Interlocutor accommodation of gradually altered nasal signal levels in a model speaker.

BACKGROUND: Phonetic accommodation is observed when interacting speakers gradually converge (or diverge) on phonetic features over the course of a conversation. The present experiment investigated whether gradual changes in the nasal signal levels of a pre-recorded model speaker would lead to accommodation in the nasalance scores of the interlocutor in a speech-shadowing experiment. METHODS: Twenty female speakers in two groups repeated sentences after a pre-recorded model speaker whose nasal signal level was gradually increased or decreased over the course of the experiment. Outcome measures were the mean nasalance scores at the initial baseline, maximum nasal signal level, minimum nasal signal level and final baseline conditions. The order of presentation of the maximum and minimum nasal signal levels was varied between the two groups. RESULTS: The results showed a significant effect of condition in F(3) = 2.86, p = 0.045. Both groups of participants demonstrated lower nasalance scores in response to increased nasal signal levels in the model (phonetic divergence). The group that was first presented with the maximum nasal signal levels demonstrated lower nasalance scores for the minimum nasal signal level condition (phonetic convergence). CONCLUSION: Speakers showed a consistent divergent reaction to a more nasal-sounding model speaker, but their response to a less nasal-sounding model may depend on the order of presentation of the manipulations. More research is needed to investigate the effects of increased versus decreased nasality in the speech of an interlocutor.

The Montclair Map Task: Balance, Efficacy, and Efficiency in Conversational Interaction.

This paper introduces a conversational speech corpus collected during the completion of a map-matching task that is available for research purposes via the Montclair State University Digital Commons Data Repository. The Montclair Map Task is a new, role-neutral conversational task that involves paired iconic maps with labeled landmarks and a path drawn from a start point, around various landmarks, to a finish mark. One advantage of this task-oriented corpus is the ability to derive independent objective measures of task performance for both members of a conversational pair that can be related to aspects of communicative style. A total of 96 native English speakers completed the task in 16 same-sex female, 16 same-sex male, and 16 mixed-sex pairings. Conversations averaged 32 minutes in duration, yielding approximately 217,000 words. The transcription protocol delineates events such as speaking turns, inter-turn intervals, landmark phrases, fillers, pauses, overlaps, and backchannels, making this corpus a useful tool for investigating dynamics of conversational interaction. Analyses of communication efficacy and efficiency reveal that male pairs of talkers were less efficient than female and mixed-sex pairs with respect to partner map-matching task performance.

SHORT-TERM PERCEPTUAL TUNING TO TALKER CHARACTERISTICS.

When a listener encounters an unfamiliar talker, the ensuing perceptual accommodation to the unique characteristics of the talker has two aspects: (1) the listener assesses acoustic characteristics of speech to resolve the properties of the talker's sound production; and, (2) the listener appraises the talker's idiolect, subphonemic phonetic properties that compose the finest grain of linguistic production. A new study controlled a listener's exposure to determine whether the perceptual benefit rests on specific segmental experience. Effects of sentence exposure were measured using a spoken word identification task of Easy words (likely words drawn from sparse neighborhoods of less likely words) and Hard words (less likely words drawn from dense neighborhoods of more likely words). Recognition of words was facilitated by exposure to voiced obstruent consonants. Overall, these findings indicate that talker-specific perceptual tuning might depend more on exposure to phonemically marked consonants than to exposure distributed across the phoneme inventory.

Phonetic convergence across multiple measures and model talkers.

