Experimental Designs Flashcards
Name the 3 experimental designs.
Independent measures
Repeated measures
Matched pairs
What is an experimental design?
The different ways in which PPTs can be organised in relation to the experimental conditions.
What are independent measures?
Where different groups PPTs experience different conditions of an experiment to each other.
What are the issues with PPT variables in independent measures?
What variable does this act as, and what issue does this lead to?
PPTs in the different conditions are different to each other. This acts as a confounding variable, leading to validity issues.
How do researchers deal with PPT variables in independent measures?
They randomly allocate PPTs to their groups.
What are the economical issues with independent measures?
Each PPT will only contribute to a single result. Therefore, more time and money must be spent recruiting more PPTs.
Why are there no issues with order effects in independent measures?
PPTs do not have to repeat the experiment again, leading to less risk of demand characteristics.
What are repeated measures designs?
All PPTs experience both experimental conditions (levels of the IV) in a study.
How do repeated measures designs lead to order effects?
PPTs have to experience similar experimental conditions more than once. This could lead to fatigue/boredom, so PPTs do not try as hard on the second task. Or, it could lead to PPTs improving at the task due to practice, giving the impression that the second task is easier.
How do researchers using repeated measures deal with order effects?
Explain what this technique is.
They use counterbalancing.
This is where PPTs are randomly divided into groups. Some PPTs may experience experimental condition A first, then B, while others may experience experimental condition B first, then A.
How do repeated measures lead to demand characteristics?
PPTs will be more likely to figure out the aims of the experiment after experiencing different levels of the IV. This means there are more risks of please U and screw U effects.
What are the benefits of controlling PPT variables in repeated measures?
This leads to higher…
Individual PPT differences will not influence findings for each of the experimental conditions, leading to higher validity.
Why are repeated measures designs more economical?
Fewer PPTs need to be recruited, saving time and money.
What are matched pairs designs?
PPTs are paired together bases on a specific variable relevant to the experiment. Eg; IQ in a memory test.
Matched pairs designs allow what variables to be controlled?
Participant variables, a confounding variable.
