Several different aspects of language use seem to be consistently associated with deception. For some of the strongest associations, such as with immediacy of expression (e.g., using active or passive voice, affirmations or negations), observers’ subjective impressions have been more strongly correlated with deception than the objective measures that have been tested (DePaulo et al., in press). This finding suggests that efforts to design measures for the detection of deception based on language use may have untapped potential.

There have been a few efforts to develop such techniques. For example, one field study (Smith, 2001) evaluated scientific content analysis, developed by Sapir (1987), using statements made by criminal suspects who were later confirmed to be either lying or truthful. This approach can only be applied to written statements made by the suspect without assistance. Trained policemen correctly detected 80 percent of truthful statements and 75 percent of deceptive statements, but experienced policemen not trained in the technique were just as accurate. The study design did not make it possible to tell whether the examiners might have been making judgments based on their own experience rather than by using the principles for the technique. In either case, the study strongly suggests that close examination of how a suspect describes an incident of interest is likely to be fruitful. Pennebaker, Francis, and Booth (2001) and Newman and colleagues (2002) applied a computer program for analyzing five different aspects of language usage (e.g., first person or third person pronouns) to interviews about laboratory lies when the stakes were minimal. The program accurately classified 68 percent of those who lied and 66 percent of those who were truthful.

Another technique for analyzing cues in language is statement validity analysis (Horowitz, 1991; Lamb et al., 1997; Porter and Yuille, 1996; Steller and Koehnken, 1989). This technique, which involves content analysis of in-depth accounts of alleged events, has been used primarily to assess statements of victims or witnesses. There is evidence that credible accounts are more likely to contain an appropriate amount of detail about the alleged event (e,g., Steller and Koehnken, 1989; Porter and Yuille, 1996). Very little research has been done, however, on the technique’s applicability to statements by criminal suspects, some of whom may be unwilling or unable to provide detailed accounts (Porter and Yuille, 1995).

In sum, the available evidence suggests that analysis of language usage and of facial and body movement might be useful in distinguishing lies from truth. It is reasonable to expect that accuracy can be improved by using measures that combine information from several channels (e.g.,