Participant/Experimental Design Flashcards
Participant/Experimental Design
A01- Repeated Measures
Repeated Measures= All participants take part in ALL CONDITIONS of the study, experiencing BOTH manipulations of the independent variable
Eg 10 ppts complete the word based memory test without eating chocolate, the same 10 ppts also completed the word based memory test after eating chocolate
Participant/Experimental Design
A03- Repeated Measures
Strength
There is no issue with individual differences as all participants complete all the conditions, meaning there is no participant variable which could influence the results. This means a cause and effect relationship can be established increasing the validity of the experiment
Participant/Experimental Design
A03- Repeated Measures
Weakness
The validity of a repeated measures experiment may be compromised through order effects, the results may be skewed by participant gaining practise, or undergoing fatigue as they complete all conditions, suggesting the condition they complete second will gather less accurate results.
Participant/Experimental Design
A01- Repeated Measures; counterbalancing
Counterbalancing
A way of reducing order effects in repeated measure designs is counterbalancing. Where participants are split into two sub groups group 1 completes condition A then condition B, then group 2 completes condition B hen condition A. Therefore any impact of order effects occurs in both condition and therefore improving the validity.
Participant/Experimental Design
A03- Repeated Measures
Weakness
The validity of repeated measure design experiments can also be limited through the potential for demand characteristics. As all participants complete all conditions, there is a risk they could guess the aim of the study and so alter their behaviour in response. Therefore not presenting a genuine objective behaviour which can be analysed and reducing the accuracy of the study
Participant/Experimental Design
A01- Independent measures
Independent measures= Participants being split into groups and completing one condition each
Eg 10 ppts complete the memory test with chocolate and a separate 10 ppts complete the memory test without chocolate
Participant/Experimental Design
A03- Independent measures
Strength
The data is likely to be valid as there is little chance of demand characteristics. Participants only complete one condition of the study, and so are unlikely to guess the aims of the study and change their behaviour. This is also true for order effects and therefore the behaviour is likely to be genuine and so accurate.
Participant/Experimental Design
A03- Independent measures
Weakness
However, validity can be compromised through extraneous variables such as participant variables which may cause problems with the accuracy of the conclusions. As different groups complete each condition there is likely to be individual differences in each group with can make it hard to establish a strong cause and effect conclusion
Participant/Experimental Design
A03- Independent measures
Weakness
In terms of cost benefit, independent measures may not be justifiable in terms of the validity issues as it is more expensive to perform than repeated measures to gather the same amount of data. Therefore, it may be preferable to use a repeated measures design and reduce validity issues through counter balancing to keep the cost low
Participant/Experimental Design
A01- Matched Pairs Design
Matched pairs= Similar to independent measures in that there are different groups of ppts completing each condition. However the participants are careful allocated as they are pre- matched on factors such as age, gender and intelligence(depending on relevance)
Participant/Experimental Design
A03- Matched Pairs Design
Strength
The effect of participants variables is reduced as it ensures the participants in each groups are similar, allowing a cause and effect relationship to be established and so improving validity.
(However the C + E relationship is not as strong as it is in repeated measures)
Participant/Experimental Design
A03- Matched Pairs Design
Weakness
In terms of cost benefit the cost may outweigh the benefits for certain studies as pre- assessment is needed to match the participants across groups. This can give rise to practical issues as it may be time consuming and costly, meaning another experimental design would have to be considered.
