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Research Methods
Note: These notes relate to both Units 3 & 4 Psychology
Dot point # 1: Experimental research
 Construction of research hypothesis
 Identification and operationalization of independent and dependent variables
 Identification of extraneous and potential confounding variables including individual
participant differences, non-standardised instructions and procedures, order effects,
experimenter effect, placebo effects
 Ways of minimising confounding and extraneous variables including type of sampling
procedures, type of experiment, counterbalancing, single and double blind procedures,
placebos, standardised instructions and procedures, evaluation of different types of
experimental design including independent-groups, matched-participants, repeatedmeasures
 Reporting conventions as per American Psychological Association (APA) format
Research Hypothesis put simply: is a statement of the predicted effect of a change in the Independent Variable
(IV) on the value of the Dependent Variable (DV)
It describes how the IV is manipulated & the procedures (operations) used to measure (& observe) the DV
A Research hypothesis must have
1. statement of IV
2. statement of DV
3. statement of population (of interest)
4. A prediction
Operationalised Independent & Dependent Variable
Operationalising – means specifying exactly how something is going to be measured and exactly how the
groups will be manipulated
Operationalised IV
A variable manipulated to test the effect on the DV
Operationalised DV
A variable which measures the effects of the manipulation of the IV
When asked to identify the Operationalised Independent Variable – look for 2 groups
E.g. participants who drink caffeinated drinks vs. decaffeinated drinks
When asked to identify the Operationalised Dependent Variable – look for the statistics – i.e.
Memory ability as operationalised as number of 30 three letter non sense syllables recalled.
Page # 1
People between the ages of 18 and 40 who sleep fewer than 6.5 hours per night for 12 months will have a larger
Body Mass Index than people who sleep more than 6.5 hours per night
DV: Increase in Body Mass Index
IV: Those who sleep fewer than 6.5 hrs or less vs. those who sleep more than 6.5 hours per night
Population: 18 – 40 Year olds
Prediction: Sleep deprived patients will have a higher BMI than non-sleep deprived subjects
Extraneous variables (EV) (the word extraneous means ‘outside’
So an EV is any variable outside the experimental design that may affect the D.V,
thereby having an unwanted effect on the results of the experiment and thus affecting the
ability of the researchers to draw conclusions.
So an EV is a variable other than the IV that may affect the DV
They can occur at any stage of an experiment – e.g. how the D.V was measured, how the
experimental group was treated (which may be different to treatment of control group)
EV’s occur randomly rather than systematically – i.e. they occur at a point of the
Identification of extraneous potential confounding variables
variable Description
The composition of the control
and experimental groups, may
contain significant difference
in terms of the intelligence,
past experience, memory
ability, gender mix, age spread,
etc – which may influence the
This involves subjects
standardised receiving different instructions,
conducting experiment in a
& procedures different context (different
time of day, different location
– could affect results)
Control group has
80% males,
group has 80%
females, gender
may affect results
Use a repeated-measures
design to eliminate
individual participant
differences or a matchedpairs design to reduce
individual participant
Comparing results
of Psych class A
(experiment done
Monday am, to
results of Psych
class B
(experiment done
Friday pm)
Use standardised
instructions and
procedures: i.e. same
experimenter, same
context, etc.
Order effect
(see below)
Experimenter (see below)
(see below)
Page # 2
Placebo Effect & the use of a Placebo
Placebo effect
What is a
Use single blind
procedure to
placebo effect
Benefit of
using a single
A tendency of participants expectations to influence their behaviour
meaning that the IV is not the only variable influencing the value of the
 And/or – the subjects knowing what group they are in (control or
experimental) which can alter change their behaviour
 A Placebo is a fake treatment often used in medical treatments e.g. a
sugar tablet given to the control group - the real tablet is given to the
experimental group.
 Neither group knows which one is receiving the placebo.
 The use/purpose of the placebo means that the difference in outcome
between control and experimental conditions will be due to the
independent variable & not the participants expectations
 Involves the experimenter allocating the subjects to the experimental
and control groups So they (the subjects) are blind to the knowledge of which group they
are in – i.e. experimental or control.
To avoid participants expectations/bias that may affect the results (a placebo
effect) as the participants are blind to whether they are in the control or
experimental group.
Experimenter effect
Use double
blind procedure
to overcome
Benefit of using
a double blind
Refers to the actions of the experimenter, rather than the I.V affecting
the value of the D.V, hence the results of the experiment.
 An experiment effect can occur when the unconscious (or inadvertent)
expectations, personal characteristics or treatment of the data (by the
experimenter) may bias the results (particularly for the experimental
2 types of Experimenter Effect
1. Self-fulfilling prophecy – which occurs when subjects behave the way
they think the experimenter, wants them to behave.
