Types of experiment

What are laboratory experiments?

Conducted in highly controlled environments

What are the strengths of lab experiments?

• High control over CV and EVs → high internal validity

• Replicability

What are the limitations of lab experiments?

• May lack generalisability due to artificial setting + unusual behaviour from participants in an unfamiliar context → low external validity.

• Demand characteristics are more likely to occur

• Low mundane realism

What is a field experiment?

The IV is manipulated in a natural, everyday setting → researcher goes to participant’s usual environment, not a lab

What are the strengths of field experiments?

• High mundane realism because of natural environment

• High external validity - behaviour more authentic

• No demand characteristics - participants are generally unaware they are being studied

What are the limitations of field experiments?

• Not replicable due to loss of control over CV and EVs.

• Ethical issues: participants who are unaware they are being studied cannot consent, may be invasion of privacy

What is a natural experiment?

Researcher has no control over the IV - can occur in a lab

What are the strengths of a natural experiment?

• Provides opportunities for research that may not otherwise be undertaken for practical or ethical reasons.

• High external validity as real-world issues are studied as they happen

What are the limitations of natural experiments?

• Naturally occurring events happen rarely

• Not generalisable

• Not clear whether the IV is affecting the DV as there is no random allocation

• Research taking place in a lab is subject to lacking realism and demand characteristics

What are quasi-experiments?

The IV is an existing difference between people that has not been manipulated, it simply exists

What are the strengths of quasi-experiments?

Replicable - carried under controlled conditions

What are the limitations of quasi-experiments?

• Confounding variables - participants cannot be randomly allocated

• The researcher cannot claim the IV has made any observable change as they are not manipulating it.

What are ‘true’ experiments?

The researcher is in direct control of the IV and records the effect of the DV. Only lab and field experiments are true experiments