot be certain what factors are
creating the behaviour being observed |
|
Sometimes this is the only possible way of doing research,
especially if people are unwilling or unable to complete
questionnaires or interviews.
|
Replication:
in
many cases it would be impossible to recreate exactly the same
situation so that someone else could verify your findings.
|
Controlled
As the name
suggests the researcher in some way manipulates the behaviour of the
observers or the observed. Ainsworth’s strange situation is the best
example seen to date with researchers organising the behaviour of the
mother and stranger to see how the child reacts. Other examples include
the Bobo dolls and Piliavin’s work on bystander apathy on the New York
subway.
These allow
for greater control of confounding variables meaning it is easier to
establish cause and effect relationships.
However,
they are lower in ecological validity since the trigger for the
behaviour is usually not a natural event. Often, but not always,
participants may also know they are being observed creating demand
characteristics.
Disclosed
Participants
know they are being observed. This reduces ethical issues of consent
and privacy but reduces validity due to increased demand
characteristics.
Undisclosed
Participants
are unaware of the observation. This raises ethical issues (privacy and
consent) but increases validity by reducing demand characteristics.
Sometimes one way mirrors might be used to discretely observe people,
for example shopping behaviour in a supermarket.
Participant
Here the
researchers get involved with the group of participants they are
observing. Festinger (1956) joined a cult to observe how they would
react when their predicted end of the World deadline came and went. The
cult leader was able to reassure his flock that their prayers had saved
the planet! This is an example of undisclosed participant observation.
On occasions researchers may join in but make others aware of their role
as psychologists.
On occasions
researchers have been able to infiltrate groups and remain members for a
period of time allowing for detailed, longitudinal information to be
gathered, for example about the behaviour and motivations of street
gangs and religious cults. It is difficult to see how such groups could
be studied in any other way.
Clearly
there are ethical issues with this type of deceitful observation and the
researcher themselves may unwittingly interfere with the group dynamics
and the behaviour of the group.
Non-participant
The more
likely scenario in which participants are observed from a distance
rather than the researchers infiltrating the group.
Ethics
of observations
Observations
raise a number of unique ethical issues. These vary depending on the
nature of the observation taking place but here are a few:
Consent:
participants are often unaware of being observed so have no opportunity
to consent to taking part in your research.
Debrief:
often there is no opportunity for a debrief. For example in Piliavin’s
observation of bystander apathy on the New York subway, participants
were observed without their knowledge and would have left the train
before researchers had chance to debrief.
Deception:
participants being unaware of observation is deception in itself.
Additionally, researchers may cause additional deception by using
stooges. Again Piliavin used members of the research team to pretend to
be blind or drunk.
|
 |
 |
 |
|
Controlled observation: Bandura altered the conditions while
children watched the doll being hit. |
Participant observation: Marsh (1996) joined football fans to
observe their behaviour. |
Naturalistic observation: Seyfarth and Cheney recorded the calls
of vervet monkeys. |
Correlational analysis
In the past
year we’ve seen lots of examples of this. For example whenever I’ve
criticised a study because it doesn’t show cause and effect it’s
probably been a correlational study.
An example:
For example
we could look for a correlation between IQ and performance at GCSE or
A-level. Common sense would perhaps tell us that students that have
higher IQs are more likely to perform well at GCSE.
In year 13
we look at the controversial area of IQ and find that there is a high
correlation between the IQs of MZ twins. If one twin has a high IQ it
is likely the other does too. This is taken as evidence for the nature
or genetic determination of IQ. However, as we will see there are a
host of other reasons why this might be the case.
Types of
correlation
Positive:
the most common; as one variable increases so does the other, e.g. IQ
and GCSE score in the example above.
Positive
Negative

Negative:
as one variable increases the other decreases, e.g. it might be fair to
assume that the higher your stress levels the lower your life
expectancy. Again we are unable to show cause and effect. As mentioned
frequently in ‘Stress,’ illnesses could be due to secondary habits such
as smoking, poor diet etc.
|
Advantages of correlations |
Disadvantages of correlations |
|
Correlations allow us to study links between variables that
could not be studied in any other way. We could not inflict so
much stress on a person that we endanger their life. However,
we can use a correlational analysis to show a possible link
between the two occurring naturally.
|
Cause and effect: do I really need to explain this one?
A
correlation shows a possible link between 2 variables it does
not prove that one causes the other, e.g. smoking and heart
disease. |
|
Economical and fast: large amounts of data can be compared
quickly and cheaply, e.g. by using a questionnaire to collect
data. |
Correlations can disadvantage certain people in society if
misused. For example it was established long ago that blacks
under perform on IQ tests compared to whites. This knowledge
was misinterpreted as evidence of white superiority.
|
Case studies
These
involve study of an individual, small group, institution or an event. A
case study can involve a whole host of techniques including
observations, questionnaires, surveys, interviews, testing and even on
occasion experiments. They are frequently longitudinal in nature and
may also involve asking others, such as friends and associates.
Examples:
Clive
Wearing, HM, KF, S, Genie, Czech twins, Anna O, Little Albert, Little
Hans, Phineas Gage
|
Good
points
They
provide a wide variety of in-depth and detailed information that
would be impossible to acquire using heavily controlled
situations such as experiments. They can offer provide a real
feel for what it is like to be suffering from a particular
disorder or be involved in a certain situation
They
often provide the only method possible of studying a certain
condition or event. It would not be possible to artificially
re-create situations such as Genie or HM experimentally, so our
only access to information about privation or severe amnesia is
through case studies.
|

|
|
|
However
They it is
notoriously difficult to generalise from a case study and create a
general theory. Case studies by their very nature are one-offs or
unusual and often involve people who are not themselves representative
of the general population. The case of Genie and the Czech twins shows
this nicely. Both suffered severe deprivation over a prolonged period
but their outcomes are very different; the Czech twins seeming to make a
full recovery, whereas, as far as we know, Genie never recovered from
her early problems.
Often case
studies require an element of retrospective data collection, with
parents, friends etc being asked to think back to the participants
earlier years. Retrospective data collection is not reliable.
Objectivity
by the researchers can be difficult, with psychologists getting too
close to patients as with the case of David Rigler and Jean Butler and
their research/fostering of Genie.
Confidentiality can be an issue though some of this can be overcome by
the use of pseudonyms or initials.
Interviews
There are a
number of species of interview each with their own advantages and
disadvantages. I’ll consider the main ones only:
Informal
interviews
The
interviewer has an aim in mind at the outset but is willing to be
flexible about getting answers. The interviewer tries not to direct the
interviewee but instead listens and lets the interview take its natural
course.
|
Advantages |
Disadvantages |
|
Lots
of information can be gathered |
Difficult to analyse, especially if different participants
discuss different issues |
|
Interviewee made to feel relaxed |
Low
reliability |
Clinical
interview
These were
made popular by Freud and in particular Piaget and are a type of
informal interview. Piaget for example would read ‘moral stories’ to a
child and start off by asking the same questions to all the children,
for example ‘who is the naughtier boy in the stories.’ However, follow
up questions would be informal and vary from child to child.
