Production of Intoxication States by Actors—Acoustic and Temporal Characteristics

Abstract

This paper is the second of a series; the first has been published (J Forensic Sci, 1998;43:1153–62). The goal in the initial pair of experiments was to determine if speakers (actors) could effectively mimic the speech of intoxicated individuals and also volitionally reduce the degradation to their speech that resulted from severe inebriation. To this end, two highly controlled experiments involving 12 actor-speakers were carried out. It was found that, even when sober, nearly all of them were judged drunker (when pretending) than when they actually were severely intoxicated. In the second experiment, they tried to sound sober when highly intoxicated; here most were judged less inebriated than they were. The goal of this second paper is to identify some of the speech characteristics that allowed the subjects to achieve the cited illusions. The focus here is on four paralinguistic factors: fundamental frequency (F0), speaking rate, vocal intensity, and nonfluency level. For the simulation of intoxication study, it was found that F0 was raised along with increased intoxication but raised even more when this state was feigned. A slowing of speaking rate was associated with increasing intoxication, but this shift also was greater when the speaker simulated intoxication. The most striking contrast was found for the nonfluencies; they were doubled for actual intoxication, but quadrupled when intoxication was simulated. On the other hand, the shifts exhibited by the subjects when they attempted to sound sober were not as clear cut. Indeed, no systematic relationships were found here for either F0 or vocal intensity. Both speaking rate and the number of nonfluencies shifted appropriately, but these changes were not statistically significant. In sum, discernable suprasegmental relationships occurred for both studies (but especially the first); further, it is predicted that useful cues also will be found embedded in the segmentals (the sounds of speech).

Perceiving the Effects of Ethanol Intoxication on Voice

“…50 Thus, it is predicted that a voice ''test'' of intoxication would be a more accurate predictor of impairment if the required texts involved the production of extemporaneous and/or other ''difficult'' types of speech. 15,51 This finding is considered to be among the more useful of those resulting from this project.…”

“…This pattern has also been informally observed in other studies, that is, it appears in the companion study 20 and others in this series. 15,19,24 In some cases (yet other studies), it even appears to account for the lack of significance among the independent variables. The authors are planning investigations to determine if this pattern actually exists in studies of this type or is merely a curiosity.…”

“…[13][14][15] Voice and other suprasegmental factors also have been assessed by a number of researchers. 13,[15][16][17][18][19][20][21][22] Some of these authors have reported that speaking fundamental frequency, although variable, is often lowered and its variability may be increased; others have indicated that speaking rate is usually slowed, the number and length of pauses is often increased and amplitude or intensity is sometimes reduced. However, at least one of these relationships is now being challenged: it already has been determined that speaking fundamental frequency will rise (not fall) with increases in intoxication level.…”

“…However, at least one of these relationships is now being challenged: it already has been determined that speaking fundamental frequency will rise (not fall) with increases in intoxication level. 15,19,20 Although the quantitative evaluations of voice patterns have provided useful information about how they are affected by alcohol intoxication, it is the second general domain (perceptual assessment) that is of interest here. Early research in this area also is mixed; most of it involved listeners who were asked to judge the level of intoxication using a ''sober-intoxicated'' continuum or by means of semantic differentials.…”

Voice Disguise in Automatic Speaker Recognition

“…On the other hand, F 1/F 2 was only modified with high levels of alcohol in blood. Other studies concluded that certain changes such as a F 0 raising and a slowing of speaking rate occurred in intoxication -although they were not universal-while no significant changes were found in terms of vocal intensity [Hollien et al 2001b;Hollien et al 2001a], neither in voice onset times of the occlusives /d/ and /t/ [Swartz 1992].…”