Research Methods: Types of experiments

What is a laboratory experiment

IV is manipulated and DV is measured in a highly controlled/artificial environment.

What is a field experiment

IV is manipulated and DV is measured in an everyday environment (where participants would be regardless of the research taking place).

What is a natural experiment

IV is naturally occurring (usually a life event or to do with nature and therefore not manipulated by the researcher) and DV is measured

Give an example of a natural experiment

Researchers studying the psychological impact of hurricanes,

E.g. IV that’s naturally occurring

Climate change

What is a quasi experiment

IV is naturally occurring (a pre-existing difference between people like gender, age, disability, and therefore not manipulated by the researcher) and DV is measured.

Quasi experiment example

Researchers asking a child with down syndrome and a child with autism and a child with no mental disability to arrange storybook pictures in order

Field experiment e.g.

Someone collapses on a train filled with ppl to see reactions. 1st time they are holding a walking stick and 2nd group they are holding a beer bottle

Lab experiment e.g.

seeing how long dogs energy last after giving them different types of treats in a lab

Pros and cons of laboratory experiments

P= High internal validity (cuz extraneous variables are controlled so can establish a cause and effect between IV and DV)

high reliability (cuz it uses standardised procedures)

C=Low ecological validity (cuz artificial setting, ppl dont act naturally prone to demand characteristics)

lacks mundane realism (procedures are often odd)

What are the pros and cons of field experiments

P=high ecological validity and mundane realism (cuz it’s done in a natural setting)

Low DC (ppt are usually unaware they’re in a study)

C= Low internal validity (cuz extraneous variables are harder to eliminate)

Ethical issues (ppt usually unaware they’re in a study)

What are the pros and cons of natural experiments

P Allows research to be conducted where it would be unethical for a researcher to manipulate the IV themselves (e.g. abuse victims)

Lets researchers study ‘real’ problems that occur in the world

C= Low internal validity (cuz can’t establish C&E since the IV is not being directly manipulated or controlled by the researcher)

Can only be used where conditions occur naturally so limited opportunities for research.

What are the pros and cons of a quasi experiment

P= High internal validity (to an extent cuz often carried out under controlled conditions so these ‘fake’ experiments share the same strengths as lab exp )

C=Cannot establish cause and effect as the IV is not being directly manipulated or controlled by the researcher. (so the high internal validity to an extent)

Can only be used where conditions are pre-existing differences between people (limits itself)