Structured
or formal interviews
These follow
a set pattern with the interviewer having prepared a set of questions in
advance that are asked in a particular order.
Note:
sometimes the questions may be open and allow the interviewee to respond
how they like, for example ‘how did you feel when Freddie ate your pet
hamster?’ Or they can be closed and allow only a ‘yes’ or ‘no’
response. For example ‘were you upset when Freddie ate your pet
hamster?’
|
Advantages |
Disadvantages |
|
Easily replicated |
Little flexibility so important points may be missed |
|
Data
is easier to analyse |
Questions may be ambiguous (think of the SRRS for determining
stress levels). |
|
Data
is less likely to be influenced by the interviewer |
This
format may encourage brief answers |
Limitation
of interviews in general:
Social
desirability bias
We all like
to create a favourable impression. When faced with an interviewer we
are less likely to be honest than when filling out an anonymous
questionnaire. For example people being questioned about their love
life are likely to exaggerate in face to face interviews.
Lie scales
can be introduced to assess how honest answers may be. For example if
people were being questioned about their childhood a ‘lie question’
might be; ‘As a child did you always do as you were told first time and
without moaning?’ A response of ‘yes’ would be assumed to be a fib and
indicate that perhaps the interviewees answers may not be reliable.
Questionnaires
We all know
what they are and have all filled lots of them in. Basically a
questionnaire is a list of written questions that is able to gather lots
of relevant information relatively quickly and cheaply.
The biggest
problem is wording of the questions. Again there is the issue of ‘open’
or ‘closed’, but more importantly, as we saw in EWT, the issue of
leading questions. These are a favourite of politicians or of
newspapers that want to find support or criticism of a particular
issue. For example imagine you wanted to find out if people wanted more
money spent on the NHS, a relatively neutral question might be
‘Should more
money be spent on the NHS?’
The Mirror
(presumably wanting a ‘yes’ response might get their pollsters to ask:
‘Should
extra money be provided to the NHS to take care of Britain’s sick and
elderly?’
Whereas the
Telegraph (being very stereotypical here) may get their pollsters to
ask:
‘Would you
be happy to pay more taxes to fund bureaucracy in the NHS?’
Rather
extreme examples admittedly, real surveys carried out by experienced
pollsters would be far more subtle, but you get the idea!
It is always
a good idea to test your questionnaire in a pilot study first to make
sure it doesn’t take hours to complete and that participants understand
the questions. Feedback like this may provide ideas for follow up
questions to be asked in the real study.
|
Advantages |
Disadvantages |
|
Lots
of people can be tested quickly |
Lots
of questionnaires will not be returned! |
|
This
allows more reliable generalisation to the overall population |
People may tell fibs. Even in anonymous questionnaires this may
be an issue. Again lie questions may be included, e.g. in
Eysenck’s Personality Questionnaire (EPQ). |
|
Data
can often be analysed easily |
|
Typical
questions on Research Methods
Describe two
disadvantages of investigations using correlational analysis (2 + 2
marks)
Identify the
research method used in this study and explain one advantage and one
disadvantage of this method.
(2 + 2 marks)
Give one
advantage of using a questionnaire in this study. (2 marks)
Following
the survey it was decided to carry out an observational study into
under-age drinking. Outline procedures for carrying out such an
observation. (6 marks)
Content
analysis
Content
analysis studies human behaviour indirectly usually by studying the
things we produce, e.g. television programmes, magazines etc.
An analysis
of what we produce should be able to tells us a lot about the way we
structure our society and about our values, prejudices and so on. For
example a content analysis of television advertisements of the 1970s
would probably paint a far more sexist view of the World than that
present today, certainly in the UK at least.
Manstead and
McCulloch (1981) watched 170 television advertisements in a week and
scored them on a whole range of factors such as gender of product user,
gender of person in authority, gender of person providing the technical
information about the product and so on.
|

|
The
classic ‘Do the Shake and Vac and put the freshness back’ advert
of the 1980s portrayed a woman obsessed by the fresh smelling
nature of her house.
|
Good points
They can
produce lots of detailed and easily analysed material about a particular
aspect of society.
Since the
research is observational it is high in validity.
Provided the
information is well presented and sufficient records are kept and
published relating to the material sourced and the content analysed
replication and verification of results should be possible.
However
There is the
possibility of bias, with the observations being subjective. To
overcome this a number of raters should be used (inter-rater
reliability)
The choice
of material and content to be analysed also introduces a potentially
huge source of bias.
Other
research methods
As already
stated, many research studies use a combination of techniques. We saw
this with case studies but as Cardwell and Flanagan point out, Schaffer
and Emerson’s Glasgow babies study used natural observation, interviews
and even occasionally experiments when mothers recorded how the children
responded to a series of everyday events.
Meta
analysis
The results
of a number of studies (usually buy a variety of researchers) in a
related area are combined to see if overall trends are visible. This can
increase reliability since contradictory findings may be uncovered.
However, different studies may be difficult to compare because of
different sampling, design and methods used.
Longitudinal
studies
A favourite
with developmental psychologists since they allow children to be
revisited to see how they change and grow over time.
The big
disadvantage is attrition. People move to different areas or become
impossible to contact.
Research
Design and Implementation
Aims and
Hypotheses
Aims
When
carrying out a piece of research it is essential that you have an aim in
mind. This needs to be reasonably precise, for example ‘I’m gonna study
memory’ would not be sufficiently precise. However the aims are
broader, or less precise than the hypotheses. A suitable aim for memory
might be ‘to see if age affects the duration of STM.’
Miller’s aim
was to discover the capacity of STM.
Milgram’s
aim was to see if normal people would obey when told to kill someone!

Hypotheses
These are
more precise and should be operationalised, i.e. give some clue as to
how the research will be carried out. You must remember that two
hypotheses are included:
a.
Experimental or alternative hypothesis
This makes
your prediction, for example:
‘As age
increases the duration of STM decreases.’
b. Null
hypothesis
This might
at first glance seem redundant, since what you are saying is that you
will not find what you’re expecting. A suitable null hypothesis for the
experiment above could be:
‘Age will
have no effect on the duration of STM.’
The two
examples above are simplified to give you the overall idea. When
deciding on an experimental hypothesis you need to give some indication
of the method to be used. For the above experiment it might be:
‘Duration of
STM, as measured by the Brown-Peterson technique, will decrease with
age.’
