Research Methods: Experimental Designs - Independent Groups, Repeated Measures, Matched Pairs - KR Flashcards
What is meant by an independent groups design?
participants only take part in one condition
Which experimental design has different participants in each condition?
independent groups design
How is an independent groups design conducted?
Split your group of participants into equal sized groups then allocate one group to each condition
What is meant by order effects?
When participants complete more than one condition and may become bored/ tired in the second condition or better at the second task. therefore affecting the internal validity
What is a strength of participants completing only 1 condition
no order effects
What is the key term for participants becoming bored/ tired or better in the second condition?
Order effects
Why are there no order effects in independent groups design?
Participants only take part in one condition so will not get bored/tired or better in the second condition.
Aside from order effects what is an alternative strength to using independent groups design?
Can be used when repeated measures is inappropriate
Why can independent groups be used when repeated measures is inappropriate?
when conducting a quasi experiment i.e. gender differences
What type of validity improves when order effects are avoided?
internal validity
Why does the internal validity of a study increase when order effects are eliminated?
Because the results aren’t being affected so we are measuring what we said we would.
What is meant by individual difference?
Characteristics of participants that may affect the results
What is a weakness of using an independent groups design?
individual differences
Which experimental designs are affected by individual differences?
independent groups and matched pairs
Which experimental design is affected by order effects?
repeated measures
Why is independent groups design negatively affected by individual differences?
There are separate groups of ppts so ppts may have characteristics in one condition tht affect the DV
Give an example of an individual difference that would affect a memory study
better/ worse memory
Why are individual differences an issue when using an independent groups design
it lowers the internal validity of research
What is meant by repeated measures design?
participants take part in all conditions
Which experimental design do participants take part in all conditions?
repeated measures design
How is a repeated measures design conducted?
Participants complete one condition, then after a time lapse (1hr) they complete the second condition.
What needs to be done to the DV in a repeated measures design to make sure we have internal validity?
the task (DV) should be different but matched on the same difficulty or measuring the same thing as the previous task.
What are the two strengths of using a repeated measures design?
individual differences are removed and requires fewer participant
Why are individual differences removed in a repeated measures design?
the same participants take part in all conditions
Individual differences and repeated measures: As participants take part in all the conditions, what can researchers be sure of?
the researcher can be sure that any changes to the DV are of the result of the IV
Why does repeated measures require fewer participants?
All participants take part in all conditions.
Why is it a strength of repeated measures that it requires fewer participants?
Less time and money is spent in sampling and allocation of participants.
Why will order effects be present in a repeated measures design?
participants complete all conditions so therefore may perform worse in the second condition due to boredom or due to practice
In order effects, which condition is going to be affected by boredom or practice?
the second condition
Aside from order effects, what is another weakness of using a repeated measures design?
Demand characteristics
What is a demand characteristics?
When participants change there behaviour to help or hinder the researcher
Why would participants be able to change your behaviour to help or hinder the researcher
Participants are able to pick up on clues given off by the study of the aim of the research
Why are demand characteristics an issue in a repeated measures design?
it lowers the internal validity of research
Why does demand characteristics lower the internal validity of research?
We are no longer measuring the effect of the IV on the DV but the changed behaviour
What is a matched pairs design?
Participants are matched on important characteristics in a study
What experimental design do researchers pre-test participants?
Matched pairs
How are participants allocated once they have been paired from the pre test
randomly allocated
How is a matched pairs design conducted?
choose a variable, pre test, match, randomly allocate
What are the two strengths of matched pairs design
reduces individual differences and no order effects
Why does matched pairs have no order effects?
participants are randomly allocated to ONE condition
Why is a matched pairs design time consuming?
Researchers have to pretest before allocation of conditions
Why is the fact that a matched pairs design is time consuming a weakness?
the researcher would need a large pool of people to select and because the process is lengthy more time and money is spent before the test has begun.
What experimental design is being used and justify your answer?
independent groups, participants only complete one condition (10 ppts have to learn a list of words in the same room and 10 ppts have to learn a list of words in a different room)
What experimental design is this and justify your answer?
independent groups, participants only complete one condition (drinking red bull vs not drinking red bull)
What experimental design is this and justify your answer?
independent groups, participants only complete one condition (learning a list of words with or without pictures)
What experimental design is this and justify your answer?
independent groups, participants only complete one condition (with or without music)
What experimental design is this and justify your answer?
independent groups, participants only complete one condition (waiters who gave eye contact vs waiters who gave no eye contact)
What experimental design is this and justify your answer?
Repeated measures, participants take part in all conditions (rating of interaction before and after language therapy)
What experimental design is this and justify your answer?
repeated measures, participants take part in all conditions (watching a horror film and watching a romance film)
What has been done to this study to control the effects of repeated measures
counter balancing
What is meant by counterbalancing?
changing the sequences of conditions for some participants
What is meant by ABBA?
one half of the participants complete condition A then B, the other half complete condition B then A
How is counterbalancing conducted?
one half of the participants complete condition A then B, the other half complete condition B then A
Why is counterbalancing used?
to reduce order effects?
Why does counterbalancing reduce order effects but doesn’t remove order effects?
because participants are still completing all conditions so order effects is spread amongst the conditions
What experimental design has been used and justify your answer?
repeated measures, participants take part in all conditions (before and after the prison conditions changed)
What experimental design has been used and justify your answer?
Repeated measures, participants take part in all conditions (before and after aversion therapy)
