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Research MethodsNote: 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, repeated-measures

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 IV2. statement of DV3. statement of population (of interest)4. A prediction

Operationalised Independent & Dependent VariableOperationalising – 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.

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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

experiment

Identification of extraneous potential confounding variables variable Description Example AlternativesIndividual participant differences

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 results

Control group has 80% males, Experimental group has 80% females, gender may affect results

Use a repeated-measures design to eliminate individual participant differences or a matched-pairs design to reduce individual participant differences

Non standardised instructions & procedures

This involves subjects receiving different instructions, conducting experiment in a different context (different time of day, different location – could affect results)

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 effect

(see below)

Placebo effect

(see below)

Placebo Effect & the use of a PlaceboPlacebo effect



Explanation A tendency of participants expectations to influence their behaviour meaning that the IV is not the only variable influencing the value of the DV

And/or – the subjects knowing what group they are in (control or experimental) which can alter change their behaviour

What is a placebo

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

Use single blind procedure to overcome placebo effect

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.

Benefit of using a single blind procedure

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 effectExplanation 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 group)

2 types of Experimenter Effect1. 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 dataUse double blind procedure to overcome experiment effect

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.

Benefit of using a double blind procedure

So that the characteristics, influence or bias of the experimenter will not affect the results

In summary; Double blind (D.B) procedure controls both the placebo effect & experimenter effect, Single blind only controls



Order effectExplanation 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 effect

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

CounterbalancingUsed to eliminate order effect

Involves arranging the order in which the conditions of a repeated measures design are completed so that each condition occurs equally 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.

Repeated-measures design



Explanation 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)

Advantages 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)

Limitation But often leads to order effect (see above) which is eliminated by Counterbalancing

Independent-groups designExplanation 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

Advantage No order effect (as opposed to R.M)

Limitation 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)

Matched-Pairs designExplanation 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,

Advantage Controls the effects of the variable(s) on which participants are matched, thus Matched-Pairs minimises the differences between subjects in both the control and experimental groups.

So there is less chance of extraneous variables occurring than in Independent groups No order effects occur as opposed to repeated measures

Limitation The actual process of matching up subjects into pairs is a time consuming hence costly process

Not all critical factors are matched – i.e. There may be other factors that participants should be matched on, which may influence the

D.V If one subject withdraws from the experiment then the results of the other subject in the pair

are void.

Reporting conventions as per the APA (American Psychological Association) formatBasically 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 populationParticipant 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

Control Group vs. Experimental GroupControl Group Experimental Group

Exposed to IV No Yes



Purpose 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

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

Description Selecting readily available subjects without any attempt to make sample representative of the population of interestE.g. a Psych teacher using his/her class as subjects

Advantages Both time and cost effective

Limitations 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 SamplingDescription 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) sample

Advantages 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

Limitation 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 research

Sampling method: Stratified Sampling



Description Used when you have a diverse population i.e. different groups that you want represented

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 populationStep 3: Then select appropriate numbers of subjects from each strata.

Advantages Attempts to prevent biases by making the sample more representative of the population.

Limitations 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 SamplingDescription Used when you have a diverse population, i.e. different groups that you want

represented 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 populationStep 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.

Advantages Attempts to prevent biases by making the sample more representative of both the population & each strata involved

Limitations Time & associated costs of stratifying the population i.e. identifying & allocating people into ‘strata’ or subgroups – before selecting the random sample from each sample

Dot point # 3: Techniques of qualitative and quantitative data collection: case studies; observational studies; self-reports; questionnaires

Types of DataQuantitative data:



Explanation 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

Advantage Enables more precise analysis; i.e. data can be objectively measured, it can easily compared (using descriptive statistics) and analysed (using inferential statistics)

Consequently quantitative data can be summarised, analysed and interpreted more easily than qualitative data.

Qualitative data:Explanation 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,

Advantage Provides data that is richer in detail

Disadvantage 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 StudyExplanation 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

Advantage 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).

Limitations 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 injury) 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 generalisations

Data collection technique: Observational studies



Explanation 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

Advantage 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.

Limitations 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: Self-reportsExplanation 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.

Advantage 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.

Limitations 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: QuestionnairesExplanation Are a written set of standardised questions that can be taken anonymously



Advantage 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

Limitations 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: SurveysExplanation A group of participants are asked to respond to set of questions by either -

Face to face, mail, phone, etc.

