Do Voice Recordings Reveal whether a Person Is Intoxicated? A Case Study

Abstract

In this report we consider the possibility that speech analysis techniques may be used to determine whether an individual was intoxicated at the time that a voice recording was made, and discuss an analysis of the speech produced by the captain of the Exxon Valdez recorded at several points around the time of the accident at Prince William Sound, Alaska. A review of previous research on the effects of alcohol and other effects on speech production suggests that it may be possible to attribute a certain, unique pattern of changes in speech to the influence of alcohol. However, the rate of occurrence of this pattern or the reliability of a decision based on observations such as these is not known. Acoustic-phonetic analysis of a small number of tokens of Captain Hazelwood's speech recorded before, during and after the accident revealed a number of changes in speech behavior which are similar to the pattern of changes observed in previous laboratorybased research on the effects of alcohol on speech production. We conclude with a discussion of the limitations in making inferences concerning the state of the speaker upon the basis of phonetic data and then discuss several possible explanations of the pattern of change found in the recordings of Captain Hazelwood.In this report, we briefly summarize previous research on the effects of alcohol and other environmental and emotional factors on speech production. We then discuss an analysis of the speech produced by the captain of the Exxon Valdez recorded at several times before, during, and after the accident at Prince William Sound. The tapes that we analyzed and information concerning the communications/recording equipment and the times of the recordings were provided to us by the staff of the National Transportation Safety Board (NTSB). The Problem of Unique SpecificationBefore discussing Captain Hazelwood's speech, we wish to place the present investigation within a general framework. The question which we are attempting to address in this report is whether it is possible to determine if an individual was intoxicated at a particular time based on acoustic analyses of voice recordings. This question hinges crucially on whether there are properties of speech which occur when a speaker (any speaker) is intoxicated and which do not occur in any other circumstance. We will call this the problem of unique specification.Keith Johnson, Department of Linguistics, UCLA, Los Angeles, CA 90024-1543 (USA)The analyses reported in this paper were carried out in connection with the National Transportation Safety Board (NTSB) investigation of the Exxon Valdez accident that occurred on March 24, 1989. This is a revised version of the report which the authors submitted to the NTSB in May 1990. We wish to acknowledge the comments and criticisms of Dr. Malcolm Brenner and our colleagues at Indiana University. NIH Public Access Author ManuscriptPhonetica. Author manuscript; available in PMC 2012 December 18.Published in final edited form as: Phonetica. 1990 ; 47(3-4): 215-237.$wa...

Formal and Empirical Arguments concerning Phonological Acquisition

“…Pseudophonological (i.e., performance-related) effects (like coda devoicing) have been documented among populations other than children. Johnson, Pisoni, and Bernacki (1990) report on the intoxicated speech of the captain of the Exxon Valdez around the time of the accident at Prince William Sound, Alaska. They note, as do authors of other studies of intoxicated speech, that the realization of segments may be affected by intoxication.…”

Judging intoxication

“…Klingholz, Penning, and Liebhardt (1988) examined the ability of an automated statistical program based on several objective measures of speech (e.g., fundamental frequency, signal‐to‐noise ratio) to classify 11 speakers at BAC levels from .05 to .15%. The authors reported high levels of accuracy (95–100%), but cautioned that these figures were dependent on having baseline measures, as individuals differed markedly.…”

Optimality Theory and Language Change

“…Johnson, Pisoni & Bernacki (1990) is an analysis of his speech while drunk.) (Hazelwood was captain of the oil tanker, the Exxon Valdez, which ran aground while he was drunk.…”