Detection measures in real-life criminal guilty knowledge tests

J Appl Psychol. 1992 Oct;77(5):757-67. doi: 10.1037/0021-9010.77.5.757.


The present study provides a first attempt to compare the validity of the respiration line length (RLL) and skin resistance response (SRR) amplitude in real-life criminal guilty knowledge tests (GKTs). GKT records of 40 innocent and 40 guilty Ss, for whom actual truth was established by confession, were assessed for their accuracy. When a predefined decision rule was used and inconclusive decisions were excluded, 97.4% of the innocent Ss and 53.3% of the guilty Ss were correctly classified with the SRR measure. For the RLL measure, the respective results were 97.2% and 53.1%. The combination of both measures improved detection of guilty Ss to 75.8% and decreased detection of innocent Ss to 94.1%. The combined measure seems to be a more useful means of identifying guilty suspects than each physiological measure alone. The results elaborate and extend those obtained in a previous field study conducted by Elaad (1990).

MeSH terms

  • Adult
  • Arousal*
  • Criminal Psychology*
  • Guilt*
  • Humans
  • Lie Detection*
  • Male
  • Respiration
  • Theft