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Summary AQA A level revision notes for Research methods in psychology
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Very detailed revision notes for research methods for AQA A level psychology that covers everything in the spec
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Research methodsExperimental method
à involves the manipulation of variables to establish cause & effect relationships.
An experiment = an investigation in which a hypothesis Psychologists investigate human
is scientifically tested. behaviour in 2 ways
An IV (the cause) is manipulated & the DV (the effect) • Experimental
is measured, any extraneous variables are controlled. • Non-experimental
Non-experimental methods –
* Observational techniques: where you watch people & record their
behaviour/info about them
* Self-report: where people tell you about themselves through an interview/by
filling in some sort of questionnaire
* Case study: where a person/small group are studied intensely & lots of info is
gathered about them
* Correlational analysis: where 2 pieces of info are collected than analysed to
see if there’s a relationship between them
The research is trying to find out whether a particular factor has an effect on a
specific aspect of human behaviour/mental process.
Independent variable = the Dependent variable = Extraneous variable = variable
variable that’s being the variable that’s hasn’t been controlled for but
manipulated/changed being measured may be affecting the results
Internal validity – refers to whether the Mundane realism = type of
effects observed in study are due to Demand characteristics external validity, tasks have
the manipulation of the IV & not some = when ppts know mundane realism when
other factor (=there’s a causal they’re being observed closely resemble activities
relationship between the IV & DV) & change their common in natural settings.
behaviour because of it Lack MR when task is
artificial & therefore has low
EV
Internal validity can be improved by
Þ Controlling extraneous
variables
Þ Using standardised instructions External validity – refers to extent to which results of
Þ Counterbalancing study can be generalised to other settings (ecological
Þ Eliminating demand validity), other people (population validity) & over time
characteristics & investigator (historical validity).
effects
It can be improved by setting experiments in a more
natural setting & using random sampling to select ppts.
, Types of experiments
Strengths
J easier to replicate as a standardised procedure is used
Lab experiments J high internal validity - they allow for precise control of
extraneous & independent variables, allowing a cause &
à conducted in highly controlled
effect relationship to be established
conditions where accurate
measurements are possible
à ppts are usually aware they’re Limitations
taking part but may not know L the artificiality of the setting may produce unnatural
true aims of study behaviour that doesn’t reflect real life e.g., mundane realism,
à researcher decides where low ecological validity meaning it won’t be possible to
experiment will take place, at generalise findings to real life settings
what time, with which ppts, what L demand characteristics/experimenter effects may bias the
circumstances & using a results & become cofounding variables
standardised procedure L more expensive/time consuming
Strengths
Field experiment J behaviour is more likely to reflect real life (mundane
à done in real life (everyday) realism) as it’s a natural setting, higher ecological validity
natural environment of ppts than lab – so can be generalised
à experimenter still manipulates J less expensive
the IV but can’t control J less likelihood of demand characteristics affecting results
extraneous variables as its real- as people don’t know they’re taking part
life setting
à less likely ppts know they’re in Limitations
experiment L may be ethical considerations
L less control over extraneous variables – makes it difficult
for another researcher to replicate the study
Strengths
Natural experiment
J behaviour is more likely to reflect real life as it’s a natural
setting – high ecological validity à conducted in real life
J less likelihood of demand characteristics affecting results environment of the ppts but
as ppts may not know they’re being studied experimenter has no control over
J can be used in situations in which would be ethically the IV as it occurs naturally in real
unacceptable to manipulate the IV life
J allows psychologists to study ‘real’ problems à conducted when it’s not possible
for ethical or practical reasons to
Limitations deliberately manipulate an IV so
L may be more expensive & time consuming than lab the IV varies naturally but DV may
experiments still be tested in lab
L there’s no control over extraneous variables that might e.g. Hodges & Tizard compared
bias the results – makes it difficult for another researcher to long term development of children
replicate study who have been
L can’t establish cause & effect adopted/fostered/returned to
L if DV measured in lab, may be artificial & demand mothers with a control group of
characteristics children who spent all their lives with
biological families
Quasi experiment
à the IV is also naturally occurring & DV may be tested in a lab.
à the defining feature is that the IV hasn’t been made to vary by anyone – it’s simply a
difference that exists between people e.g. gender/age/Locus of control – the researcher
examines the effect of this variable on the DV – therefore if ppts have different ages & this is the
IV in a lab study, it would be called a quasi-lab experiment
, Experimental design
= how psychologists allocate ppts to different conditions in an experiment
3 experimental designs are commonly used
Independent Repeated measures Matched pairs
groups/measures = testing the same group = testing separate groups of
= testing separate groups of people in different people – each member of 1
of people, each group is conditions – the same group shares a characteristic of
tested in a different people are used a member of other group e.g.,
condition repeatedly social background/age/sex)
Pros Pros
J avoids order effects J ppt variables are Pros
(practice/fatigue effects) as reduced J reduces ppt variables as the
people participate in 1 J fewer ppts needed researcher has paired ppts so each
condition only (saves time) condition has people with similar
abilities & characteristics
J avoids order effects so counter
Cons balancing isn’t necessary
L more people needed than Cons
L may be order effects
with other designs (more time Cons
L fatigue & practice
consuming) L time consuming to find closely
effects
L differences between ppts in matched pairs
group may affect results L impossible to match people
(=participant variables) exactly
L if 1 ppt drops out, you’d lose 2
ppt’s data
L more ppts needed
Ppt variable = how ppts Order effects = refer to the order of conditions having
differ from each other an effect on the ppts behaviour. E.g., performance in
(their individual 2nd condition may be better as they know what to do
(practice effect) or their performance may be worse as
characteristics e.g., age)
they’re tired (fatigue effects)
, Counterbalancing = a technique used to deal with order effects when using a
repeated measures design. The ppt sample is divided in half – 1 half completes the 2
conditions in 1 order & the other half completes it in reverse order. AB – BA.
Aims & hypotheses
Aim = general statement Hypothesis = a precise, testable
about the purpose of an statement about the expected
investigation outcome of the experiment
2 types of hypotheses
• Experimental hypothesis (alternative/research hypothesis)
States that there’s a relationship between the 2 variables being studied (1 variable
has an effect on the other). It states the results aren’t due to chance & they’re
significant in terms of supporting the theory being investigated. The IV will affect the
DV.
• Null hypothesis
States there’s no relationship between the 2 variables being studied (1 variable
doesn’t affect the other). It states results are due to chance & aren’t significant in
terms of supporting the idea being investigated. The IV will not affect the DV.
Non-directional hypothesis (two-tailed
Directional hypothesis (one-tailed hypothesis)
hypothesis) à simply predicts the IV will have an effect on
à predicts the nature of the effect of the DV but the direction of the effect isn’t
the IV on the DV – it only goes in one specified (don’t know what direction it’ll go in
direction (specific) but knows there’s a difference)
E.g., adults will correctly recall more E.g., there will be a difference in how many
words than children numbers are correctly recalled by children &
adults
Operationalising variables à many of the concepts used in hypothesis are abstract –
operationalising a hypothesis is saying specifically what you’re going to observe.
Operational variables refer to how you’ll define & measure a specific variable as it’s
used in your study.
E.g., Alcohol increases reaction time à ppts who drink 250ml of alcohol will have a
faster reaction time than ppts who drink 500ml
Variables & control
à an experiment is a study of cause & effect – involves deliberate manipulation of 1
factor/variable while trying to keep all other variables constant.
IV is variable known from the start of experiment – DV is one we find out
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