The null
hypothesis would normally read:
‘Age will
have no affect on duration of STM. Any effect found could be due to
chance.’
Why do we
have a null hypothesis?
A null
hypothesis is easier to prove. For example if we were trying to show
that all MZ twins had the same voting intentions. Our hypothesis might
be:
‘Pairs of MZ
twins will always vote in the same direction in the coming General
election.’
The null
hypothesis might be:
‘Twins
status will have no affect on direction of voting. Any similarity found
may be due to chance.’
Suppose we
test 50 twins and both members of each pair are intending to vote in the
same direction. Have we proved that all twins will vote in the same
direction? It could be that the next pair we test won’t. In that case
all we need to do is find one pair that have different intentions to
prove our null hypothesis.
When we
finally get round to testing the results with a stats test it will be
the null hypothesis that we’re testing.
One
tailed or two tailed?
Having
decided on your hypothesis and aims you need to decide on the
direction. In the examples above I’ve already done this.
When we say
that we expect ‘duration of STM to decrease as age increases’ we
are making a definite prediction. That prediction has direction.
Compare this to the statement that ‘duration of STM will be affected by
an increase in age.’ Will duration increase or decrease? The
hypothesis doesn’t say. It could go either way.
One tailed
If the
hypothesis has a direction we say it is ‘directional’ or one-tailed. In
the first example we are saying that duration of STM will decrease.
Two tailed
If we are
not prepared to commit ourselves and simply say there will be an affect
then this is non directional or two tailed.
Try the
exercises for practice and further illumination.
In year 13
coursework you will almost certainly be copying (sorry replicating)
someone else’s work, for example Peterson and Petersons. In this case
your hypothesis will be based on their research. If you were to
replicate Milgram’s (don’t even think about it), you would choose a one
tailed hypothesis such as:
‘Participants will follow instructions and fry an innocent person with
450V of electricity when told to do so by a man in a white coat.’
You could
predict this with some confidence since all past research suggests that
this is the case.
Note: this
business of one or two tailed does not apply to the null hypothesis.
This will always read, “not be affected” or “no correlation” etc.
Selecting
your victims (sorry participants)
Having
decided on your method (experiment, correlation etc.) and your design
(repeated or individual) you now need to decide how you will choose the
people who will be assigned to your conditions or groups.
When asked,
everyone replies in unison (not the Trades Union): ‘RANDOMLY.
WRONG!!!
Random
Sample
It is
practically impossible to get a truly random sample. In a random sample
every member of your target population would have an equal chance of
being selected. So for example if you wanted a random sample of primary
school children in the Market Harborough area you would need to obtain
all of their names, put them in a hat and draw your sample out.
In actual fact that would be the easy bit. The difficult task would be
finding them and persuading their parents to let you chosen ones take
part!
The main
disadvantages of this method are:
1.
Time
consuming
2.
Inevitably some of those selected will not take part
Other, more
realistic methods of obtaining a representative sample:
Systematic
sample
(similar to
random, with the same disadvantages)
This could
be done by visiting the target schools and selecting every 5th
child in the register. This would still be time consuming. If your
target was people in MH, you could select every 20th street
and then visit every 10th house in those streets etc.
However, it cannot be claimed that every person in MH has an equal
chance of being selected!
Stratified
sample
Here each
variable affecting the outcome of the procedure needs to be considered.
For example if you were investigating voting intentions you would want
to select on grounds of: gender, occupation, age, education, home
ownership etc. So because the male:female ratio is about 50:50 your
sample would be 50:50. Because about 65% of the adult population are
home owners then 65% of your sample would be too. Etc., etc.
Disadvantages
Time
consuming
Not a truly
representative sample
Opportunity
sample
Now we’ve
hit rock bottom! This is probably the least effective way since it
involves selecting whoever happens to be available and willing to take
part!
Next year in
your search for victims, chances are you’ll go to the sixth form centre
and pick out a few friends or non-threatening strangers. Valentine
(1982) estimates that 75% of all American and British psychology
research is conducted on students, and the majority of these will have
been selected in this way!
Disadvantages
A very poor
representative or cross-sectional sample!
Sample Size
How many
people are going to be part of your opportunity sample?
Things to
consider:
Large
samples can be expensive and are definitely time consuming
Small
samples make it difficult to get a significant result (20 is about the
minimum for most statistical tests).
Generally,
the larger the sample the better since bias is likely to be reduced.
Reliability
and Validity
Both of
these have been mentioned during the year, particularly ‘validity’ as in
‘ecological validity’ or ‘experimental validity.’ However, you now need
to fully understand what both of them mean, how they can be increased
and most importantly how to remember which is which!
Reliability
Reliability
is akin to consistency
If you use a
meter rule to measure the length of your classroom today, and you repeat
the procedure next week, you will expect to get the same result. The
meter rule is consistent in its measurement or we say it is reliable!
Reliability
in Psychology
This can be
measured in a number of ways depending upon the circumstances. However,
each time we are looking for consistency of measurement:
Reliability
of observations
This year
some of the students have observed aggressive acts in men’s and women’s
football to see if the men’s game is really more aggressive.
(Personally I never realised that real men played football but that’s a
different issue).
Inter-rater
reliability
One way of
tackling this problem would be for one person to watch a game played by
each gender, look for various aggressive acts and score them
accordingly. However, you only have one person’s opinion. Better would
be to get two or three people to do it independently and compare scores
afterwards. To ensure that results were reliable the raters would sit
down beforehand and decide on the criteria to use and how to apply
these. For example decide exactly what was meant by ‘dirty tackle’ (no
jokes please) or an ‘aggressive act.’ This would ensure inter-rater
reliability. Or in English it would ensure consistency in measurement
between the observers. All singing from the same hymn sheet in
politico-speak.
Reliability
of tests
If you
measure someone’s IQ today you would expect to get a similar result if
you used the same test to assess the same person in a few weeks time.
If the results were the same time (i.e. if the results were consistent
(that word again)), you could assume the test was reliable!
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Split test reliability
Rather than waiting a few weeks to try the test again it is
possible to use split test reliability. For example with an IQ
test, split it in half give both halves to the participant and
compare their score on each separate half. If scores on each
half are similar psychologists assume the test to be reliable.
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Validity
Does the
test or the experiment measure what it’s s’pose to be measuring?
We have
mentioned this word ‘validity’ on a number of occasions, usually in
relation to ‘ecological validity.’ However, there are a number of
different types of validity; here we’ll concentrate on ‘internal’ and
‘external’, sometimes referred to as ‘ecological.’
Internal (or
experimental) Validity
Are the
effects that have been caused actually due to the independent variable?
