Perception of speech reflects optimal use of probabilistic speech cues

Listeners are exquisitely sensitive to fine-grained acoustic detail within phonetic categories for sounds and words. Here we show that this sensitivity is optimal given the probabilistic nature of speech cues. We manipulated the probability distribution of one probabilistic cue, voice onset time (VOT), which differentiates word initial labial stops in English (e.g., "beach" and "peach"). Participants categorized words from distributions of VOT with wide or narrow variances. Uncertainty about word identity was measured by four-alternative forced-choice judgments and by the probability of looks to pictures. Both measures closely reflected the posterior probability of the word given the likelihood distributions of VOT, suggesting that listeners are sensitive to these distributions.     

Stimulus-response compatibility in the programming of speech

Subjects chose between sequences of one syllable (e.g.,/gi/vs./bi/), two syllables (e.g.,/gibi/ vs./gubu/), and three syllables (e.g.,/gibidi/ vs. gubudu/), when/i/sequences were signaled by high-pitched tones and/u] sequences were signaled by low-pitched tones (high compatibility), or the reverse (low compatibility). Choice times were additively affected by sequence length and compatibility. A second experiment showed attenuated compatibility effects for sequences with different vowels in the first and second syllables. These results replicate previously reported results for choices between finger sequences, which suggests that the same programming methods are used in both output domains. Evidently, choices between response sequences can be achieved by selecting a distinguishing parameter and assigning it in a serial fashion to partially prepared motor subprograms.     

Motor activation from visible speech: evidence from stimulus response compatibility

In speech perception, phonetic information can be acquired optically as well as acoustically. The motor theory of speech perception holds that motor control structures are involved in the processing of visible speech, whereas perceptual accounts do not make this assumption. Motor involvement in speech perception was examined by showing participants response-irrelevant movies of a mouth articulating /ba/ or /da/ and asking them to verbally respond with either the same or a different syllable. The letters "Ba" and "Da" appeared on the speaker's mouth to indicate which response was to be performed. A reliable interference effect was observed. In subsequent experiments, perceptual interference was ruled out by using response-unrelated imperative stimuli and by preexposing the relevant stimulus information. Further, it was demonstrated that simple directional features (opening and closing) do not account for the effect. Rather, the present study provides evidence for the view that visible speech is processed up to a late, response-related processing stage, as predicted by the motor theory of speech perception.     

The use of sequential probabilities in the segmentation of speech

The present investigation addresses the possible utility of sequential probabilities in the segmentation of spoken language. In a series of five word- spotting and two control lexical decision experiments, high- versus low-probability consonant-vowel (Experiments 1, 2, 5, and 7) and vowel-consonant (Experiments 1, 3, 4, and 6) strings were presented either in the nonsense contexts of target words (Experiments 1-3) or within the target words themselves (Experiments 4-7). The results suggest that listeners, at least for sequences in the onset position, indeed use sequential probabilities as cues for segmentation. The probability of a sound sequence influenced segmentation more when the sequence occurred within the target words (Experiments 4-7 vs. Experiments 1-3). Furthermore, the effects were reliable only when the sequences occurred in the onset position (Experiments 1, 2, 5, and 7 vs. Experiments 1, 3, 4, and 6).     

The use of sequential probabilities in the segmentation of speech

The present investigation addresses the possible utility of sequential probabilities in the segmentation of spoken language. In a series of five word- spotting and two control lexical decision experiments, high- versus low-probability consonant-vowel (Experiments 1, 2, 5, and 7) and vowel-consonant (Experiments 1, 3, 4, and 6) strings were presented either in the nonsense contexts of target words (Experiments 1–3) or within the target words themselves (Experiments 4–7). The results suggest that listeners, at least for sequences in the onset position, indeed use sequential probabilities as cues for segmentation. The probability of a sound sequence influenced segmentation more when the sequence occurred within the target words (Experiments 4–7 vs. Experiments 1–3). Furthermore, the effects were reliable only when the sequences occurred in the onset position (Experiments 1, 2, 5, and 7 vs. Experiments 1, 3, 4, and 6).     

