Types of Experiments

What is a lab experiment?

They are experiments conducted in highly controlled environments.

What happens to the IV in a lab experiment?

Manipulated by researcher

What is a strength of doing a lab experiment?

- more control over variables

- high internal validity

What are some weaknesses of doing a lab experiment?

- ethical issues if consent isn't given

- lacks external validity

- demand characteristics

What is a field experiment?

An experiment that takes place in a natural, public setting

What happens to the IV in a field experiment?

Manipulated by researcher

What are some strengths of a field experiment?

- high mundane realism

- high ecological validity

- less demand characteristics

What are some weaknesses of a field experiment?

- ethical issues, participants don't know that they are participants

- less control

- extraneous variables

What is a natural experiment?

An experiment where the change in the IV is not brought about by the researcher but would have happened even if the researcher had not been there. The researcher records the effect on the DV.

What is the IV in a natural experiment?

Taking advantage of a motivated change of a governing body

What are some strengths of a natural experiment?

- high ecological validity

- demand characteristics aren't a problem

- can be replicated

What are some weaknesses of a natural experiment?

- ethical issues in consent

- lack of control leads to many extraneous variables

What is a quasi experiment?

study of pre-existing conditions (ex: smokers and non-smokers)

What is the IV in a quasi experiment?

Any existing difference between participants and sees how it affects other variables

What type of environment are quasi experiments carried out in?

Can be both a natural or lab environment

All natural experiments are quasi, not all quasi experiments are natural

What are some strengths of a quasi experiment?

- replication is possible

- high internal validity

What are some weaknesses of quasi experiments?

no random allocation is possible, leading to extraneous variables