For example if we’ve found that coffee (the I.V.) does increase speed of
reaction (the D.V.), can we be certain that this increase is really due
to the coffee or could it be due to a confounding variable such as the
time of day or just faster reactions of the second group etc.
Basically
any of the confounding variables mentioned so far such as IQ, gender,
age, time of day, lighting conditions etc., can cause false conclusions
to be drawn.
External
validity (like ecological validity)
How much can
the results obtained tell us about real life, or put another way; can we
generalise our findings to the real world?
Coolican
(1994) points out 4 major issues:
-
Population:
Can we generalise from our small sample, probably all students, to
the population as a whole?
-
Location, location, location
(Coolican only said it once): Can the results that we’ve obtained in
a laboratory setting really tell us how people will behave in real
life. Think back to memory experiments most of which were carried
out in laboratories, or to ‘Stan the Man’ Milgram’s experiment in
the labs of Yale University. Would people really behave this way in
real life?
-
Measures:
If we use the Eysenck Personality Questionnaire (EPQ) and measure a
person as very extrovert and slightly neurotic, can we be sure that
they are really like this in real life or in social situations?
Similarly when we measure IQ, is the test we are using telling us
anything real about the person?
-
Times:
Can
experiments carried out 40 0r 50 years ago such as Asch, Milgram
etc. still tell us anything about people today. I have mentioned
how for example conformity changes over time. Wars, for example
tend to bring populations together and make us more conformist as
was measured following the Falklands Conflict of 1982.
Methods of
checking validity
Clearly it
is useful for a psychologist to have some idea of whether or not tests
are valid. There are a number of ways this can be done:
Meta
analyses:
data can be
collected form lots of different studies in different parts of the World
and see if results are similar. For example Bouchard & McGue compared
findings for IQ tests between MZ twins and found similar levels of
correlation between them all.
Concurrent
validity:
if we are measuring IQ we could compare the scores obtained to school
tests in maths and English, or we could compare the results of
personality tests with assessments by a person’s friends and family.
Predictive:
a test should be able to predict later performance, behaviour or
personality. So again, a high score on an IQ test should be able to
predict later success at school etc. In school you sit YELLIS and ALIS
tests which are used by teachers as predictors of your future
performance.
Relationship
between researcher and participant
As we’ve
already seen this can cause problems, particularly in the experimental
method. In the Milgram evaluation I touched on demand characteristics,
the idea that simply because the participant was taking part in an
experiment that this would affect his behaviour (all Milgram’s
participants were ‘he’s).
Possible
effects:
Participant
reactivity
Put simply,
participants will behave differently or unnaturally because they know
they are being watched. This doesn’t just apply under experimental
conditions but in any walk of life! The classic example which is well
worth a read, but not necessary for the exam, is to be found on page 272
and is known as the ‘Hawthorn Effect.’
Demand
characteristics
The idea
that participants will behave the way they believe you want tem to
behave. It could be that participants guess what the experiment is
about, or at least think they’ve guessed, and this will influence their
behaviour accordingly.
This was a
criticism of the Milgram procedure. In Asch’s study on conformity, some
of the participants said afterwards that they conformed because they
didn’t want to mess up the experiment!
Orne (1962)
persuaded participants to do strange, if not very foolish things. This
argument is often used in the debate over hypnosis. Orne, for example,
persuaded his participants to put their hands into a tank containing a
supposedly very venomous snake. His most famous ‘experiment’ was to
persuade participants to spend hours adding up random numbers and then
getting them to tear up all their hard work!
Sometimes,
of course, the reverse may be true, and for whatever reason, e.g. having
been conned in previous studies, participants may deliberately seek to
mess up your experiment by behaving counter to how they think you want
them to behave.
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People can be persuaded to behave in the most bizarre and
unnatural ways just because someone asks them to.
This doesn’t mean that they’d behave that way in real
life.
Of
course money or the promise of publicity goes a long way too!
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Reducing
demand characteristics
The most
common ploy is called the single blind technique in which participants
are not told details of the study or in which they are led to believe
it’s about something different. This is a ploy I used in my research on
hypnosis. (Will bore you with the details sometime soon!).
Clearly this
raises ethical issues such as deception and informed consent.
Investigator
effects
A
confession. As a sixth former, many years ago, I spent, what seemed at
the time, about five years doing titrations in A-level chemistry. Not
one of the results I obtained was genuine. We calculated the ‘right
answer’ for all of them and then obtained a reading that was close to
this. This was cheating, and we know that results in Psychology have
also been fiddled, some on a grand scale. Obtaining ‘expected results’
like this can be deliberate. Or it can happen without intent. We often
find what we are expecting or hoping to find. Having decided that women
are worse drivers we notice bad driving by women whilst ignoring similar
driving by men. This happens in research and is called experimenter
expectancy. The classic example is Rosenthal and Lawson (1964). They
gave rats to students, telling some that their rats were ‘maze bright’
and could navigate a maze very quickly, and telling others that their
rats were ‘maze dull’ and not very good at navigating a maze. In fact
the rats were all similar and allocated to each group of students
randomly.
From what
I’ve said, you can probably guess the findings: Students with the
supposedly maze bright rats found that their rats could navigate mazes
significantly faster!
Reducing
experimenter effects
The most
common ploy is called the double blind technique, in which neither the
participants nor the researchers dealing with the participants know the
conditions etc. Obviously someone distant from the procedure still
needs to know which participants are in which condition so that results
can be analysed! This procedure is commonly used in drug testing when
genuine medicines are compared to placebos.
Remember
that on top of this there is the 'data analysis' section, which involves
some number crunching. See contents page for details. However, the
worksheets provided in lessons should cover this are in sufficient
detail so I'll skip notes on this and concentrate on conformity
instead. Hope this has not been too heavy a read, I've tried to keep it
brief and to the point!
Planning
and Reporting your Practical Report
All
psychological investigations are written in a common format whether they
are GCSE, A-level, degree level or professional research. You
may also find similarities with other subjects such as Biology.
Psychologists usually publish their research in Journals such as The
British Journal of Psychology. Their main purposes are to make other
interested parties aware of their methods and findings and crucially to
provide sufficient detail to allow for replication. It is essential
that others can check the reliability and validity of the methods and
results. Typically a published article has the following structure. I
shall consider each aspect in turn and explain its contents and format.
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Title
Contents
Abstract (Summary)
Introduction:
Background research
Aims/Hypotheses
Method:
Design
Participants
Materials/Apparatus
Procedure
Control
Results:
Summary-and Descriptive Statistics
Inferential Statistics
Discussion:
Explanation of findings
Relationship to background research
Limitations and modifications
Implications and further research
Conclusion
References
Appendices |
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|
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TITLE
The title
should be concise yet clear enough to give the reader an idea of the
investigation's central concerns. 'Memory study' would be too vague
whereas 'Testing the Passive Decay Theory of Forgetting from Short-Term
Memory using a task similar
to that employed by
Peterson and
Peterson (1959)' would be for too long. Best also avoid titles which
start 'An investigation into...' or 'A study of...'.