Time flies like an arrow: Space-time compatibility effects suggest the use of a mental timeline

The concept of time is elusive to direct observation, yet it pervades almost every aspect of our daily lives. How is time represented, given that it cannot be perceived directly? Metaphoric mapping theory assumes that abstract concepts such as time are represented in terms of concrete, readily available dimensions. Consistent with this, many languages employ spatial metaphors to describe temporal relations. Here we investigate whether the timeis-space metaphor also affects visuospatial attention. In a first experiment, subjects categorized the names of actors in a manner compatible or incompatible with the orientation of a timeline. In two further experiments, subjects categorized or detected left- or right-side targets following prospective or retrospective time words. All three experiments show compatibility effects between the dimensions of space (left-right) and time (earlier-later) and indicate that the concept of time does indeed evoke spatial associations that facilitate responses to targets at spatially compatible locations.     

Potential perceptual bases for successful use of a vibrotactile speech perception aid

This paper examines the possibility that perception of vibrotactile speech stimuli is enhanced in adults with early and life-long use of hearing aids. We present evidence that vibrotactile aid benefit in adults is directly related to the age at which the hearing aid was fitted and the duration of its use. The stimulus mechanism responsible for this effect is hypothesized to be long-term vibrotactile stimulation by high powered hearing aids. We speculate on possible mechanisms for enhanced vibrotactile speech perception as the result of hearing aid use: (1) long-term experience receiving degraded or impoverished speech stimuli results in a speech processing system that is more effective for novel stimuli, independent of perceptual modality; and/or (2) long-term sensory/perceptual experience causes neural changes that result in more effective delivery of speech information via somatosensory pathways.     

The active use of grammar in speech perception

Judgments of the location of short bursts of noise in sentences were used to reveal perceptual segmentation of sentences. It was assumed that segmentation would correspond to major constituent boundaries. In order to control for correlated variables of pitch and intonation, identical acoustic material was provided with alternate constituent structures. It was found that differences in response to identical strings were predicted by the points of variation in constituent structure.     

The use of rhythm in attending to speech

Three experiments examined attentional allocation during speech processing to determine whether listeners capitalize on the rhythmic nature of speech and attend more closely to stressed than to unstressed syllables. Ss performed a phoneme monitoring task in which the target phoneme occurred on a syllable that was either predicted to be stressed or unstressed by the context preceding the target word. Stimuli were digitally edited to eliminate the local acoustic correlates of stress. A sentential context and a context composed of word lists, in which all the words had the same stress pattern, were used. In both cases, the results suggest that attention may be preferentially allocated to stressed syllables during speech processing. However, a normal sentence context may not provide strong predictive cues to lexical stress, limiting the use of the attentional focus.     

A meta-analytic review of gender variations in children's language use: talkativeness, affiliative speech, and assertive speech

Three sets of meta-analyses examined gender effects on children's language use. Each set of analyses considered an aspect of speech that is considered to be gender typed: talkativeness, affiliative speech, and assertive speech. Statistically significant average effect sizes were obtained with all three language constructs. On average, girls were slightly more talkative and used more affiliative speech than did boys, whereas boys used more assertive speech than did girls. However, the average effect sizes were either negligible (talkativeness, d=0.11; assertive speech, d=0.11) or small (affiliative speech, d=0.26). Larger effect sizes were indicated for some language constructs depending on either the operational definition of the language measure, the method of recording, the child's age level, the interaction partner (adult or peer), group size, gender composition, observational setting, or type of activity. The results are interpreted in relation to social-developmental and social-constructionist approaches to gender; these views are presented as complementary--rather than competing--meta-theoretical viewpoints.     

