Differences in Word Usage by Truth Tellers and Liars in Written Statements and an Investigative Interview After a Mock Crime

Although much is known about word usage differences between truths and lies, most of the research to date involves an examination of truths and lies in low stakes situations, written statements or interviews but not both, and native speakers of a single language. We examined differences in word usage between truth tellers and liars in a moderately high stakes, real-life scenario (mock crime) involving participants from four cultural/ethnic groups—European-Americans, Chinese, Hispanics and Middle Easterners. Each participant produced a written statement and participated in an investigative interview; word usage in both was analyzed. Word usage differentiated truths from lies in both the written statement and the investigative interview, and the effect sizes associated with these findings were substantial. For the written statement, word usage predicted truths from lies at 68.90% classification accuracy; for the investigative interview, word usage predicted truths from lies at 71.10% accuracy. Ethnicity did not moderate these effects. These findings are discussed in terms of their implications to cross-cultural applicability of the psychological demands placed on liars and in terms of their practical field utility. Copyright © 2014 John Wiley & Sons, Ltd.