General
Points
When writing
up a report try to be concise yet precise. Include everything relevant,
but do not take 8 pages to describe something that could be explained in
a paragraph or two. Remember that your investigation should have enough
information in it for someone else [maybe a few years later] to
replicate it exactly, so you need to include sufficient detail.
Write in the
third person passive. In other words do not say 'The participants will
be...' say 'The participants were...'.
Write it up
as if you were describing someone else's experiment that took place last
week, and you were not actually there. Do not say 'our experiment...',
'I calculated...' or 'we noted...' but say 'the experiment...', 'it was
calculated...' or 'it was noted...'.
Include page
numbers at the foot of each page.
Do not
forget to report ethical aspects of a study where appropriate, such as
consent, right of withdrawal, confidentiality and protection from harm,
etc.
Your report
must be written in your own words. If you present a report which
contains material either copied from books, handouts or other student's
work, this is PLAGIARISM and would make you no better than Alastair
Campbell!
Now let’s
turn to the write up itself:
Introduction, Aims & Hypotheses
·
This
contains the background to your report and should be planned and written
like a mini essay. Crucially the introduction explains where
your hypotheses come from.
·
Start with
general theory, briefly introducing the topic. Talk about other
psychologists’ research in the area. It is all too tempting to throw in
all the really interesting material you have found during your extensive
research of the topic, be concise and selective. Only include material
that really is relevant.
·
Narrow this
down to specific and directly relevant research. If you are planning a
replication or adaptation of an existing study then give sufficient
detail about this.
·
Lead
logically into the aims and hypotheses. In the old days of coursework,
marks were awarded for a logical progression. Basically think of the
traditional ‘V’ shape of an athlete.
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Start broad at the shoulders with an overview of the general
topic area, for example research into STM and LTM.
Then gradually home in ‘missile-like’ to the crucial
study that you will be investigating, for example a serial
recall task investigating the capacity of STM.
This would be down by the waistline if we extend my
initial metaphor.
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·
Aims should
not appear out of thin air. The psychological literature that you have
reviewed should lead up to the aims.
·
A paragraph
should be written explaining what you intend to investigate and why.
Use previously cited research to explain your expectations. Later these
expectations will be formally stated as the hypothesis. Include a
justification for the direction of the hypothesis explaining why you
have decided on a one or two tailed.
·
Hypotheses: should be written in the present or future tense (remember
you are making a prediction). They should be fully operationalised,
stating precisely what is to be manipulated or measured. (e.g. instead
of talking about the ‘participant’s memory, talk about ‘the number of
words recalled,’ since this is how you will be measuring the
participant’s memory).
·
State the
minimal level of significance that will be acceptable (usually 5%) and
why you have chosen this level.
Method
This is just
a section heading. The section has several sub-sections, and there are
no hard and fast rules about what information goes where, providing you
use a little common sense and try to avoid repeating yourself and you
try to avoid repeating yourself!
The purpose
of the whole section is to inform the reader precisely how the
investigation was undertaken. The acid test is whether or not the
reader would be able to replicate your research precisely, just by
reading your description. The section should also demonstrate that you
have taken ethical issues into consideration when designing your study.
You should use the third person when describing the method. E.g. ‘it
was decided’ rather than ‘I decided’ or ‘we decided...’ And try to
avoid repeating yourself
J
Design
Describe any
design decisions made, for example:
·
Choice of
method, e.g. field experiment, observation etc.
·
Choice of
experimental design e.g. independent or repeated measure, or matched
pairs
·
Identification of variables: I.V., D.V. or if your method is
correlational describe your co-variables.
·
Identify any
confounding variables (e.g. participant characteristics, order
effects). Explain attempts to be made to overcome confounding variables
(e.g. counterbalancing, standardisation of instructions).
·
Ethical
considerations.
·
Identify the
level of data (e.g. ordinal) and the statistical test you will use
together with the level of probability for retaining the null
hypothesis.
Participants
Include the
number employed and how they were sampled. Include any factors that are
relevant to your study such as age, gender, education level etc. When
you mention participants be careful not to give away clues as to their
identity.
Consider
treatment groups and how participants were allocated to their respective
groups (i.e. how did you decide which participants were to be in the
control group and which were to be in the experimental). NB If you are
comparing boys to girls or different age groups then this is decided for
you!
Ethical
issues
You must
protect your participants confidentiality and therefore all must
remain anonymous. To the same end do not even mention the name of
the school!
If you
use minors (i.e. under 16s) then you need to state how you obtained
permission for them to take part in the study.
Materials/Apparatus
The materials and apparatus used such as questionnaires
should be described here. You need to include sufficient detail so that
it is clear how they were compiled. The reader requires enough detail
to be able to reconstruct the materials. Do not be overly patronising
and mention detail such as pens being required to fill out the
questionnaires! All questionnaires etc. should be referenced accurately
to the appendix. Remember to include any mark schemes for
questionnaires used.
Procedure
This section should be written in the past tense since
you are reporting what you did. You need to state precisely what you
did with the apparatus and the participants. The rule is simple,
describe what you did in sufficient detail for your study to be
replicated, including any preliminary work or pilot studies undertaken.
Any standardised instructions or debriefs should be referred to and a
justification for their use included. Include a copy of these in the
appendix.
If you have scored any questionnaires or ranked
categories such as GCSE subjects in terms of science or verbal content
then you need to say how this was carried out.
Ethical issues
It is vital that your participants
are fully debriefed after the testing phase is completed. This is
particularly important if any deception has been used. A
standardised debrief can be used and this must be checked by a
member of staff.
All participants should be informed
that data will be kept confidential and given the right to withdraw
from the investigation and assured that their data will not be used.
Collecting
your data
Once you
have planned your research, written your introduction and method and
have had your ideas and materials checked by your coursework supervisor,
you are ready to carry out your procedure and collect your data.
Remember to give yourself sufficient time - don't expect to get it all
done in one private study period!
Hint:
Always
make a note of anything that happens in your INVESTIGATION LOG BOOK,
no matter how inconsequential it may seem at the time. A casual
comment made by one of the participants may turn out to be the key
that explains why your study produced the strange results it did.
Some things are too obvious and can often be overlooked because they
are under our noses! Note everything, record everything, and think
about the effect it may have had on your data.
Important
points to remember when carrying out research:
Ensure that
you are fully au fait with the ethical guidelines as laid down by
the BPS.