2. Experimenter Bias – unintentional actions that affect the collection/
treatment of data
 Allocates subjects to the experimental and control groups so that both
the experimenter and the subjects are blind to the knowledge of which
group they (the subjects) are in.
 By using an assistant to allocate the subjects to the control and
experimental groups.
 Thus the experimenter is blind to the knowledge of which group the
subjects are in.
So that the characteristics, influence or bias of the experimenter will not
affect the results
Page # 3
In summary; Double blind (D.B) procedure controls both the placebo effect & experimenter
effect, Single blind only controls
Order effect
where the order that a task was completed in a Repeated measures design
has a potentially confounding effect on the DV (hence results)
Types of order
1. Practice effect: performance on the task completed may be better
because of the experience gained in completing the 1st task (not
because of the IV)
2. Boredom effect: participants do worse the 2nd time around due to
boredom/ fatigue (if a long task)
3. History effect: the time interval between repeated testing (if long
term) may lead to changes in participants characteristics, potentially
confounding the effect of the treatment variable
Counterbalancing Involves arranging the order in which the conditions of a repeated
Used to eliminate measures design are completed so that each condition occurs equally
order effect
often in each position. I.e. get half the subjects to do the task under
experimental conditions first, and the other half performing the task
under control conditions 1st and then swapping around.
Confounding variables (the word confound means ‘confuse’)
 Are any variables other than the IV that has had an effect on the DV thus compromising the
results of the experiment.
 They occur when you have results that can’t be attributed to the I.V alone!
 They are systematic, that is they take effect right throughout the experiment
 The effects of the variable on the dependent variable are confused with that of the
independent variable.
 Gender can be a confounding variable because of the genetic & socialised difference
between males & females. E.g. alcohol may more effect on female reaction time, because
males (on average) have a higher body mass. So if a control group had proportionally more
females and the experimental group had proportionally more males, then gender could be a
confounding, because it is uncertain if the alcohol (CV) or the gender (IV) has affected
reaction time (the DV)
 E.g. using a repeated-measures design without counterbalancing, the order effect - could
confound the results
Many Extraneous Variables involve the personal characteristics of the subjects themselves. I.e. gender bias,
aged bias, intelligence levels, etc. These can be minimised by controlling the manner in which the subjects are
allocated to groups which is part of the experimental design
3 of these Experimental designs include
1. Repeated measures
2. Matched Pairs
3. Independent groups.
Page # 4
Repeated-measures design
Each participant is involved in both the Experimental & Control Condition, to test the
change in results (DV) from manipulation of a variable (IV) e.g. test subjects before
(baseline measure) and then again after (exposure to IV), then measure the change in
results (DV)
Eliminates (or controls) participant related variables, i.e. the
participants characteristics are the same across both conditions
The ability to use fewer participants (economise) than in ‘Independent groups’
Doesn’t require pre-testing as does ‘Matched Pairs’ (Saving time & cost)
But often leads to order effect (see above) which is eliminated by Counterbalancing
Independent-groups design
No order effect (as opposed to R.M)
subject variables can still occur and it is therefore the least effective of the 3 experimental designs
in minimising participant-related variables (particularly if a small sample was used)
allocates subjects to groups via a random procedure
each group is assigned to only 1 level of the independent variable/ they are assigned to the
experimental or control condition
Matched-Pairs design
Involves placing equivalent subjects into equivalent pairs and then selecting one from each
pair into the 2 groups (Experimental & Control)
Participants are matched according to the variable(s) whose influence should be controlled
e.g. intelligence, memory ability, etc.
The pairings could also be based on characteristics such as I.Q., age,
Controls the effects of the variable(s) on which participants are matched, thus MatchedPairs minimises the differences between subjects in both the control and experimental
So there is less chance of extraneous variables occurring than in Independent groups
No order effects occur as opposed to repeated measures
The actual process of matching up subjects into pairs is a time consuming hence costly
Not all critical factors are matched – i.e.
There may be other factors that participants should be matched on, which may influence the
If one subject withdraws from the experiment then the results of the other subject in the pair
are void.
Page # 5
Reporting conventions as per the APA (American Psychological Association) format
Basically a research report should describe –
 What was done
 Why it was done
 How it was done
 What was found
 What the findings mean
And it should contain the following sections
 Title
 Abstract (100-150 words) – with aim, method, results, conclusion
 Intro – background, past results, aim, hypothesis
 Method: participants, materials & procedure
 Results
 Discussion – conclusion, statement of significance , identifying ext/ confounding
variables & suggestions to overcome, degree to which findings can be generalised to
broader pop
 References & Appendices
Dot point # 2: Sampling procedures in selection and allocation of participants
 Sampling procedures in selection and allocation of participants: random sampling,
stratified sampling, random-stratified sampling, convenience sampling
 Random allocation of participants to groups: control and experimental groups
Participant selection & allocation
Sampling procedures
A Population- is the body of the community from which a sample of participants is drawn
So if there is a random sample of 30 VCE students from Pentridge S.C, then the
population is VCE students at Pentridge S.C
 Selecting subjects for research is called Sampling
 A Sample is a subset of a larger group i.e. the Population to be studied.
