What term is used in psychology to describe a person who is an actor playing a specific role as part of an experiment?

The term "confederate" is used in psychology to refer specifically to an actor who takes on a role in an experiment, often to manipulate social situations or interactions without the knowledge of the actual participants. Confederates are typically employed to facilitate the research by creating controlled interactions or conditions, which helps in studying specific psychological phenomena. Their presence can be critical in experiments where the behavior of real participants is measured in response to these actors.

Using a confederate allows researchers to assess responses in a more naturalistic setting or to ensure a particular dynamic is present during the experiment. This controlled approach supports the validity of the findings by ensuring that key variables are actively represented in the research process.