experimental designs

• what is independent measures?

  involves using different people in each condition

  each participant is allocated a different condition
• * less affected by demand characteristics for i.m?

  • in a r.m p are more likely to guess aim of study as they are taking part in both conditions
  • this is less likely to occur in i.m
  • results will be more accurate as they are not impacted from unnatural behaviour from someone guessing the aim & changing their behaviour
• * less affected by order effects for i.m?

  • in a r.m participants results may be affected by order effects
  • p could get better in task through practice/performance in second task/could get worse through fatigue
  • in i.m p only complete one condition so that this does not happen
  • p will not be negatively impacted from doing more than 1 condition & can establish cause & effect relationship
• X individual differences for i.m?

  • participants in each group are different so performance could be affected by personality/intelligence rather than iv
  • cannot establish cause & effect relationship as there may be other factors affecting dv other than the iv
• what is experimental design?

  how to allocate condition to participants
• what is repeated measures?

  involves using the same people in each condition
• * less affected by individual differences for r.m?

  • same participant takes part in both conditions so only change between the conditions is the iv
  • the results are going to be accurate since we can minimise evs & results will not be negatively impacted by factors such as age/gender
• X demand characteristics for r.m?

  • as p is taking part in both conditions it is likely they could guess aim of study
  • p may behave unnaturally after guessing the aim so results will be unrealistic
• X order effects for r.m?

  • p taking part in two conditions could be vulnerable to order effects
  • means they may get better in the second condition through practice/could perform worse as they are tired/bored
  • results will be negatively impacted & researcher cannot establish cause & effect relationship
• what is matched pairs?

  involves using different participants in each condition but participants are matched by doing a pretest
• explain 4 stages of matched pairs?

  1. pretest (variable has to be relevant)
  2. match then split
  3. each pair goes into each condition
• * less affected by individual differences for m.p?

  • differences are minimised at the start by matching participants such as same age
  • results are more accurate as there are no evs affecting dv
  • results are not going to be negatively impacted & can establish cause & effect relationship​
• * reduced order effects for m.p?

  • are only doing one condition so will not get bored & will not be able to guess the aim so will be no changes to behaviour
  • will be more realistic since they only do condition once so no one can guess the aim
  • results will be more accurate
• X of impossible to match pairs exactly?

  • e.g hard to find someone with the same iq,age, gender as one of these may be lacking so it is difficult to conduct
  • confounding variables can still affect dv so cannot determine that the iv is only thing affecting dv
• time consuming X for m.p?

  • participants need to be matched to another person with similar qualities can be time consuming for researcher as they will have to conduct pre tests
  • the intial match making tests conducted before the study is less time efficient
• what is counterbalancing?

  when the participants are divided into 2 groups & do the conditions in different order

  minimises order effects
• * quicker to carry out for i.m?

  • p only do one condition so both conditions can be done at same time & same day
  • researcher cn do variety of different conditions at one time & have wider set of results
  • results will be more accurate as researcher has more time to gather range of results as all conditions can be done at one time as different p used for different groups