 The sample should be representative of the population
Participant Allocation – once participants have been chosen to be in a sample, they then need
to be allocated to different groups (control & experimental)
Random allocation- each participant has an equal chance of being allocated to the control or
experimental group
 This ensures that each group (Experiment & Control) are as similar as possible in terms
of personal characteristics of interest
Page # 6
Control Group vs. Experimental Group
Exposed to IV
Control Group
The control group acts as a baseline
comparison that helps determine
whether the I.V has affected the D.V,
i.e. caused a change in behaviour
Experimental Group
to observe the effects of the IV on
the subjects behaviour
4 methods of sampling include – Convenience Sampling Random Sampling & Stratified sampling Stratified
Random Sampling
Sampling method:
Convenience Sampling aka Opportunity sampling
Selecting readily available subjects without any attempt to make sample representative
of the population of interest
E.g. a Psych teacher using his/her class as subjects
Both time and cost effective
Because sample is not representative of the population, it makes it difficult (unlikely)
that accurate inferences can be made about data obtained, which makes it unlikely that
generalisations can be made to the wider public.
Sampling method:
Random Sampling
Allocates subjects from the population to form part of the sample, so that every
member of the population of interest has an = chance of being selected (i.e. there is
no bias in participant selection)
A sample that doesn’t give everyone (in the population to be studied) an = chance of
being selected is a biased Sample. i.e. it is an unrepresentative (of the population)
If a sample is large enough, then the participant variables will be distributed in the
sample in roughly the same proportions as in the population (so these participant
variables will not affect the DV)
Thus it improves the chances of making accurate inferences about the population
based on results gained from the sample
Not appropriate for all types of research – e.g. If doing research on schizophrenia,
these people (the population of schizophrenics) may be difficult to obtain for
Page # 7
Sampling method:
Stratified Sampling
Used when you have a diverse population i.e. different groups that you want
Divides the population of interest into different strata i.e. groups and then selecting a
sample from each stratum in the same proportions as the population.
Strata’s might be based on age, gender, living areas, marital status (or a combination
of factors)
3 steps
Step 1: place the name of each person from your population into the appropriate category
(e.g. gender - due to a gender bias in the population)
Step 2: Decide on the size of the population to be used and then calculate the number of
subjects required from each strata to form the same proportions found in the population
Step 3: Then select appropriate numbers of subjects from each strata.
Attempts to prevent biases by making the sample more representative of the population.
Time & associated costs of stratifying the population i.e. identifying &
allocating people into ‘strata’ or subgroups – before selecting the
sample from each sample
Participants from each strata may not be a good representation of that
strata, hence potentially biasing results.
Sampling method:
Random-Stratified Sampling
Used when you have a diverse population, i.e. different groups that you want
Divides the population of interest into different strata i.e. groups and then selecting
a random sample from each stratum in the same proportions as the population.
Strata’s might be based on age, gender, living areas, marital status,
3 steps
E.g. if stratified sampling of Sacre Coeur students was conducted i.e. yr.0 – yr.12 – the
ratio of yr 12 students to yr.2 students would be approx 4:1, since there are 20 yr.2
students and 80 yr.12 students.
Step 1: place the name of each person from your population into the appropriate
category (in this case year level)
Step 2: Decide on the size of the sample to be used and then calculate the number of
subjects required from each strata to form the same proportions found in the population
Step 3: select participants at random using a random number generator (or similar
method) so that each person in the population has an = chance of being selected as the
others in the stratum.
Attempts to prevent biases by making the sample more representative of both the
population & each strata involved
Time & associated costs of stratifying the population i.e. identifying & allocating people
into ‘strata’ or subgroups – before selecting the random sample from each sample
Page # 8
Dot point # 3: Techniques of qualitative and quantitative data collection: case studies;
observational studies; self-reports; questionnaires
Types of Data
Quantitative data:
Is based on numbers or mathematical expressions (e.g. mean, correlation coefficients, etc.)
Information is based on quantities.
This data is collected through systematic and controlled processes
Can be statistically analysed – e.g. Psych students at S.C have an average IQ
of 112, whereas the average IQ for S.C students in other VCE subjects is 106
Enables more precise analysis; i.e. data can be objectively measured, it can
easily compared (using descriptive statistics) and analysed (using inferential
Consequently quantitative data can be summarised, analysed and interpreted
more easily than qualitative data.
