Somewhat whimsical informal expression for a tracing pattern sometimes found in the electrodermal channel that is putatively associated with deception. It is the sudden plunging of the electrodermal tracing shortly after the presentation of a relevant question followed by a normal return to baseline, creating the visual impression of a “finger.” The sudden drop and recovery may or may not have been preceded by a phasic response. Some writers have attributed the phenomenon to a loss of contact between the sensors and the skin, such as when certain types of physical countermeasures are practiced. The cause of the phenomenon is not well understood, and it has not been scientifically established as a reliable indicator of deception. Sometimes called the devil’s finger.