Ensure that
you are fully comfortable with the procedure and know precisely what is
going to happen and in what order. It is useful to have a dummy run of
your procedure before ‘going live.’ Ask a few friends to act as
participants and ensure that you haven’t overlooked any details.
Generally
speaking any instructions given should be standardised and preferably
presented in writing. This way you can be certain that all participants
are given precisely the same instructions.
Always
inform participants of their right to withdraw from the procedure at any
time if they so wish.
Always be
courteous with participants and act in a professional manner.
Always carry
out a ‘debrief’ at the end of the procedure. Again this is best written
to ensure that nothing is forgotten and should inform participants of:
The exact
nature and point of your study
Their right
to withdraw their data from the study
Their right
to see the final write-up once it has been completed.
Be polite
and thank your participants for taking part in your research!
Copies of
both the ‘standardised instructions’ and the ‘debrief’ should be
included in the appendices of your final write-up.
Results
This section
is where you summarise your data and provide a report on any statistical
analysis that you have carried out. Clarity is all important in this
section so you need to find concise and informative ways of presenting
data.
Note: all
raw data should go in the appendix and be referenced.
Descriptive (or summary) statistics.
These are
every bit as important as inferential. The purpose of this section is
to describe what you have found and give the reader ‘a feel’ for the
data. This can be done in the form of averages, standard deviations,
tables, bar charts, scattergrams and graphs.
Special care
should be taken that all graphs etc. have titles and appropriately
labelled axes. All such graphs should be self explanatory, it should
not be necessary to refer to the text to make sense of them.
Keep graphs
etc. simple. If more complex or multiple graphs are used put these in
the appendix and make reference to them in the results section. Try to
avoid death by a thousand graphs!
Tables,
graphs and other figures should be consecutively numbered.
Be sure to
explain what the obtained data shows in the text.
Inferential Statistics
These are
used to tell us the likelihood of the hypotheses being true, i.e. what
are the chances that the results we have obtained may have occurred by
chance alone.
Begin by
stating what test was done and why! Refer to the research design
(repeated measures etc.), level of data (ordinal etc.). Most
importantly were you looking for a difference or relationship. You need
to fully justify your choice of test.
In your
write up you will need to include the value that you have calculated
(the observed value). This needs to be compared with the
critical value, which is the value you look up in a table. These
can be found in the back of most psychology text books.
Does this
show that your results are significant or not for that number of
participants, at the stated level of significance for either a one or
two tailed hypothesis?
All
calculations should be included in the appendix.
Do not put that type of dull information in the main body of the report!
Discussion
AQA like
this split into the following four subsections:
Explanation of Findings
This sounds
like a repeat of the results section, but here you need to state what
you’ve found in terms of psychology rather than in statistical terms, in
particular relate your findings to your hypotheses. Mention the
strength of your findings, for example were they significant and at what
level. If your hypothesis was one tailed and your results have gone in
the opposite direction this needs to be indicated. If you have any
additional findings to report, other than those relating to the
hypotheses then they too can be included.
A word
of warning: avoid the use of words such as ‘proves’ or ‘disproves.’
This is Psychology, there are few, if any hard facts. ‘Suggests’ or
‘indicates’ are better alternatives. Each year students insist on
reporting that their research carried out on an opportunity sample
of eight year five pupils disproves Piaget, a well respected
figure in the area who spent fifty or more years of his life testing
thousands of children!
Relationship to background research
If your results agree with previous
studies then this section may be brief, but there may still be ways in
which your findings differ in some way. If your results run counter to
previous studies then you need to make this clear and try to explain the
discrepancy.
Limitations and Modifications
Consider how your findings may have been influenced by confounding and
extraneous variables (i.e. factors other than the one you were
testing).
If you got the result you expected, can you be sure of what made this
happen? Look at the method for possible confounding variables that
could have caused a type one error. Consider whether any aspects of the
study were unsatisfactory. Believe me, no matter how careful you have
been, you will not have carried out the perfect study. How many pieces
of research have you come across in Year 12 that were perfect? For
example were the participants entirely honest in their responses? Were
there any experimenter effects? Was the sample size or method of
selection adequate?
Comment on the statistical procedures used, particularly the power and
sensitivity of the test. Chances are you have had to use a non
parametric test which are not as powerful as their parametric
alternatives.
Having
mentioned the limitations of your research be sure to include how you
could improve it. This section is titled ‘limitations
and modifications.’ All too
often students only discuss the shortcomings.
Implications and suggestions for further research
This is not asking you to repeat the previous section! Finally you need
to discuss how relevant your research findings are to real life. Think
of any practical applications of your findings. Also, how could you
follow up the research to find out more. This is different to
modifications discussed in the previous section. You will probably be
up to your word limit by now so only a couple of suggestions are
required!
Having
completed their discussion many students assume that all is done. To be
fair all of the hard work is now over but there are still a few
vital sections to consider.
Abstract
Although this appears at the front of the report
it is the last section to be written. The purpose of the abstract is to
tell the reader the bare essentials of the research you have carried
out. The style should be brief, but not in note form.
Include a
one sentence summary, giving the topic to be studied. This may include
the hypothesis and some brief theoretical background research, for
example the name of the researchers whose work you have replicated.
Describe the
participants, number used and how they were selected.
Describe the
method and design used and any questionnaires etc. you employed.
State your
major findings, which should include a mention of the statistics used
the observed and critical values and whether or not your results were
found to be significant, including the level of significance
Briefly
summarise what your study shows, the conclusion of your findings and any
implications it may have.
Example:
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Office-Based Treatment of Opiate Addiction with a
Sublingual-Tablet Formulation of Buprenorphine and Naloxone.
Fudala et al 2003
Background Office-based treatment of opiate addiction with a
sublingual-tablet formulation of buprenorphine and
naloxone has been proposed, but its efficacy and
safety have not been well studied.
Methods We conducted a multicenter, randomized,
placebo-controlled trial involving 326
opiate-addicted persons who were assigned to
office-based treatment with sublingual tablets consisting
of buprenorphine (16 mg) in combination with naloxone (4
mg), buprenorphine alone (16 mg), or placebo given
daily for four weeks. Safety data were obtained on
461 opiate-addicted persons who participated in an
open-label study of buprenorphine and naloxone and
another 11 persons who received this combination only during
the trial.
Results The double-blind trial was terminated early because
buprenorphine and naloxone in combination and
buprenorphine alone were found to have greater
efficacy than placebo. The proportion of urine
samples that were negative for opiates was greater in
the combined-treatment and buprenorphine groups (17.8
percent and 20.7 percent, respectively) than in the placebo
group (5.8 percent, P<0.001 for both comparisons); the
active-treatment groups also reported less opiate
craving (P<0.001 for both comparisons with placebo).
