Researchers use deception in order to disguise the true purpose of the research. Typically, an explanation of the study is developed that misinforms the participant about the nature of the study, or key information is withheld. This prevents study participants from guessing the hypothesis or responding in a more favorable light than what would be typical.

The use of deception as a control is widespread in some areas of psychology; especially when researchers are studying undesirable social characteristics. Not all psychologists, however, accept the use of deception as it can lead to the expectation that all studies begin with an attempt to "trick" the participant.