This study consolidates findings on phonetic convergence in a large-scale examination of the impacts of talker sex, word frequency, and model talkers on multiple measures of convergence. A survey of nearly three dozen published reports revealed that most shadowing studies used very few model talkers and did not assess whether phonetic convergence varied across same- and mixed-sex pairings. Furthermore, some studies have reported effects of talker sex or word frequency on phonetic convergence, but others have failed to replicate these effects or have reported opposing patterns. In the present study, a set of 92 talkers (47 female) shadowed either same-sex or opposite-sex models (12 talkers, six female). Phonetic convergence was assessed in a holistic AXB perceptual-similarity task and in acoustic measures of duration, F0, F1, F2, and the F1 × F2 vowel space. Across these measures, convergence was subtle, variable, and inconsistent. There were no reliable main effects of talker sex or word frequency on any measures. However, female shadowers were more susceptible to lexical properties than were males, and model talkers elicited varying degrees of phonetic convergence. Mixed-effects regression models confirmed the complex relationships between acoustic and holistic perceptual measures of phonetic convergence. In order to draw broad conclusions about phonetic convergence, studies should employ multiple models and shadowers (both male and female), balanced multisyllabic items, and holistic measures. As a potential mechanism for sound change, phonetic convergence reflects complexities in speech perception and production that warrant elaboration of the underspecified components of current accounts.

On the perceptual organization of speech.

A general account of auditory perceptual organization has developed in the past 2 decades. It relies on primitive devices akin to the Gestalt principles of organization to assign sensory elements to probable groupings and invokes secondary schematic processes to confirm or to repair the possible organization. Although this conceptualization is intended to apply universally, the variety and arrangement of acoustic constituents of speech violate Gestalt principles at numerous junctures, cohering perceptually, nonetheless. The authors report 3 experiments on organization in phonetic perception, using sine wave synthesis to evade the Gestalt rules and the schematic processes alike. These findings falsify a general auditory account, showing that phonetic perceptual organization is achieved by specific sensitivity to the acoustic modulations characteristic of speech signals.

Is alignment always the result of automatic priming?

Pickering & Garrod's (P&G's) mechanistic theory of dialogue attempts to detail the psychological processes involved in communication that are lacking in Clark's theory. By relying on automatic priming and alignment processes, however, the theory falters when it comes to explaining much of dialogic interaction. We argue for the inclusion of less automatic, though not completely conscious and deliberate, processes to explain such phenomena.

Measuring phonetic convergence in speech production.

Phonetic convergence is defined as an increase in the similarity of acoustic-phonetic form between talkers. Previous research has demonstrated phonetic convergence both when a talker listens passively to speech and while talkers engage in social interaction. Much of this research has focused on a diverse array of acoustic-phonetic attributes, with fewer studies incorporating perceptual measures of phonetic convergence. The current paper reviews research on phonetic convergence in both non-interactive and conversational settings, and attempts to consolidate the diverse array of findings by proposing a paradigm that models perceptual and acoustic measures together. By modeling acoustic measures as predictors of perceived phonetic convergence, this paradigm has the potential to reconcile some of the diverse and inconsistent findings currently reported in the literature.

Auditory-phonetic projection and lexical structure in the recognition of sine-wave words.

Speech remains intelligible despite the elimination of canonical acoustic correlates of phonemes from the spectrum. A portion of this perceptual flexibility can be attributed to modulation sensitivity in the auditory-to-phonetic projection, although signal-independent properties of lexical neighborhoods also affect intelligibility in utterances composed of words. Three tests were conducted to estimate the effects of exposure to natural and sine-wave samples of speech in this kind of perceptual versatility. First, sine-wave versions of the easy and hard word sets were created, modeled on the speech samples of a single talker. The performance difference in recognition of easy and hard words was used to index the perceptual reliance on signal-independent properties of lexical contrasts. Second, several kinds of exposure produced familiarity with an aspect of sine-wave speech: (a) sine-wave sentences modeled on the same talker; (b) sine-wave sentences modeled on a different talker, to create familiarity with a sine-wave carrier; and (c) natural sentences spoken by the same talker, to create familiarity with the idiolect expressed in the sine-wave words. Recognition performance with both easy and hard sine-wave words improved after exposure only to sine-wave sentences modeled on the same talker. Third, a control test showed that signal-independent uncertainty is a plausible cause of differences in recognition of easy and hard sine-wave words. The conditions of beneficial exposure reveal the specificity of attention underlying versatility in speech perception.

Conversational role influences speech imitation.

