Chapter 6: Methodological Control in Experimental Research Flashcards
What is a between-subjects design?
participants are in group A or B
what is a within-subjects design?
participants are in groups A and B
What are the disadvantages of between-subjects designs?
- Large numbers of people may need to be recruited, tested, and debriefed
- Differences between conditions might be due to the independent variables or differences between individuals
Wha are the advantages of between-subjects designs?
Participants are naive to the research hypothesis
When and why do we make equivalent groups?
in between-subjects designs because differences between conditions might be due to the independent variables or due to differences between the individuals
How can we create equivalent groups?
Via random assignment or matching techniques
what is blocked random assignment?
ensures each condition has an equal amount of randomly assigned participants
What is matching?
participants are grouped together based on a subject variable (matching variable) and are then randomly distributed to conditions. Good for small participant numbers.
we must be confident that the matching and dependent variables are correlated and it must be possible to assess participants on the matching variable
What are the advantages of within-subject designs?
Fewer people need to be recruited
and it eliminates the equivalent groups problem
What are the disadvantages of within-subject designs?
Order effects: type of sequencing effect that is a consequence of the order in which participants are administered the experimental conditions
What are progressive effects?
performance changes progressively from trial to trial
what are carryover effects?
some sequences produce different effects from others
What is counterbalancing used for?
it controls order effects by using more than one sequence
what counterbalancing techniques can you use if a participant is tested once for each condition?
complete or partial counterbalancing
What is the difference between complete and partial (incomplete) counterbalancing?
in complete counterbalancing every possible sequence is used at least once
in partial counterbalancing a subset of the total number of orders is used
How can one control order effects?
with counterbalancing
what counterbalancing techniques can you use if a participant is tested more than once for each condition?
reverse counterbalancing and block randomisation
what is reverse counterbalancing?
the conditions are presented in a certain order and then again in the reverse order
what is block randomisation?
every condition must occur once before any are repeated & the order of conditions is randomised within each block
what is a benefit of block randomisation over reverse counterbalancing?
it prevents participants from knowing what condition is coming next
What are the 3 study designs used in developmental research?
cross-sectional, longitudinal, and cohort sequential designs
what is the benefit of longitudinal designs over cross-sectional designs?
there are no cohort effects
what is a benefit of cross-sectional over longitudinal designs?
they take less time
What is experimenter bias?
when a researcher’s cognitive bias causes them to subconsciously influence the participants of an experiment
How can you control for experimenter biases?
mechanise procedures, use protocols, or use a single-blind or double-blind procedure
What is the difference between a single-blind and double-blind design?
in a double blind design neither the participant nor the experimenter know which condition the participant is in
what is subject bias / the Hawthorne effect?
when knowledge about an experimental condition influences a participant’s responses or behaviour
What are some influences on subject bias?
demand characteristics, evaluation apprehension, the participant’s temperament
What are some ways to reduce subject bias?
- reduce demand characteristics
- use placebo control group
- perform manipulation check
- conduct field research