Qualitative data:
Based on written statements, which describes changes in the quality of behaviour (based on
personal accounts relating to feelings, attitudes, etc.)
i.e. information is based on qualities,
Provides data that is richer in detail
This data is difficult to statistically analyse, because it is often subjective e.g.
political opinions, opinions on single sex vs. co-ed schools, etc.
Thus interpretation of results is more susceptible to experimenter effects
Data collection technique:
Case Study
 is an in depth study of an individual or group (uses a combination of observation, interviews,
diagnostic tests) used to study rare disorders
 E.g. Phineas Gage
 Case studies provide ideas for further (experimental) research
 Provides a detailed & (near) complete description of 1 person’s situation and experiences & an
evaluation of treatment including background, family history, environment through 1 on 1 interviews,
individual testing, etc.
 Thus a hypothesis or theory can be proposed
 They provide ideas for theoretical explanations (& experimental research).
Page # 9
 Lack of control over variables meaning a cause and effect relationship cannot be established.
 Difficult to analyse a huge collection of data, i.e. time consuming to analyse, summarise & report
the data
 Difficult to generalise data to other people for instance many case studies involve unique
situations, if look at neural case studies, we need to remember that there are large differences
between brains, the plasticity of the brain (how each brain recovers differently from an identical
 Brain injuries are rarely localised to anatomical boundaries, hence it’s difficult to be certain as to
area of the brain responsible for specific behaviour or mental problems, making it difficult to make
Data collection technique:
Observational studies
Observing & recording behaviour in a natural setting (not in a lab) and then attempting to
generate conclusions based on observations.
E.g. naturalistic observation; observing subjects/ animals in an inconspicuous manner (possibly
without informed consent) e.g. for instance observing animals in the wild (chimps)
E.g. participant observation: e.g. researchers being admitted to a psychiatric hospital for mental
illness to record the treatment of patients
 Good starting point for most scientific research
 Allows us to study behaviour that has not been tampered with by outside influences i.e. in
their natural environments, so behaviour is not affect by artificial surroundings. Thus enabling
researchers to gain more accurate information.
 Often it is impractical to study behaviour in a laboratory setting e.g. gauging the
psychological effects of a miscarriage.
It describes behaviour, but not the cause.
Risk of Observer effect, which occurs when the presence of researchers effects the
organism’s behaviour e.g. if researching ‘birth order’ behaviour in children, the subjects (the
children) may act differently if aware of adults observing their behaviour
Observer bias: occurs when the observers expectations, motives, past experience affects the
accuracy of their observations e.g. They ignore certain behaviour or treat certain subjects
differently (i.e. from the control group)
Ethical issues – in terms of violation of privacy, there is a lack of informed consent
Data collection technique:
Written/oral responses to questions/statements
Thus enabling individuals to provide a subjective account of their attitudes/ feelings, etc.
E.g. Questionnaires, surveys & interviews
These can take the form of Open ended questions - requiring participants to describe their thoughts, feelings e.g.
Describe your attitude to gambling
Ratings e.g. Likert scale e.g. rate your night’s sleep from 1: Very poor to 7: Excellent
Closed Questions: Should students be drug tested on campus: Yes, No, Not sure
Fixed responses: e.g. when your child is naughty do you A: smack them B: Send them to
time out, etc........... These style of questions enable more objective and quantitative data to
be collected, described, interpreted & analysed.
Can provide some highly descriptive data (if open ended questions are used)
Sensitive data can be gathered due to anonymous nature of subject’s responses.
Page # 10
 Some subjects may have difficulty expressing their thoughts
 Some subjects may not give honest answers due to self-perceived pressures to conform to
social norms, thus affecting the accuracy and validity of such data
 It is difficult to convert responses to quantitative data, thus making it difficult to statistically
analyse & consequently interpret data. Hence analysis becomes subjective (there is a risk of
experimenter effect).
Data collection technique:
Are a written set of standardised questions that can be taken anonymously
 The anonymous nature of self-reports encourages subjects to be more candid (honest) in the
nature of their responses.
 Relatively easy in the modern era to direct to subjects e.g. online, email, mail, etc., hence a
relatively cheap means of data collection
 Subjects may misinterpret questions, thus affecting accuracy/ validity of data
 Lengthy Questionnaires can lead to boredom, thus affecting accuracy of data and ability of
the researcher to generate conclusions.
Data collection technique:
A group of participants are asked to respond to set of questions by either Face to face, mail, phone, etc.
