Psychophysiological and behavioral measures for detecting concealed information: the role of memory for crime details

This study examined the role of memory for crime details in detecting concealed information using the electrodermal measure, Symptom Validity Test, and Number Guessing Test. Participants were randomly assigned to three groups: guilty, who committed a mock theft; informed-innocents, who were exposed to crime-relevant items; and uninformed-innocents, who had no crime-relevant information. Participants were tested immediately or 1 week later. Results showed (a) all tests detected the guilty in the immediate condition, and combining the tests improved detection efficiency; (b) tests' efficiency declined in the delayed condition, mainly for peripheral details; (c) no distinction between guilty and informed innocents was possible in the immediate, yet some distinction emerged in the delayed condition. These findings suggest that, while time delay may somewhat reduce the ability to detect the guilty, it also diminishes the danger of accusing informed-innocents.