types of experiments

what are the 4 types of experiment

laboratory experiments

field experiments

natural experiments 

quasi experiments 

what is a laboratory experiment

an experiment that takes place in a controlled environment where the researcher manipulates the IV and records the effects of the DV  

what is an example of a laboratory experiment from psychology 

asch’s baseline test 

what are the strengths of a lab experiment 

• High control over confounding and extraneous variables.

• High internal validity - researchers can be more certain that IV causes the change in the DV 

• highly replicable due to the high level of control

what are the limitations of a lab experiment 

• low external validity - due to an artificial environment.

• demand characteristics may occur because ppts know they are being tested

• Tasks may lack mundane realism

what is a field experiment

an experiment that takes place in a natural setting where the researcher manipulates the IV and records the effects on the DV

what is an example of a laboratory experiment from psychology 

Hofflin’s study of nurses obedience

what are the strengths of a field experiment 

• Higher mundane realism than lab experiments.

• High external validity

what are the limitations of a field experiment 

• Loss of control over confounding and extraneous variables

• Precise replication is often not possible

• Ethical issues include lack of informed consent and potential invasion of privacy

what is a natural experiment

the change in the IV is not caused by the experimenter but occurs naturally and the effect on the DV is recorded by the experimenter 

what is an example of a natural experiment from psychology 

Romanian orphan study

what are the strengths of a natural experiment 

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

• high external validity because they study real-world issues

what are the limitations of a natural experiment 

• A naturally occurring event is very rare, reducing research opportunities

• he researcher cannot be sure the IV affected the DV due to confounding variables

what is a quasi experiment

where the IV is based off an existing difference between people (this variable hasn’t been manipulated) for example anxiety of someone with a phobia of spiders

what are the strengths of a quasi experiment 

• Are often carried out under controlled conditions, allowing for replication

what are the limitations of a quasi experiment 

• Cannot randomly allocate participants to conditions, so there may be confounding variables.

• The IV is not deliberately changed by the researcher, so we cannot firmly claim that the IV caused any observed change in the DV (low internal validity).