It is a practical way of gathering information from a large number of participants
 It is difficult, time consuming & costly to obtain a representative sample i.e. a small group that
accurately reflects the larger population, hence we need to be careful generalising results to the
larger population if we are unable to obtain a representative sample
 Wording effect: occurs when the phrasing or order of questions, affects how participants
Data collection technique:
Can take the form of face-to-face/ phone forms of self-reports
If using an unstructured interview, the interviewer has the flexibility to ask follow-up questions to
responses in order to add to the richness of data collected
Data can be difficult to summarise, analyse & describe
Dot point # 4: Statistics
 Measures of central tendency including mean, median and mode
 Interpretation of p-values and conclusions
 Evaluation of research in terms of generalising the findings to the population
Page # 11
Descriptive Statistics
Describe, organise & summarise important characteristics of data and make it more clearly understood
Allows experimenter to make comparisons
E.g. working out the mean I.Q for the class and comparing that to SAC/ Exam result to see if there is a
link between Intelligence Quotient and academic results.
What conclusions can be made from descriptive stats???? - - - - - None!!!!!
Measures of central tendency
Are used to summarise a set of observations in a data set
the average = the sum of all values/total number observed
shows the middle number/midpoint of each group - half the observations fall below & half above
the most frequently occurring value in each group
p values & conclusions
Inferring from data
After the experiment has been conducted – researchers need to work out if differences between the results of the
control group & the experimental group are due to the I.V or Chance.
Inferential statistics – determine the probability that the difference in results is due to chance
Statistical Significance – The Probability is represented as the p
p stands for Probability
Psychologists generally accept a p value of 0.05 or less written as p <0.05
Calculating the p value is based on the differences in the means of the 2 groups (Control & Experimental) as
well as sample size. It is a VCE Psychology mandate that students are not required to make statistical
calculations – you just need to know how to interpret the p value.
A level of significance of 0.05 means that there is a 5% probability that the results are due to chance
alone (i.e. not due to the manipulation of the IV)
Or another way of putting it, is there is a 95 % chance or more that the correct conclusion was made & that the
results aren’t due to chance
Statistically significant
Occurs when the p value obtained is less than or equal to 0.05 (which is the confidence interval used in
VCE Psychology)
If an experiment finds no significant difference – then the interpretation is that observed differences
between groups could be due to chance.
Be careful, because even if we obtain p < 0.001, supporting our hypothesis, we still can’t establish cause &
effect – or proof – so we don’t say that the hypothesis is correct or true we just say the results support the
Page # 12
Why do experimenters do tests of significance? – 1. To be sure that the I.V is responsible for results & 2.
That results aren’t due to chance.
So if the p value is < 0.05, e.g. the calculated p value = 0.04 your conclusion is
the results are statistically significant & there is a 4% probability that the difference between the
results of the 2 conditions was due to chance alone
Alternatively, you could state - that there was a 96% probability that the difference between the
results of the 2 conditions was due to the IV & not due to chance.
No significant difference – indicates that the observed differences are due to chance
Booze bus analogy: If the calculated p value is under 0.05 you are O.K
the hypothesis is supported
But if p value is over 0.05, then the possibility of chance factors
influencing the result is over the limit, thus hypothesis is rejected
A Conclusion – is a final decision about what the results obtained from an investigation mean.
i.e. whether the hypothesis is supported or rejected based on the p value obtained.
E.g. the faster the tempo of the music listened to by the participants driving on an open road, the greater the
speed limit was exceeded. .
You can conclude a treatment has worked if the results for the experimental are significant (p < 0.05).
The conclusion only relates to the sample group tested, so it’s O.K to make a conclusion even if there are
extraneous variables.
Make sure your conclusion contains the IV & DV.
Evaluation of research in terms of generalising the findings to the
– is a judgment about the extent to which the research findings can be applied
to the population (from which the sample was drawn)
 Note: generalising the results to the sample cannot be done; rather generalising the results to the
population can be done
 Generalisations can be risky – if confounding or extraneous variables were present
Examples of reasons why results of an experiment might not be generalised
Non random selection of participants
Participants volunteered, hence were not representative of the population (since not everyone in population
had an equal chance of being selected)
Gender of participants was NOT controlled i.e. one group was mainly females, the other was mainly males,
thus creating a gender bias.
There might be order effects due to use of repeated measures design – e.g. (for IQ tests – people can
improve results on certain tests)
Sample size is too small compared to the actual population
Participant expectancy (placebo) effects might have contributed to the outcome (a single blind procedure
was not used)
Page # 13
Dot point # 5: Ethical principles and professional conduct
 Role of the experimenter
 Protection and security of the participants rights, confidentiality, voluntary participation,
withdrawal rights, informed consent procedures, use of deception in research
Protection and security of participants rights – via the Code of Ethics
The code of ethics provides guidelines to researchers that must be followed when working
with people or animals in research situations.
