Source monitoring errors occur when normal memory recall and perceptual processes are disrupted and a memory error occurs. Source monitoring itself is an unconscious mental test that humans perform in order to determine if a memory is “real” and accurate as opposed to being from an extraneous source like a dream or a movie. People use many sources to determine the source of a memory or idea. When a disruption in source monitoring occurs errors in recall can result as a source monitoring error. These occur when a specific recalled experience is falsely attributed to be the source of a particular memory.
An example of a source monitoring error would be incorrectly recalling a conversation that occurred in a dream as reality. These errors can be caused by brain injury (specifically frontal lobe damage), amnesia, effects of aging, depression, and high stress. Cognitive biases can also cause source monitoring errors. Research by Nancy Franklin has shown that people will recall “reliable” sources as giving desirable information and “unreliable” sources as giving undesirable statements.