part 1: deciding on a research question, reliability & validity

independent variable (IV)

the variable the psychologist manipulates to see how it effects behaviour

dependent variable (DV)

the variable which is measured by the psychologist

experiment

• a research method where cause and effect is measured through the control and manipulation of key variables

• participants are randomly allocated to control groups

hypothesis

a precise and testable statement about the assumed relationship between the variable

standardised procedures

the experiment should be replicable

• so anyone else can repeat it to see if the results are reliable

• participants do the same thing in each condition

operationalisation of variables and eg

• giving a precise definition of the behaviour being observed/ measured

• allows for repetition and raises reliability as it’s an agreed value that has been attributed to the measurement

• e.g how fast someone can run - need measurement (seconds, minutes, hours)

aim of the research

broad statement of the purpose of the research

confounding variables

• variables that are not being measured or manipulated

• affects some participants behaviour not not others

• has a negative effect on validity

C - circumstances - some circumstances

extraneous variables

• variables that are not being measured or manipulated

• affect the results of all participants

A - ALL

examples of confounding variables

• fatigue

• stress levels

• participants prior knowledge

examples of extraneous variables

• noise level

• lighting

• temperature

extraneous and confounding variables can then be split into…

situational variables

participant variables

situautional variables and an example

• any factor in the environment that could affect the DV

• noise, time of day

participant variables and examples

• characteristics of individuals that may influence outcome of study

• age, intelligence

what are pilot studies

a small-scale trial run of a research design before doing the real thing

• to find out if the design works and see what needs adjusting

• results of a pilot study are irrelevant

flaws that could occur in a pilot study

• participants don’t understand the questions

• participants get bored if there’s too many tasks or questions

• particulars may guess what an experiment is about

what are confederates

• a person that plays a role in the experiment

• e.g dressed in a suit to ask questions

directional hypothesis and an example

• the IV will affect the DV in one specific direction

• used when past rewatch suggests findings will go in a specific direction

• e.g alcohol slows reaction time

non-directional hypothesis and example

• the IV will affect the DV but does not state a specific direction

• used when there is no past research

• e.g alcohol affects reaction time

null hypothesis and example

• suggests there will be no difference between variables

• alcohol will have no effect on reaction time

alternative hypothesis

• alternative for a null hypothesis

• statement of effect - general term for directional/ non-directional hypothesis

how to write a hypothesis to get a fully operationalised hypothesis

• possible hypothesis

• state the levels of the IV (needs to have atleast 2 conditions to make a comparison)

→ e.g short bursts , longer sessions

• operationalise the variables

• fully operationalised hypothesis

what are co -variables

• two or more quantities being measured in a correlation by the researcher that may or may not vary with each other

reliability is associated with… and an example

• consistency

• e.g if you measure a chair two days in a row with a ruler you will get the same results - the ruler is reliable

what is inter-rater reliability

• where two or more psychologists produce consistent results using a standardised procedure, agreed coding system or correlation of their data

what is the general rule if data has inter-observer reliability

• if there is more than an 80% agreement on observations

how to deal with reliability

• have measures which improve consistency and accuracy within the results

• e.g standardised procedures

how to improve reliability in observations

• observers should be trained in the use of coding system / behaviour checklist

what is internal reliability

• the extent to which a test or measure is consistent within itself

• e.g the use of standardised procedures and instructions, all the questions on an IQ test measuring the same thing

what is external reliability

• the extent to which a test produces consistent results over several occasions

• e.g an interview 2 weeks in a row with the same people producing the same results

how to assess internal reliability and what to do if there’s low-internal reliability

• split half method

• involves a participants test answers being spilt in half and seeing whether they got similar scores on both half’s

• low internal reliability - remove questions to see if test returns to high

how to assess external reliability

• test-retest method

• giving a participant a test, questionnaire or interview and then giving them it again some time later - answers should be the same

• low external reliability - rewrite questions - they may be poorly written causing confusion, retrain interviewer to be more consistent

how can the scores be compared in the split-half method and test-retest method

• by calculating a correlation coefficient

what is validity

• how accurately a measure explains behaviour - whether it measures what it claims to

what is the effects of extraneous/ confounding variables

can cause:

• random errors - unpredictable, affect all conditions equally

• constant errors - vary between conditions and impact some conditions more that others

→ e.g a slow computer in one condition is constant but only effects one condition

how to control extraneous and confounding variables

• standardise procedures - all participants have the same experience

• randomly allocate participants to groups

• single or double-blind designs

• large sample size to account for individual differences

what is internal validity

• factors within the study - the finding are accurate and the effects on the DV are caused by the IV

what is external validity

• whether the study paints a true picture of real life behaviours

• e.g having mundane realism

• whether the findings would apply to different places, time or people - can be generalised

what can affect internal validity

• lack of mundane realism - lack of realistic conditions lead to unnatural behaviour

• extraneous/confounding variables - can impact internal validity

how can situational variables affect validity and be overcome

• affect validity - act as an extraneous variable e.g poor lighting affecting performance on a memory test

• overcome - standardised procedures - tested under same conditions

how can participant variables affect validity and be overcome

• affect validity - differences between participant causes changes in the DV

• overcome - repeated measures design, matches pairs design

two types of internal validity

• concurrent - comparing a measurement with an established measurement that has known validity - similar results → valid

→ current - current & established tests

• construct - whether the overall results reflect the phenomena (thing) as a whole - most sophisticated test of validity

three main types of external validity

• ecological validity - how well the study’s setting reflects real-world situations

• population validity - how well the study’s findings apply to different groups of people

• temporal validity - whether the study’s findings remain relevant over time

what are demand characteristics and what can they negatively do

• cues that cause participants to unconsciously work out the aim and act differently

• type of confounding variable - threaten internal validity

what are the two types of demand characteristics?

