Psychology - Experimental Designs

Question 1

Experiment Designs

Answer 1

This refers to how participants are allocated to the different groups in an experiment. Types of design include repeated measures, independent groups and matched pair designs.
Probably the most common way to design an experiment in psychology is to divide the participants into 2 groups , the experimental group and the control group . Then introduce a change to the experimental group .
The researcher must decide how they will allocate the sample to the different experimental groups .

Question 2

Independent Measures / Independent Groups

Answer 2

Independent measures design , also known as between-groups is an experimental design where different participants are used in each condition of the independent variable . This means that each condition of the experiment includes a different group of participants .
This should be done by random allocation , which allows every participant a chance to be assigned to a group .
After the participants have been recruited they should be randomly assigned to a group , this can ensure that the groups are similar reducing participant variables.
Independent measures involve using two separate groups of participants , one in each condition .

Question 3

Pros and Cons of independent Groups

Answer 3

Pros - Avoids order effects as people participate in one condition only

Cons - More people are needed and is more time consuming .
Differences in the individuals may affect group performance

Question 4

Repeated Measures

Answer 4

Repeated Measures design is an experiment design where the same participants take part in each condition of the independent variable .
Repeated Measures is also known as Within groups or Within-Subjects Design

Question 5

Pros and Cons of Repeated Measures

Answer 5

Pros - As the same participants are used in each condition , participant condition is greatly reduced.
Fewer people are needed and this also saves time .

Cons - Order effects may occur ( order effect is the order a certain condition(s) will effect a participant ) .

Question 6

Counter Balancing

Answer 6

To combat order effects the researcher shall counter balance the order of all the conditions for the participant

Question 7

Pros and Cons of Counter Balancing

Answer 7

Reduces participant variables because the researcher has tried to pair up individuals with similar abilities for each condition .

Cons - If one participant drops out you will lose 2 participants data .
Very time consuming and almost impossible to match people so that every ability is similar .

Question 8

Experimental Design Summary

Answer 8

Experimental design refers to how participants are allocated to the different conditions in an experiment .

There are three ways in which this is done ;

Independent Measures / Between-Groups - Different participants are used in each condition of the independent variable .

Repeated Measures / Within-Groups - The same participants take part in all conditions of the independent variable .

Matched Pairs - Each condition uses a different set of participants but they are still matched in important characteristics such as gender , age , etc