Conclusions Buprenorphine and naloxone in combination and
buprenorphine alone are safe and reduce the use of
opiates and the craving for opiates among
opiate-addicted persons who receive these medications
in an office-based setting.
|
References
This section should be straightforward provided
the following guidelines are adhered to. However, every year students
drop one mark, or even both, because they think they know better! The
references should contain details of all the research you have covered.
It is not sufficient (as below) to simply list the books used!
What not
to do:
A New Introduction to Psychology, Gross
& McIlveen
Bluffers Guide to Psychology, Uddin,
Rice and Moss
This is a list of books, or a bibliography.
What you
should do:
Look through your report and ensure you include
every researcher mentioned.
For each one provide information on where that
particular study was originally published, for example:
Paivio, A., Madigan, S.A. (1970). Noun
imagery and frequency in paired-associate and free learning recall.
Canadian Journal of Psychology. 24, pp353-361.
This is the researchers and year, the title of
their publication, the journal in which it was published with volume
number and specific page references.
Other rules:
The references
should be in alphabetical order, not the order in which they appear in
your report. See how it's done in the back of the set texts.
In the unlikely
event of the same researcher having two reports, both in the same year,
use 'a' and 'b' to separate them out, e.g. Waring (1962a) and Waring
(1962b).
Sometimes the
text books are naughty and do not provide a reference for a piece of
research they've mentioned. In this case you have one of two options:
a.
Look it up in another text
book or
b.
If that fails use the
following format:
Freud, S. (1922) cited in Gross RD
(1996) The Science of Mind and Behaviour (3rd Edition). London: Hodder &
Stoughton.
This is the
researcher and year, the text book in which you found the information,
where the book was published and the name of the publishers.
Hint: As I
mentioned earlier it is all too common for students to reach the end of
their report and realise that they can't remember where they found a
particular reference. Write them down as you go along, preferably in
your log book, but also anywhere else where you won't lose the
information.
ALL AUTHORS MENTIONED MUST BE
REFERENCED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Choosing the correct Statistical Test
An
important point to consider at the outset, particularly those amongst
you that don’t like sums. You will not be expected to calculate a level
of statistical significance. However, you will need to know when to use
a particular test and also having been given an observed value, be able
to decide its level of significance. This isn’t as complex as it
sounds. It’s simply a matter of looking up the information in a table,
though you will need to understand what the table tells us!
When choosing a test there are three things to consider. Two of these
have already been covered in this booklet, the third was covered at AS
so a quick reminder.
1.
NOIR: What is the level of your data?
Nominal Data:
is the simplest thing a number can do. It can tell us how many things
there are! Basically nominal data is a headcount or a tally. It
doesn’t tell us if something is bigger, brighter or bolder, just how
many. For example, get a show of hands; how many people in the class
study English. Your head count provides nominal data. If you were
replicating Piaget’s research at a primary school you might count the
number of five year olds who can successfully complete the three
mountains task and compare this to the number of seven year olds.
Nominal data.
Ordinal data:
allows us to put things in order. For example A might be more
attractive than B but uglier than C. We have the order C A B in terms
of attractiveness. Crucially however, we can’t be sure that the
difference between C and A is the same as the difference between A and
B. C and A might both be very attractive whereas B might be a complete
minger. We can’t tell that the intervals are the same.
Usain Bolt won the men’s 200m at Beijing, Shawn Crawford was second and
Walter Dix third. From this we can’t tell is the difference between
first and second was the same as the difference between second and
third. First, second, third provides ordinal data.
Interval and Ratio:
allows us to put things in order (ascending or descending) just as
ordinal, however this time we can be sure that the intervals are the
same. We know that the difference between 10cm and 11cm is the same as
the difference between 15cm and 16cm. The same applies to weight or
mass, temperature and time.
An
odd one to consider is IQ. The jury is out on this one. Some
psychologists believe it yields interval/ratio data, others that it is
merely ordinal.
Generally speaking if you need a piece of equipment to measure it, then
its interval or ratio.
For
the purposes of statistics interval and ratio are taken as the same.
There is however, a subtle difference. Ratio has a true zero. So no
minus values, e.g. time, weight, height. Interval data can be minus
e.g. temperature in degrees Celcius. As a result you can say that 20cm
is twice as long as 10cm. You cannot say 20C is twice as hot as 10C.
2.
Correlation or difference?
Provided you’ve given careful consideration to your procedure and are
confident tin what you’re looking for this should be easy. Some groups
have appeared confused in the past, particularly with issues such as the
relationship between attractiveness and punishment. This could be done
either way:
You
could produce an ascending scale of attractiveness and compare this to
the level of punishment given to each person. You would predict a
negative correlation; as attractiveness increases, level of punishment
given decreases.
Alternatively you could split your photographs into two groups, with the
beautiful people in one group and the mingers in the other. Then count
the level of punishment offered for each. You are now looking for a
difference between the two groups. The danger is, having formulated a
hypothesis that you don’t stick to it.
Generally however, it should be obvious from your hypothesis what you’re
looking for!
3.
Repeated or independent measures design
Again obvious since we’ve covered it many times. If you’re using the
same group of participants to assess both variables its repeated
measures. If the participants in one condition differ from the other
its independent. There are times when the decision is made for you.
Sex differences, age differences, cultural differences… they have to be
different participants in each condition.
Decision time
Having decided on the above three dimensions, use the chart below to
decide which test to use. You will be expected to know about the four
in bold: Chi squared, Wilcoxon’s sign test, Mann-Whitney ‘U’ and
Spearman’s ‘rho.’
|
|
Test of
|
difference |
Test of
correlation (relationship) |
|
Type of
Data |
Repeated
Measures / matched Pairs |
Independent measures / single participant |
|
|
Nominal
|
Sign Test |
Chi
Squared |
Chi
Squared |
|
Ordinal |
Wilcoxon sign test |
Mann
Whitney ‘U’
|
Spearman ‘rho’ |
|
Interval/
ratio |
Related
‘t’ test |
Independent (unrelated) ‘t’ test |
Pearson
product moment (‘r’) |
e.g. if you have ordinal data with independent measures design and
you’re looking for a difference, you will use Mann-Whitney ‘U.’
Now
a little bit of play acting or imagination. Let’s pretend you’ve done
your experiment, collected your raw data, chosen the correct test to use
and made your calculation. All your numbers will have been put into
tables or grids, you’ll have calculated means and added things up,
squared and square-rooted, subtracted one group from another and perhaps
done some dividing too. At the end of this you’ll have calculated ONE
number. This number will magically tell you whether your results are
meaningful and statistically significant, or whether they’ve more than
likely occurred by chance and are little more than a fluke.