• everyday demand characteristics - different situations creating different expectations

e.g music alone - listen, concert - jumping,shouting

• experimental demand characteristics - participants are unsure what to do - looks for clues (demand characteristics) - figure out hypothesis - behave differently

examples of experimental demand characteristics

• title of study

• rumours about study

• researchers interactions

• study setting

what is researcher bias

• the researcher directly or indirectly influences the results of the study

• can be a confounding or extraneous variable

indirect investigator effects that contribute to researcher bias

investigator experimental design effect - operationalise variables so the desired effect is more likely

investigator loose procedure effect - don’t clearly specify the standardised instructions - leaves room for results to be influenced by experimenter

how to deal with specific validity issues (researcher bias, social desirability bias, demand characteristics)

• single blind design - participant is not aware of research aim

• double blind design - both the participant and experimenter are not aware of the aim

• experimental realism - making the task sufficiently engaging - participant pays attention to the study not that ther being observed

what is social desirability

• when participants give the response they think will show them in the best possible light - not a true reflection

how do we assess validity

• face validity

• content validity

• concurrent validity

• construct validity

• predictive validity

what is face validity

• whether the test appears to measure what it claims to

• least sophisticated measure of validity

what is predictive validity

• the degree to which a test accurately forecasts a future outcome on a more broadly related topic

• e.g higher IQ - higher grades in exams

what is content validity

• checking if the test covers all aspects of the topic it’s meant to measure

how can you improve internal validity

• revise questionnaire so it better matches to construct

how can you improve external validity

• change sampling method - to better reflect population

what is the target population (sampling)

• the group of individuals that a researcher is interested in studying

• e.g people in the uk

what are sampling frames

• smaller, identifiable group within the target population

• used when it’s unrealistic to study the whole target population

• e.g people in London

what is a sample

• the actual participants chosen from the sampling frame - ideally representing the target population

what is random sampling a + and -

• every member of the target population has an equal chance of being selected e.g drawing mass from a hat

• pro - fair - reduces researcher bias

• con - potentially unrepresentative - subgroups may still be over or underrepresented

what is self-selected/ volunteer sampling and a + and -

• individuals volunteer to participate after responding to an advert

• pro - attract participants who are genuinely interested - motivated

• con - they may not get enough volunteers

what is snowball sampling and a + and -

• initial participants recruit further participants

• pro - helps researches access hard-to-reach populations

• con - sample may be biased- share similar traits

what is opportunity sampling and a + and -

• the researcher selects participants who are willing to participate

• pro - quick and convenient

• con - may produce an unrepresentative sample as its people available - limits generalisability

what is systematic sampling and a + and -

• every nth person from a sampling frame is selected e.g every 3rd person in a register

• pro - simple and structured - reduces researcher bias

• con - may still produce an unrepresentative sample - certain participants skipped

what is stratified sampling and a + and -

• the target group is divided into sub groups e.g age, gender and a proportionate number from each group is selected randomly

• pro - representative sample

• con - time-consuming

what is quota sampling and a + and -

• target population is divided into subgroups and the participants are chosen from each group at the convenience of the researcher

• pro - guarantees representation of all key subgroups - proportion to its size

• con - time consuming

what are the two types of observational sampling

• event sampling

• time sampling

what do observational sampling techniques do

• collect data about specific data or events within specific time frames

what is event sampling and + and -

• observing participants and recording a specific behaviour every time it occurs (like a tally chart)

• pro - straightforward to conduct, records every instance of behaviour to provide a complete record

• con - doesn’t show when behaviour occurred, overwhelm researcher - miss them ?

what is time sampling and + and -

• where the psychologist records behaviour at specific time intervals e.g every 15 minutes and creates an average score e.g pulse rate

• pro - shows how behaviour changes over time - see patterns, reduces researcher overload - more likely to be accurate

• con - may miss behaviour between intervals, complex to organise

key features of a lab experiment (3)

• controlled, artificial setting to ensure only the IV is being manipulated and nothing else is altering the DV

• standardised procedures so every participant gets the same experimental experience

• variables are controlled so there’s no extraneous variables

• experimenter will manipulate the IV and measure DV → two or more conditions

name + and - of laboratory experiments

pros:

• standardised procedures - replicated by other researchers - high reliability if results are consistent

• extraneous variable are controlled -reasonably certain the change made to the IV was what caused to change in the DV

cons:

• low ecological validity - artificial conditions

• may be demand characteristics - artificial environment so participants may guess the aim

Key features of a field experiment (3)

• takes place in a natural environment e.g school, street, hospital

• researcher manipulates at least one IV and measures at least one DV

• Lower control over confounding variables but can still have a standardised procedure

Name + and - of field experiments (3)

+higher mundane realism as the environment if less artificial - higher ecological validity

+reduced demand characteristics - aim is less apparent - reduced chance of participant effect and more valid behaviour

-ethical issues- if they are unaware of study, cannot provide valid consent, deceived? - psychological harm

-harder to control extraneous and confounding variables - not got complete control over the environment - reduce internal validity as we cannot be certain that it was the IV that changed the DV

Key features of conducting research online (3)

• Participants are accessed via the internet/ social media etc

• often involves questionnaires

Name + and - of conducting research online

+large samples - potentially millions of people

+sample can be more diverse as it accesses a wider range of people - more generalisable and representative of population

-no way of controlling extraneous or confounding variables - participants taking the questionnaire unobserved

-may still end up with a biased sample even though it’s larger - older people less likely to be online, unrepresentative