Quasi-experiments

Question 1

What is a Quasi-experiment

Answer 1

• studies that are ‘almost’ experiment
• a research method in which the experimenter has not manipulated the IV directly — the IV would vary whether or not the researcher was interested
• the researcher records the effects of the IV on a dependent variable and the DV may be measured in a lab

the experiment involves the manipulation of the IV and random allocations to the conditions by the researcher and it allows casual conclusions to be drawn

Question 2

What Types of quasi experiments are there?

Answer 2

-Natural experiments (those with an independent variable)
-Difference studies (those with no independent variable)

Question 3

Natural experiments

Answer 3

• conducted when it is not possible to deliberately manipulate an IV - said that the IV varies naturally and the DV may be tested in a lab
  For example:
• Effects of watching TV
  
  • before 1995 people living on st helena in the middle of the atlantic had no TV, the arrival of TV gave researchers a chance to see how exposure to western programmes may influence behaviour
• over charlton et al found no difference in either pro or anti social behaviour after this introduction (the IV was no TV and later exposure to TV

In these studies the IV was quite difficult to control by the researcher as it was bound to happen

Question 4

Difference studies

Answer 4

• IV is naturally occurring and DV can be measured in a lab
• key feature is that the IV has not been made to vary by anyone and is simply a difference between people that exists
  For example:
  
  • Gender differences
    Sheridan and king tested obedience by asking male participants to give genuine electric shocks of increasing advantage to a puppy
    
    • found that 54% of male participants delivered the maximum fatal shock but the 100% of women delivered a fatal shock

The IV in this study was gender which is a difference that cannot be manipulated so it is not a ‘true’ IV

Question 5

Evaluation of quasi experiments

Answer 5

There are several ways in which the researcher cannot establish a clear cause and effect conclusion from this which are:
- Manipulation of the IV
-lack of control of the IV means that it is more difficult to say that the change in the DV was caused by the IV
e.g if there were uncontrolled confounding variables then observed changes in the DV may not be due to the IV

Random allocation
- cannot randomly allocate participants like you do in independent groups which means that there may be biases within these different groups
- can cause uncontrolled confounding variables

Unique characteristics or participants
- the sample studied may have unique characteristics
e.g in the st helena study the people were apart of a pro-social community and were particularly helpful — this might explain why violence on TV did not affect their behaviour
- this means that the findings cannot be generalised to other groups of people so it essentially has low population validity