Primarily: Protect the welfare & rights of human participants in research
Secondarily: Promote research that will benefit the community or humankind (maximise beneficence)
Thus research must ensure
 subjects suffer no physiological or psychological harm
 there is no invasion of privacy which can cause stress
 that subjects aren’t coerced into participation which can cause duress
 To achieve this, 4 basic principles are described: integrity, respect for persons, beneficence, and justice
The researcher has a responsibility to
1. Maximise possible benefits
2. Minimise potential risks or harm or discomfort to research participants
Demonstrated: by commitment by the researcher to the
 search for knowledge
 recognised principles of conducting research
 disclosure & communication of results
Researcher must
 Avoid imposing an unfair burden of research on any individual or population of
 Design research so that selection, in/exclusion, recruitment of research participants
is fair
 Not discriminate in the selection/recruitment of subjects on the basis of race, age,
sex, religion, etc. – except where the inclusion/exclusion of groups is essential for
the research
Respect for
Demonstrated when the research regards the welfare, rights, perceptions of all
individuals involved in research
i.e. ensuring that consent documents are formatted in a manner that makes it easy
for participants to understand the nature of the experiments, potential risks, etc.
prior to their acceptance to participate.
Participant’s rights
Confidentiality 
The participants must not be identified in terms of their test results,
involvement in the study or any other confidential data.
This should be described to the subjects at the beginning of the
Consent of participants must be on a voluntary basis i.e. they must not be placed
under pressure to take part or be ‘conned’/coerced into participating
Page # 14
Participants must be given adequate information about
 nature of the study – what the results will be used for
 details of the processes involved in the study.
 the rights of the participants – re withdrawal, confidentiality, debriefing,
dangers etc.
the potential risks involved for the participants
Participants are entitled to leave the study at any time during the conduct of the
Participants may withdraw their results from the study at any time following
the completion of the study.
This should be explained to them prior to the commencement of
the study.
Use of deception Deception is allowed when
 The ethics committee has given permission for deception in research to be
in research
the value of the research is such that the deception is warranted.
Appropriate debriefing procedures are in place to ensure that no
lasting psychological or physiological harm to participants occurs
Subjects are debriefed at the conclusion of the experiment (not before or
Done to prevent psychological/ physiological harm to participants
Providing the participants with information about the nature & reason for any
deception that was used
Corrects mistaken attitudes & beliefs about the research
Used to minimise (or extinguish) any negative consequences that
participants might have suffered
The neural basis of Memory formation
Neurons are the core components of the nervous system, a neuron is an electrically excitable cell that processes
and transmits information by electrical and chemical signaling.
The neuron in
memory formation
Neurons are capable of a change in their function – which enables longterm storage of newly learned information occurs via 2 interdependent
processes (not independent)
The role of
Neurotransmitters in
memory formation
1. An increase in the amount of neurotransmitters produced (& released)
by the presynaptic neuron
2. Greater effects of neurotransmitter at its receptor sites of the post
synaptic neuron (thus the receptors are more sensitive to incoming
messages in the form of the neurotransmitters from the axon terminals
of the presynaptic neuron.
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Dendrites function like antennae, they are the branched projections of a neuron that
received input (electrochemical stimulation) and communicate with other neural cells
to the cell body, or Soma.
In relation to memory formation: Dendrites become bushier – (more
spines) thus enabling more synapses or more synaptic connections
(more storage space in effect)
When memories are retrieved, the functional & structural changes are
further strengthened
Acts as a conduit, An axon is a long, slender projection of a nerve cell, or
neuron that conducts electrical impulses away from the neuron's cell body
or soma.
Myelin Sheath
The axon is protected & insulated by the myelin sheath, the myelin sheath
facilitates the transmission of neural impulses
The Synapse is a junction that permits a neuron to pass an electrical or chemical signal to
another cell via the terminal buttons at the end of axons to the dendrites of the next
Soma (contains
The Soma is the cell body (the cell factory), which contains the nucleus which contains
most of the cell's genetic material, it is the control center of the cell
Neurotransmitters are the chemicals which allow the transmission of signals from one
neuron to the next across synapses. Neurons connect to each other to form networks.
Neural basis of learning
Neurotransmitters are the chemicals which allow the transmission of signals from one
neuron to the next across synapses. Neurons connect to each other to form networks.
Occurs when there is a creation of a new neural formation
Thus learning results in relatively permanent changes in the synapses of
animals neurons.
Learning & the
Learning can result in new synapses being formed – or –
The connections between neurons at the synapse can be strengthened
thus making it more likely that these neurons will fire again together
and transmit signals in the future.
