An experiment is a research method used by psychologists which involves the manipulation of variables in order to discover cause and effect. It differs from non-experimental methods in that it involves the deliberate manipulation of one variable, the independent variable, while trying to keep all other variables constant. The effect of the manipulation is measured with the dependent variable. 

The two main types of 'true' experiments are laboratory experiments and field experiments.

A quasi experiment is a natural experiment.

When psychologists carry out experiments they use one of three basic experimental designs to investigate the effects of an independent variable on a dependent variable. These are the independent measures design, the repeated measures design and the matched pairs design.

Contributers

Last Updated on 9 December 2009