Research Methods - Types of experiment Flashcards
What are the 4 types of experiments?
- Laboratory experiment
- Field experiment
- Natural experiment
- Quasi-experiment
What are the 3 key characteristics of a laboratory experiment?
A controlled environment where extraneous and confounding variables can be regulated.
Participants go to the researcher.
The IV is manipulated and the effect of the DV is recorded.
What are the 3 key characteristics of a field experiment?
The setting is natural.
The researcher goes to the participants.
The IV is manipulated and the effect of the DV is recorded.
What are the 2 key characteristics of a natural experiment?
The experimenter does not manipulate the IV - someone/thing else causes the IV to vary…it varies naturally.
The DV may be naturally occuring or may be devised by the experimenter and measured in the field or a lab.
What are the 2 key characteristics of a quasi-experiment?
Iv is based on a pre-existing difference between people e.g. age or gender. No one has manipulated this variable, it simply exists.
DV may be naturally occuring or may be devised by the experimenter and measured in the field or a lab.
Evaluate the strengths and weaknesses of a laboratory experiment.
Strengths:
EVs and CVs can be controlled so their effect on the DV are minimised and the cause and effect between the IV and DV can be demonstrated…high internal validity.
Cna be more easily replicated so findings can be confirmed and validity is further supported.
Limitations:
May lack generalisability as lab is artificial and participants are aware they are being studied so behaviour may not be natural or everyday…low external validity.
Demand characteristics may be an issue due to the cues in the experimental situation so findings may be a result of these cues not the effect of the IV…low internal validity.
Evaluate the strengths and weaknesses of a field experiment.
Strengths:
More natural experiment so behaviour of participants is more authentic and results may be more generalisable.
Participants are unaware they are being studied so behaviour of participants is more authentic and results may be more generalisable and has greater external validity.
Limitations:
More difficult to control EVs and CVs so it is difficult to establish cause and effect.
Ethical issues as participants in the field may not have given informed consent and is therefore and invasion of privacy.
Evaluate the strengths and weaknesses of a natural experiment.
Strengths:
May be the only practical and ethical option as it may be unethical to manipulate the IV e.g. when studying the effects of institutionalisation on children.
Has great external validity as they involved real world issues such as effects of a natural disaster on stress levels so findings are more relevant to real experiences.
Limitations:
The natural event may only occur rarely (one-offs) so reduces opportunity for research and may limit the scope of generalising findings to real experiences.
Participants are not randomly selected as the IV is pre-existing so may result in CVs that aren’t controlled e.g. Romanian orphans adopted early may also be the more friendly or well-behaved ones.
Evaluate the strengths and weaknesses of a natural experiment.
Strengths:
There is often high control so replication is possible.
Comparisons can be made between people as the IV is a difference between people.
Limitations:
Participants are not randomly allocated to each condition as the IV is pre-existing so may result in participant variables causing the change in the DV.
Causal relationships aren’t demonstrated as the IV is not manipulated or controlled by the researcher so we cannot say for certain if the change in the DV is due to the IV.
