Practise identifying participant, situational and uncontrolled variables, explaining their effect and standardising the procedure to protect internal validity.
Dr Bakar is investigating the effect of boredom on people's estimation of time. Her participants were separated into two groups and did different activities:
- Group A watched an exciting film (non-boring activity)
- Group B moved small boxes from one pile to another (boring activity).
Both activities lasted 30 minutes. Each participant was asked to estimate how long the activity had lasted.
Dr Bakar is concerned about possible differences between individuals in Group A and Group B that could affect the validity of her study.
Suggest why two possible differences between individuals in Group A and Group B could lower validity.
difference 1
difference 2
Suggestion of difference in participant variables =1[×2]
Why =1[×2]
- Watch more films / more interested in films; (suggestion)
- Likely to get involved (so time passes faster); (justification)
- Do box moving type job / shelf stacker; (suggestion)
- Even more bored so time moves extra slowly; (justification)
- Better at timing; (suggestion)
- Better timing when bored / in box condition; (justification)
- It may be that one person really likes moving boxes/stacking shelves more than another (suggestion)
- So they really get involved in the task (so time passes more quickly)