Advantage It is a practical way of gathering information from a large number of participants

Limitations 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 answer

Data collection technique: InterviewsExplanation Can take the form of face-to-face/ phone forms of self-reports

Advantage 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

Limitations 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

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

Mean the average = the sum of all values/total number observed

Median shows the middle number/midpoint of each group - half the observations fall below & half above



Mode the most frequently occurring value in each group

p values & conclusionsInferring 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 Value

p stands for ProbabilityPsychologists 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 hypothesis

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



Conclusions 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.

Evaluation of research in terms of generalising the findings to the populationA Generalisation – 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 presentExamples 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)


Booze bus analogy: If the calculated p value is under 0.05 you are O.K the hypothesis is supportedBut if p value is over 0.05, then the possibility of chance factors influencing the result is over the limit, thus hypothesis is rejected

Make sure your conclusion contains the IV & DV.



















EthicsDot 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 researchSecondarily: 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

Beneficence The researcher has a responsibility to1. Maximise possible benefits2. Minimise potential risks or harm or discomfort to research participants

Integrity Demonstrated: by commitment by the researcher to the search for knowledge recognised principles of conducting research disclosure & communication of results

Justice Researcher must Avoid imposing an unfair burden of research on any individual or population of

interest 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 persons

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 rightsConfidentiality 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

study.

Voluntary participation

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



Informed consent procedures

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

Withdrawal rights

Participants are entitled to leave the study at any time during the conduct of the study.

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 in research

Deception is allowed when The ethics committee has given permission for deception in research to be used 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

Debriefing Subjects are debriefed at the conclusion of the experiment (not before or during) 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 formationNeurons 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 long-term 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.



Dendrites 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

Axons 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

Synapse 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 neuron.

Soma (contains nucleus)

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 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 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.

Synapse formation 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 synapse

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



The development of Neural Pathways

Learning results in the modification of neural connections by either1. 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 Pathways

The release of both glutamate & dopamine (both excitatory neurotransmitters) strengthen connections at the synapse during learning.

Specifically dopamine plays a role in reward-based learning and potential addictive behaviour. For example the first time we have a tim-tam 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.

Long-Term Potentiation

: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 brainPlasticity Refers to the brains ability to change throughout the lifespan as a result of

experience 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

stimuli. 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.Develop- Refers to changes in neural connections as a result of environmental



mental plasticity

interactions induced by learning that occur during development (childhood)

Thus developmental plasticity diminishes with age Thus the plasticity of the brain is a combination of genetic inheritance as

well as from experience.1. 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

2. Proliferation - unborn baby's cells (that are eventually going to become neurons) divide and multiply creating 250,000 cells p/min

3. Circuit formation - axons of the neurons branch out to target cells and form synapses with them

4. 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)

5. 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)

6. 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.Adaptive plasticity

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 adulthood.

Potentially brain functions can shift from damaged areas to undamaged 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 healthy)

Timing of experience

SENSITIVE PERIODS

vs.

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 3-7)

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.

CRITICAL PERIODS

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 dependent learning

vs.

Experience expectant learning

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 (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 PlasticityDevelopmental Plasticity Adaptive Plasticity

Definition 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.

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

Neuronal Changes

1. Proliferation2. Synaptogenesis3. Circuit formation4. Neural migration5. Myelination6. Synaptic pruning

1. Rerouting2. Sprouting

Occurs in response to

It is predetermined & occurs in response to the initial processing of sensory information by the immature brain

Compensation for brain injury and in adjustment to new experiences

When it occurs

It occurs over the lifespan, but diminishes with age

Also occurs over the lifespan, but is more efficient and effective during infancy/ early childhood.

Sensitive vs. Critical periods of learningSensitive periods Critical periods



Starts and ends Gradually abruptlyDuring the period

It is a period of maximal sensitivity

The organism has heightened sensitivity to external stimuli that are

compulsory for development of a particular skill

After the period The skill can still be learned, but less efficiently

The cortical areas allocated for the particular skill will adapt and perform a

different function.Examples Language development Development of binocular vision (from

@ 8 months to 3 years)

Experience expectant vs. experience dependent learningExperience expectant

learningExperience dependent learning

Stage of Lifespan that the genetic structural modifications occur

Early in life Over the lifespan in response to complex environmental stimuli

During which period

During the ‘Sensitive Periods’ There is no optimal period i.e. It occurs over the lifespan

Language Development of primary language (the brain expects to

be exposed to language)

Development of 2nd Language (it is dependent on exposure to

environmental stimuli) – the brain doesn’t expect us to become multi-

lingualGeneral or Specific

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

Unique to individuals e.g. Exposure to igloo building at a young age for

eskimos



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