Critical and observed values
The
number you calculate is your observed value. This needs to be compared
with the critical value in the appropriate table. Each test has its own
table with various critical values depending on the level of
significance 5% (0.05), 1% (0.01), 0.5% (0.005) and so on. The critical
value also varies depending on the number of participants or degrees of
freedom.
With Spearman’s rho and chi squared tests the number you calculate needs
to be equal to or greater than the critical value for your findings to
be significant.
Aide memoire
‘Spearman’s rho’ and ‘chi squared’ both contain ‘Rs’ as does the word
gReater
‘Mann Whitney U’ and ‘Wilcoxon’s sign’ do not contain R. With these two
tests the critical value needs to be equal to or smaller than the
critical value.
Type one and type two errors
Type 1
This is believing you have found a significant result when you haven’t.
You reject the null hypothesis when it should be retained. For example
you might set too lenient a level of significance.
Type 2
You’ve guessed it… this is believing you have found nothing of
significance when you have. This one is particularly annoying for an
undergraduate piece of research. You have accepted the null hypothesis
when it should have been rejected. This could happen if you set
yourself too high a level of significance.
|
Chi squared test
Use when you have nominal data with independent measures
design. Unlike the other tests, chi-squared can be used to test
for a correlation or a difference.
For example: Piaget’s three mountains test:
|
|
5 year olds |
7 year olds |
Totals |
|
Successful |
a.
4 |
b.
18
|
22 |
|
Not successful |
c.
16
|
d.
2 |
18 |
|
Total |
20 |
20 |
40 |
You would put your raw data into a grid and then calculate the
expected frequencies for each cell (a,b,c,d)
You then compare the scores you obtained with what would be
expected by chance. With some appropriate and very repetitive
number crunching (especially if you have 20 cells) you calculate
your critical value.
The chi squared test uses degrees of freedom calculated:
Number of columns -1 x Number of rows -1
In this case 2-1 x 2-1 = 1 x 1 = 1
You look up your observed value in the appropriate table for 1
degree of freedom at the 5% level.
Your number needs to be equal to or greater than the critical
value.
|
If
asked to justify a choice of test do so in terms of whether you’re
looking for a correlation or a difference, using an independent or
repeated measures design and level of data obtained.
For
example: I chose to use Mann Whitney ‘U’ because I was looking for a
difference with an independent measures design and would be obtaining
data at the ordinal level.
Note: if using matched pairs design treat as repeated measures.
|
Spearman’s Rho
Use when you are looking for an association (for example a
correlation) with ordinal level of data.
For example, testing the matching hypothesis which predicts that
men and women with similar levels of attractiveness are more
likely to get married.
This time you put your raw data in a table that looks like this:
|
Couple |
Groom |
Bride |
Rank
(groom) |
Rank
(bride) |
Difference between ranks |
Difference squared |
|
A |
4 |
5 |
|
|
|
|
|
B |
4 |
4 |
|
|
|
|
|
C |
9 |
8 |
|
|
|
|
|
D |
2 |
10 |
|
|
|
|
|
E |
7 |
7 |
|
|
|
|
|
F |
8 |
8 |
|
|
|
|
|
G |
3 |
4 |
|
|
|
|
|
H |
8 |
9 |
|
|
|
|
|
I |
6 |
6 |
|
|
|
|
|
J |
4 |
5 |
|
|
|
|
|
|
|
|
|
|
|
|
You can complete the rest when we look at ranking a set of data.
Essentially you give each groom a rank dependent on their
attractiveness compared to the other grooms and then repeat the
process for the brides. The higher the correlation the more
similar the two sets of ranks (i.e. the more similar their
levels of attractiveness. When you calculate the difference in
ranks the more similar the attractiveness the smaller the
differences. You square the values to get rid of any negative
values (remember -2 squared is 4 not -4!).
After a little more jiggery pokery you end up with a critical
value… this time always between -1 and +1.
You look it up in the appropriate table. This time the number
of pairs is important. There is a critical value at 5% that
varies depending upon the number of pairs of participants. Your
observed value needs to be gReater than or equal to the critical
value.
|
|
Mann Whitney ‘U’ Test
Use when you are looking for a difference with ordinal data and
an independent measures design.
For example you might want to test the hypothesis that boys and
girls take different subjects at A-level, boys preferring
spatial and mathematical, girls preferring subjects that are
more verbal.
To do this you allocate a score for each A-level subject…for
example allocating spatial and mathematical subjects a low
score: physics and maths (1), chemistry (2) etc and verbal
subjects a high score English, French, German (10), politics and
history (9) and so on…
You put your raw data in a table that looks like this:
|
Boys scores |
Girls scores |
Rank (boys) |
Rank (girls) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Σ |
|
Unlike correlational (Spearman’s) the boys and girls can go in
any order… this is independent measures so there are no pairs as
such. Also, unlike Spearman’s the number of boys and girls
scores can be different. You could have 10 boys and 12 gorls
for example.
This time you rank all the scores together… place all the boys
AND girls scores in ascending order and calculate a rank. For
the calculation you only need to add up one set of ranks, in
this case the boys. Then following some other number crunching
you end up with TWO values. The smaller value is called ‘U’ and
the larger value ‘U’’ (pronounced U prime).
You check U (smaller number) against the critical value for the
number of participants in each column. This time the observed
value needs to be equal to or smaller than the critical value.
|
|
Wilcoxon’s sign test
Use when you are looking for a difference, with a repeated
measures design and ordinal data.
For example investigating the Mozart effect. This is the idea
that listening to the music of Wolfgang Amadeus Mozart (his real
name was
Johannes Chrysostomus Wolfgangus Theophilus Mozart) but I digress, will improve all
manner of cognitive functions. This could be tested using a
repeated measures design. Day 1 you get your participants to
complete a memory task whilst listening to a popular
contemporary instrumental track. Day 2 they return and complete
a similar task listening to Mozart.
Obviously a better design option here is then to deploy
counter-balancing measures or ABBA if you prefer.
Raw data would go on a table like this:
|
Participant |
Mozart |
Non-Mozart |
Difference |
Rank |
|
A |
|
|
|
|
|
B |
|
|
|
|
|
C |
|
|
|
|
|
D |
|
|
|
|
|
E |
|
|
|
|
|
F |
|
|
|
|
|
G |
|
|
|
|
|
H |
|
|
|
|
|
I |
|
|
|
|
|
J |
|
|
|
|
|
|
|
|
|
|
Any ‘0’ ranks are ignored. The sum of positive ranks is added
and then the sum of negative ranks. The smaller of the two
values is taken and then it’s a very quick job to look up the
value in an appropriate table for the appropriate number of
participants (in the above case 10). The simplest of all
inferential tests to calculate.
Wilcoxon’s sign test contains no letter ‘R’ so this time the
observed value needs to be equal to or smaller than the critical
value found in the table.
|
|