Thus regularly revisiting a learned skill or memory such as your ability
to speak a second language – will strengthen the neural connections
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The development Learning results in the modification of neural connections by either
of Neural
1. Establishment of new neuronal pathways, which strengthens the
learning process – or 2. Existing pathways between neurons can be reorganised i.e. a ‘rewiring
of the brain’ thus making neuronal communication easier next time.
 According to Hebb (1949) when in a neurotransmitter is repeatedly sent
across a synaptic gap, the connection between the pre & postsynaptic
gap is strengthened (they fire at the same time)
 But if the memory is not revisited they stop firing at the same time and
the connections are weakened are and less likely to fire in the future
(neurons that fire together are wired together)
 LTP is critical for learning via the repeated stimulation of the
connection and the increased responsiveness of the postsynaptic neuron
to the presynaptic neuron.
The development 
of Neural
The release of both glutamate & dopamine (both excitatory
neurotransmitters) strengthen connections at the synapse during
Specifically dopamine plays a role in reward-based learning and
potential addictive behaviour. For example the first time we have a timtam it turns out to be a pleasurable experience increasing the release of
dopamine which in turn motivates us to repeat this behaviour –
particularly when given the cue of a plate full of tim tams on a table for
guests at a friend’s house.
:LTP refers to the strengthening of synaptic connections between the
presynaptic neuron & the postsynaptic neuron
Thus the pre and postsynaptic neurons communicate more easily, so in
effect the postsynaptic neuron becomes more responsive to the
presynaptic neuron through repeated stimulation – which in turn
strengthens the memory circuit, making the memory easier to retrieve.
In essence LTP thus making learning possible for animals.
Plasticity of the brain
Refers to the brains ability to change throughout the lifespan as a result of
Put simply: The brains ability to change with learning.
There is a change in the internal structure of neurons, notably the synaptic
connections as well as
An increase in the number of synapses in response to environmental
E.g. in relation to memory formation - new areas continued to develop in
adulthood such as the hippocampus.
This process continues from the embryonic stage and continues into old
age as we continue to learn.
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Refers to changes in neural connections as a result of environmental
interactions induced by learning that occur during development
Thus developmental plasticity diminishes with age
Thus the plasticity of the brain is a combination of genetic inheritance as
well as from experience.
Synaptogenesis – refers to an explosion of synaptic formation that occurs
during early brain development to enable the brain to deal with the
bombardment of sensory input
Proliferation - unborn baby's cells (that are eventually going to become
neurons) divide and multiply creating 250,000 cells p/min
Circuit formation - axons of the neurons branch out to target cells and
form synapses with them
Neural Migration occurs from 8 weeks to 29 weeks (i.e. movement of
neurons to different parts of the brain – based on their specialised function
e.g. visual neurons to the occipital lobe)
Myelination starts during foetal development through to adolescence (a
process of protecting & insulating neurons to aid the transmission of
impulses from 1 nerve cell to the next)
Synaptic pruning – refers to a neurological regulatory process in which
the overall number connections are reduced to enable more efficient
synaptic configurations which enables more efficient brain functioning
(hence ongoing learning).
This synaptic pruning takes place in different brain areas at different stages
of development, depending on when these brain areas are no longer used.
Thus we actually have significantly less synaptic connections in adulthood
than when in early childhood (@ 3 y.old – when the number of synaptic
connections peaks)
NOTE: Developmental plasticity diminishes with age.
Refers to the brains ability to reorganise neural pathways in response to
new experiences as well as enabling the brain to compensate for lost
functionality due to brain damage.
Adaptive plasticity explains why pianist has more significant cortical areas
in their motor cortex as their brain has been ‘adapted’ in response to the
stimulation of developing their craft.
E.g. the London cab driver whose brain has adapted (by growing) by
developing more grey matter in their hippocampus (due to their superior
expertise in the form of spatial navigation/ memory in comparison to bus
drivers who drive the same route every day)
So adaptive plasticity enables brains to adapt (by growing) for individuals
with the acquisition of expertise in a certain area e.g. Students, bilinguals,
musicians, etc.
It occurs across the lifespan, but Usually quicker during childhood than adulthood or old age in particular,
thus if we suffer from a brain injury we will recover better and potentially
gain greater functionality if the injury occurs during childhood rather than
Potentially brain functions can shift from damaged areas to undamaged
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Timing of
areas e.g. damage to areas of the motor cortex, can result in the individual
regaining movement by a shift in motor areas (in some cases the opposite
cerebral hemisphere).
1. Rerouting of neurons can occur – in which a new connection is made with
an active neuron
2. Sprouting – involves the growth of dendrite fibres thus enabling the
neuron to make new connections with other neurons.
