THE VOICE OF DECEPTION - VOCAL STRATEGIES OF NAIVE AND ABLE LIARS

The aim of this research was to analyze the main vocal cues and strate gies used by a liar. 31 male university students were asked to raise d oubts in an expert in law about a picture. The subjects were required to describe the picture in three experimental conditions: telling the truth (T) and lying to a speaker when acquiescent (L1) and when suspic ious (L2). The utterances were then subjected to a digitized acoustic analysis in order to measure nonverbal vocal variables. Verbal variabl es were also analyzed (number of words, eloquency and disfluency index ). Results showed that deception provoked an increment in F-0, a great er number of pauses and words, and higher eloquency and fluency indexe s. The F-0 related to the two types of lie-prepared and unprepared-ide ntified three classes of liars: good liars, tense liars (more numerous in L1), and overcontrolled liars (more numerous in L2). It is argued that these differences are correlated to the complex task of lying and the need to control one's emotions during deception. The liar's effor t to control his/her voice, however, can lead to his/her tone being ov ercontrolled or totally lacking in control (leakage). Finally, the res earch forwards an explanation on the strategies used by the good liar and in particular treats the self-deception hypothesis.