Experimental Design Flashcards
What is the independant variable?
the variable that is changed/controlled to test the dependent variable
What is the dependant variable?
the variable being measured
When might a within-participants design not be practical?
In an ageing study (because all participants are involved in both groups it would mean you would have to wait for them to age to conduct pt.2 of the study)
3 advantages of a within-participants design?
- manages individual differences
- inc statistical sensitivity
- less participants needed
3 disadvantages of within-participants design?
- participants are aware of hypothesis (hawthorn effect)
- need more stimuli
- might be susceptible to ‘order effects’
What are order effects?
differences that occur in research due to the order of the participants exposure to the materials etc.
Give 3 examples of order effects
- learning
- practice
- boredom/fatigue
Name and describe a solution to order effects
Counterbalancing - where research conditions are presented randomly in all permutations (all possible orders)
Explain mutual exclusivity
P(A+B)=0 - two things can’t occur at the same time (probability is 0)
Give examples of two types of mutually exclusive groups
Gender effects
Psych disorders
4 advantages of a between-participants design?
- participants don’t know the hypothesis or the other conditions; lowering demand characteristics
- no order effects
- less stimuli needed
- simple to design
2 disadvantages of a between-participants design?
- inc statistical noise (too much variation in results)
- more participants needed
Name 2 types of demand characteristics
- hawthorne effect
- placebo effect
What are demand characteristics?
participants form an interpretation of the experiment’s purpose and unconsciously change their behavior to fit that interpretation
Describe the Hawthorne Effect
the participant observes a change and wants to meet the demand of the experiment, so an effect happens regardless of the variable change
How can the hawthorne effect be prevented?
the participants being naive to the hypothesis
What are confounds?
uninteresting factors (e.g. social, environmental that weren’t being originally tested) that affect measurements systematically - can create bogus results
Give 4 examples of confounds
- time of testing
- gender of experimenter
- room noise level
- before/after a lecture
How can confounds be controlled?
By having a control experiment that is similar but not the same as the experiment. Having it double-blind improves also
What is a double-blind experiment?
Participants AND experimenter aren’t aware of group they are in/hypothesis etc
What can be a solution to deception in studies
Debriefing
What is the problem with informed consent?
It may introduce bias
What is the social desirability effect?
A response bias that causes respondents to answer in a way that they think will be viewed favourably by others. Causes people to over-report the good and under-report bad
