Types of Experiment

Lab Experiment

Highly controlled environment.

Strengths:
1. high control over CVs and EVs → high internal validity
2. replication = easy

Limitation:
1. low external validity → not real life, behaviour can’t be generalised to real life setting
2. Unnatural behaviour (demand characteristics) due to unfamiliar environment & knowledge of study
3. Low mundane realism → task set isn’t applicable to life

Natural experiment

IV occurs naturally in the environment (e.g. natural disaster)
Researcher can’t control IV or what has an effect on it
DV may be naturally occurring (e.g. exam results) or may be devised like in field/lab

Strengths:
1. opportunities for somewhat otherwise unethical/impractical research
2. High external validity - real life circumstances

Limitations:
1. Rare → limits generalisation
2. Not randomly allocated to experimental conditions → researcher unsure of causal relationship between IV & DV
3. Research conducted in lab → lack realism & demand characteristics prevalent

Field experiment

IV = manipulated in natural environment
Researcher goes to participants’ familiar environment

Strengths:
1. High mundane realism
2. Valid & authentic behaviour → high external validity
3. Participants unaware of study → ext valid

Limitations:
1. Loss of control of EV & CV
2. difficult to establish cause-and-effect
3. ethical issues → lack of consent → invasion of privacy

Quasi experiment

Naturally occuring IV based on difference between people (e.g. gender)
Not able to manipulate IV
DV may also be naturally occurring or not

Strengths:
1. controlled conditions →share some strengths of lab (replication)

Limitations:
1. no random allocation → confounding variables
2. IV not delib changed → cant claim it caused observed changes