The evolutionary perspective believes that psychological processes echo the evolutionary processes of natural selection. Its method of data collection includes the deduction of explanations for behavior, and comparisons between species and cultures. It also involves a limited amount of experimentation. Of these four perspectives all lend common similarities to the traditional sciences. All have elements of controlled experimentation, as does physics or chemistry.
Cognitive perspectives use computer modeling, as does mathematics.
There are similarities, but there are also differences to any other sciences, such as the study of dreams and fantasies. The methods of experimentation and research in psychology is completed on a scientific basis. Psychological experimental research would involve the manipulation of a situation to examine the way in which the subjects of an experiment react, in order to observe cause and effect. The experimenter manipulates independent variables and the subjects responses would prove the dependant variables. By measuring the subjects responses, the experimenter can tell if the manipulation has had an effect.