The prime method of inquiry in science is the experiment. The key features are control over variables, careful measurement, and establishing cause and effect relationships.
An experiment is an investigation in which a hypothesis is scientifically tested. In an experiment, an independent variable (the cause) is manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled.
An advantage is that experiments should be objective. The views and opinions of the researcher should not affect the results of a study. This is good as it makes the data more valid, and less bias.
Laboratory / Controlled Experiments
This type of experiment is conducted in a well-controlled environment – not necessarily a laboratory – and therefore accurate measurements are possible.
The researcher decides where the experiment will take place, at what time, with which participants, in what circumstances and using a standardized procedure. Participants are randomly allocated to each independent variable group.
An example is Milgram’s experiment on obedience or Loftus and Palmer’s car crash study.
Strength: It is easier to replicate (i.e. copy) a laboratory experiment. This is because a standardized procedure is used. Strength: They allow for precise control of extraneous and independent variables. This allows a cause and effect relationship to be established. Limitation: The artificiality of the setting may produce unnatural behavior that does not reflect real life, i.e. low ecological validity. This means it would not be possible to generalize the findings to a real life setting. Limitation: Demand characteristics or experimenter effects may bias the results and become confounding variables.