Musical notation for the keyboard: An examination of stimulus-response compatibility

A recent stimulus-response compatibility model was used to provide a performance evaluation of an experimental notation for the keyboard in which pitch varies horizontally in visual space. One hundred and twenty subjects performed a choice reaction time task using either the horizontal notation or a more traditional vertical notation. Half the subjects in each notation group received white noise and half received pitch-varying feedback with responses. A horizontal display advantage was revealed when rules of the model were applied to data analyses. Further, the horizontal display advantage was not dependent on the nature of the feedback. In a second experiment, performance of musicians and non-musicians was compared using the horizontal and vertical notations. Musicians' performance was uniformly better than that of non-musicians, and did not differ with notation orientation. The findings support the use of non-traditional horizontal notations for novice performance on a keyboard instrument.     

The effects of speech output technology in the learning of graphic symbols

The effects of auditory stimuli in the form of synthetic speech output on the learning of graphic symbols were evaluated. Three adults with severe to profound mental retardation and communication impairments were taught to point to lexigrams when presented with words under two conditions. In the first condition, participants used a voice output communication aid to receive synthetic speech as antecedent and consequent stimuli. In the second condition, with a nonelectronic communications board, participants did not receive synthetic speech. A parallel treatments design was used to evaluate the effects of the synthetic speech output as an added component of the augmentative and alternative communication system. The 3 participants reached criterion when not provided with the auditory stimuli. Although 2 participants also reached criterion when not provided with the auditory stimuli, the addition of auditory stimuli resulted in more efficient learning and a decreased error rate. Maintenance results, however, indicated no differences between conditions. Finding suggest that auditory stimuli in the form of synthetic speech contribute to the efficient acquisition of graphic communication symbols.     

Justice and forgiveness: Experimental evidence for compatibility

A 3 (justice prime: restorative, retributive, no prime) × 3 (contextual prime: criminal justice system, intimate relationship, workplace) experimental design was used with 173 participants reading hypothetical transgression scenarios to test the hypothesis that people associate forgiveness more with restorative justice than with retributive justice, and that such relationships hold regardless of the social context. As predicted, there were main effects for justice prime, with participants more likely to associate benevolent responding, and less likely to associate revenge and avoidant responses, with restorative justice than with retributive justice. They were also more likely to associate benevolence, and less likely to associate revenge and avoidant responses, with intimate relationships than with criminal justice and the workplace. Also as predicted, there was no interaction between justice and context for benevolence and revenge. Although one should be cautious about extrapolating from ‘no difference’ hypotheses, these results provide some indication that the forgiveness-justice relationship may be generalised beyond the criminal justice system.     

A meta-analytic review of gender variations in adults' language use: talkativeness, affiliative speech, and assertive speech.

Three separate sets of meta-analyses were conducted of studies testing for gender differences in adults' talkativeness, affiliative speech, and assertive speech. Across independent samples, statistically significant but negligible average effects sizes were obtained with all three language constructs: Contrary to the prediction, men were more talkative (d = -.14) than were women. As expected, men used more assertive speech (d = .09), whereas women used more affiliative speech (d = .12). In addition, 17 moderator variables were tested that included aspects of the interactive context (e.g., familiarity, gender composition, activity), measurement qualities (e.g., operational definition, observation length), and publication characteristics (e.g., author gender, publication source). Depending on particular moderators, more meaningful effect sizes (d > .2) occurred for each language construct. In addition, the direction of some gender differences was significantly reversed under particular conditions. The results are interpreted in relation to social-constructionist, socialization, and biological interpretations of gender-related variations in social behavior.     

Metatechnology: A technollogy for the safe,effective, and economical use of technology

Alarmed by Three Mile Island, Love Canal, and other disastrous deployments of new technologies, the public is demanding more voice in the decision-making on technology. To make this possible, it is proposed that metatechnology be evolved that will provide a practical technology for the safe, effective, and economical use of technology. A case history of a specific metatechnology is presented. Here the metatechnology enabled a realistic balancing of the benefits of mass screening of women by mammography against the hazards from the X-rays. By showing that the screening of women under 50 was counterproductive, this metatechnology helped to ban such screening in a program involving a quarter of a million women. The strategic mistake in setting up this and other technological programs was that the decisions were made by the technologists. They benefited the technologists but were not beneficial to the women. One of the potentials of metatechnology is that in its fully computerized versions it could be used directly by the public for decision-making on the deployment of technologies.