RM - Natural and quasi experiments Flashcards
Why aren’t quasi and natural experiments true experiments?
Because the IV is not deliberately manipulated meaning that it is not possible to claim that changes in the DV are caused by the IV.
What is a natural experiment?
A research method in which the experimenter has not manipulated The IV directly for ethical or practical reasons. The IV would vary whether or not the researcher was interested. The researcher records the effect of the IV on the DV - this DV may be measured in a lab.
What are quasi-experiments?
Studies that are almost experiments. The IV is actually not something that varies at all - it is a condition that exists. The researcher records the effect of this ‘quasi-IV’ on a DV.
When is a natural experiment conducted?
When it is not possible, for ethical or practical reasons, to deliberately manipulate the IV.
What are limitations of natural/quasi-experiments?
No manipulation of the IV - the lack of control over the IV means that we cannot say for certain that any change in the DV was caused by the IV. This means that any conclusions about cause and effect can only be tentative.
Random allocation is not possible meaning that participant variables may differ between the 2 groups. The lack of random allocation in natural and quasi-experiments means that there may be uncontrolled confounding variables.
The unique characteristics of the sample mean that the findings can’t be generalised to other groups of people (i.e the studies may be described as having low population validity.
Can only be used in conditions vary naturally.
The DV may be a fairly artificial task, reducing mundane realism.
When are the four different experiments used?
LAB - to investigate causal relationships between an IV and DV under controlled conditions.
FIELD - to investigate causal relationships between an IV and DV in less controlled, more natural surroundings.
NATURAL - to investigate relationships between an IV and DV in situations where IV cannot be directly manipulated for ethical or practical reasons.
QUASI - to investigate relationships between an IV and DV in situations where IV is a characteristic of the person (e.g. age or gender or level of depression).
What are strengths of natural experiments?
Allows research where IV can’t be manipulated for ethical or practical reasons.
Enables psychologists to study ‘real’ problems such as the effects of a disaster on health (increased mundane realism and ecological validity).
What are strengths of quasi-experiments?
Allows comparisons between types of people.
What is controlled and what is natural in a laboratory experiment?
Both IV and Dv are controlled.
What is controlled and what is natural in a field experiment?
IV is controlled and DV is natural.
What is controlled and what is natural in a Quasi-experiment?
Natural IV and controlled DV.
What is controlled and what is natural in a natural experiment?
Both IV and DV are natural.
Rank the 4 types of experiments from most valid to least valid:
Most - Natural - Quasi - Field - Laboratory Least
Rank the 4 types of experiments from most realistic to least realistic:
Most - Laboratory - Field - Quasi - Natural Least