 NOTE: Adaptive plasticity is maintained as we age (providing we remain
 The brain of a developing individual is more plastic than that of an adult
 During development there are specific times when a biological event is
more ‘sensitive’ to environmental stimuli e.g. language acquisition (age 37)
 Exposure to the environmental experience results in a rewiring of the brain
(i.e. the establishment of a neural pathway resulting in learning) – which
will optimally occur during the SENSITIVE PERIOD of learning
 We can still learn after the sensitive period has closed, but the learning
process is less efficient.
 E.g. the brain is sensitive to exposure to language (from the ages of 3 to 7)
in order for the language systems in the brain to develop.
 Refers to a finite period in which learning in response to either new
‘experiences’ or as a result of the change in structure or function of
developing neural circuits.
 E.g. certain areas of the auditory cortex and visual cortex are only capable
of synapse formation during early stages of development; once the crucial
period has elapsed the individual will have some auditory or visual
impairment in terms of processing particular sounds or vision.
 E.g. Hubel & Wiesal temporarily blindfolded a kitten during a critical
period (of visual development) from birth to 3 months when the blindfold
was taken off, it never fully developed vision in the blindfolded eye. It
actually resulted in reduced dendritic branching at the end of the neuron in
comparison to the non-deprived eye which had increased afferent activity
as the eye developed.
 Experience expectant learning – describes genetically structural
modifications that occurs early in life.
 The brain ‘expects’ and is primed for being exposed to the environmental
‘experience’ resulting in a rewiring of the brain (i.e. the establishment of a
neural pathway resulting in learning. E.g. the brain expects to be exposed
to visual images, sounds, etc. in order for our visual, auditory, etc. systems
to develop.
 Experience dependent learning - refers to additional skills developed over
the lifespan (that the brain doesn’t expect e.g. an eskimo child learning
how to build an eskimo – which is dependent on observational learning.
Thus structural modifications to the brain occur over the lifespan as result
of exposure to complex environmental stimuli.
 Experience expectant learning occurs during ‘sensitive periods’ – as
opposed to experience dependent learning which occurs over the lifespan
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(i.e. there is no optimal time)
Learning a first language is Experience EXPECTANT (the brain expects
to be exposed to 1 language)
Learning a second language is Experience DEPENDENT Experience (the
brain doesn’t expect to be exposed to multiple languages), thus developing
bilingual capabilities is dependent on exposure to another language (other
than the primary language)
Experience dependent learning is unique to individuals; experience
expectant occurs to nearly all members of a species.
There is no optimal period for experience dependent learning e.g. you can
learn how drive when your 16, 30 or 50 (older people may struggle due to
age related memory decline e.g. slowing of the Central.N.S)
E.g. the brain expects to be exposed to visual images, sounds, etc. –
shortly after birth in order for our visual, auditory, etc. systems to develop.
Developmental vs. Adaptive Plasticity
Developmental Plasticity
Occurs in
response to
When it
Changes in neural connections as a
result of interactions with the
environment (our experiences
during childhood) as a consequence
of developmental processes.
e.g. development of visual cortex.
1. Proliferation
2. Synaptogenesis
3. Circuit formation
4. Neural migration
5. Myelination
6. Synaptic pruning
It is predetermined & occurs in
response to the initial processing of
sensory information by the
immature brain
It occurs over the lifespan, but
diminishes with age
Adaptive Plasticity
The brains ability to compensate for
lost functionality due to brain damage
as well as in response to interaction
with the environment by reorganising
its structure
1. Rerouting
2. Sprouting
Compensation for brain injury and in
adjustment to new experiences
Also occurs over the lifespan, but is
more efficient and effective during
infancy/ early childhood.
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Sensitive vs. Critical periods of learning
Sensitive periods
Critical periods
Starts and ends
During the
It is a period of maximal
After the period
The skill can still be learned,
but less efficiently
The organism has heightened
sensitivity to external stimuli that are
compulsory for development of a
particular skill
The cortical areas allocated for the
particular skill will adapt and perform a
different function.
Development of binocular vision (from
@ 8 months to 3 years)
Language development
Experience expectant vs. experience dependent learning
Experience expectant
Early in life
Experience dependent learning
During which
During the ‘Sensitive Periods’
There is no optimal period i.e. It occurs
over the lifespan
Development of primary
language (the brain expects to
be exposed to language)
General or
General – e.g. We are all exposed to
visual stimuli, thus the brain expects
and is highly responsive to visual
stimuli during the sensitive periods
Development of 2 Language (it is
dependent on exposure to
environmental stimuli) – the brain
doesn’t expect us to become multilingual
Unique to individuals e.g. Exposure to
igloo building at a young age for
Stage of Lifespan
that the genetic
modifications occur
Over the lifespan in response to
complex environmental stimuli
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