Using response time measures to assess "guilty knowledge".

TLDR

Reliable testing of a suspect’s guilt is challenged by the controversial validity of the polygraph and the emergence of event‑related potential methods during memory‑interference tasks. The study extended the memory‑interference paradigm to assess whether response times can accurately detect participants with specific guilty knowledge. Response‑time measures alone reliably distinguished guilty from innocent participants, proved more resistant to strategic manipulation, and suggest a viable alternative to the polygraph.

Abstract

How can a suspect's guilt or innocence be reliably tested? The validity of the polygraph, which measures changes in physiological arousal during a "guilty knowledge" test, is controversial (e.g., T. R. Bashore & P. E. Rapp, 1993; T. P. Cross & L. Saxe, 1992; D. T. Lykken, 1998; J. P. Rosenfeld, 1995; R. Steinbrook, 1992). One alternative to the polygraph examines event-related potentials recorded during a memory interference task (L. A. Farwell & E. Donchin, 1991). The present study extended this paradigm to determine whether response times (RTs) can accurately identify participants possessing specific guilty knowledge. Results from Experiment 1 showed that RT alone can reliably discriminate "guilty" from "innocent" participants. Experiments 2a and 2b indicated that an RT-based paradigm is more resistant to strategic manipulation than previously suggested (Farwell & Donchin, 1991). This RT-based paradigm may be a viable alternative to the polygraph for detecting guilty knowledge.