This study assessed the impact of a conscious imitation goal on phonetic convergence during conversational interaction. Twelve pairs of unacquainted talkers participated in a conversational task designed to elicit between-talker repetitions of the same lexical items. To assess the degree to which the talkers exhibited phonetic convergence during the conversational task, these repetitions were used to elicit perceptual similarity judgments provided by separate sets of listeners. In addition, perceptual measures of phonetic convergence were compared with measures of articulation rates and vowel formants. The sex of the pair of talkers and a talker's role influenced the degree of phonetic convergence, and perceptual judgments of phonetic convergence were not consistently related to individual acoustic-phonetic attributes. Therefore, even with a conscious imitative goal, situational factors were shown to retain a strong influence on phonetic form in conversational interaction.

Amphetamine analogs methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) differentially affect speech.

RATIONALE: Most reports of the effects of methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) on speech have been anecdotal. OBJECTIVES: The current study used a within-participant design to assess the effects of methamphetamine and MDMA on speech. MATERIALS AND METHODS: Eleven recreational users of amphetamines completed this inpatient, within-participant, double-blind study, during which they received placebo, methamphetamine (20, 40 mg), and MDMA (100 mg) on separate days. Following drug administration, study participants described movies viewed the previous evening and completed mood scales. RESULTS: Methamphetamine increased quantity of speech, fluency, and self-ratings of talkativeness and alertness, while it decreased the average duration of nonjuncture unfilled pauses. MDMA decreased fluency and increased self-ratings of inability to concentrate. To determine if methamphetamine- and MDMA-related effects were perceptible, undergraduates listened to the participants' movie descriptions and rated their coherence and the speaker's mood. Following methamphetamine, descriptions were judged to be more coherent and focused than they were following MDMA. CONCLUSIONS: Methamphetamine improved verbal fluency and MDMA adversely affected fluency. This pattern of effects is consistent with the effects of these drugs on functioning in other cognitive domains. In general, methamphetamine effects on speech were inconsistent with effects popularly attributed to this drug, while MDMA-related effects were in agreement with some anecdotal reports and discordant with others.

AUDITORY-PHONETIC PROJECTION AND LEXICAL STRUCTURE IN THE RECOGNITION OF SINE-WAVE WORDS.

Speech remains intelligible despite the elimination of canonical acoustic correlates of phonemes from the spectrum. A portion of this perceptual flexibility can be attributed to modulation sensitivity in the auditory-to-phonetic projection, though signal-independent properties of lexical neighborhoods also affect intelligibility in utterances composed of words. Three tests were conducted to estimate the effects of exposure to natural and sine-wave samples of speech in this kind of perceptual versatility. First, sine-wave versions of the easy/hard word sets were created, modeled on the speech samples of a single talker. The performance difference in recognition of easy and hard words was used to index the perceptual reliance on signal-independent properties of lexical contrasts. Second, several kinds of exposure produced familiarity with an aspect of sine-wave speech: 1) sine-wave sentences modeled on the same talker; 2) sine-wave sentences modeled on a different talker, to create familiarity with a sine-wave carrier; and 3) natural sentences spoken by the same talker, to create familiarity with the idiolect expressed in the sine-wave words. Recognition performance with both easy and hard sine-wave words improved after exposure only to sine-wave sentences modeled on the same talker. Third, a control test showed that signal-independent uncertainty is a plausible cause of differences in recognition of easy and hard sine-wave words. The conditions of beneficial exposure reveal the specificity of attention underlying versatility in speech perception.

On phonetic convergence during conversational interaction.

Following research that found imitation in single-word shadowing, this study examines the degree to which interacting talkers increase similarity in phonetic repertoire during conversational interaction. Between-talker repetitions of the same lexical items produced in a conversational task were examined for phonetic convergence by asking a separate set of listeners to detect similarity in pronunciation across items in a perceptual task. In general, a listener judged a repeated item spoken by one talker in the task to be more similar to a sample production spoken by the talker's partner than corresponding pre- and postinteraction utterances. Both the role of a participant in the task and the sex of the pair of talkers affected the degree of convergence. These results suggest that talkers in conversational settings are susceptible to phonetic convergence, which can mark nonlinguistic functions in social discourse and can form the basis for phenomena such as accent change and dialect formation.