Is speech special? This paper evaluates the evidence that speech perception is distinctive when compared with non-linguistic auditory perception. It addresses the phenomenology, contents, objects, and mechanisms involved in the perception of spoken language. According to the account it proposes, the capacity to perceive speech in a manner that enables understanding is an acquired perceptual skill. It involves learning to hear language-specific types of ethologically significant sounds. According to this account, the contents of perceptual (...) experience when listening to familiar speech are of a variety that is distinctive to hearing spoken utterances. However, perceiving speech involves neither novel perceptual objects nor a unique perceptual modality. Much of what makes speech special stems from our interest in it. (shrink)

What are the factors that contribute to (or inhibit) diachronic sound change? While acoustically motivated sound changes are well documented, research on the articulatory and audiovisual-perceptual aspects of sound change is limited. This paper investigates the interaction of articulatory variation and audiovisual speech perception in the Northern Cities Vowel Shift (NCVS), a pattern of sound change observed in the Great Lakes region of the United States. We focus specifically on the maintenance of the contrast between the vowels /ɑ/ (...) and /ɔ/, both of which are fronted as a result of the NCVS. We present results from two experiments designed to test how the NCVS is produced and perceived. In the first experiment, we present data from an articulatory and acoustic analysis of the production of fronted /ɑ/ and /ɔ/. We find that some speakers distinguish /ɔ/ from /ɑ/ with a combination of both tongue position and lip rounding, while others do so using either tongue position or lip rounding alone. For speakers who distinguish /ɔ/ from /ɑ/ along only one articulatory dimension, /ɑ/ and /ɔ/ are acoustically more similar than for speakers who produce multiple articulatory distinctions. While all three groups of speakers maintain some degree of acoustic contrast between the vowels, the question is raised as to whether these articulatory strategies differ in their perceptibility. In the perception experiment, we test the hypothesis that visual speech cues play a role in maintaining contrast between the two sounds. The results of this experiment suggest that articulatory configurations in which /ɔ/ is produced with unround lips are perceptually weaker than those in which /ɔ/ is produced with rounding, even though these configurations result in acoustically similar output. We argue that these findings have implications for theories of sound change and variation in at least two respects: 1) visual cues can shape phonological systems through misperception-based sound change, and 2) phonological systems may be optimized not only for auditory but also for visual perceptibility. (shrink)

The overall goal of speech perception research is to explain how spoken language is recognized and understood. In the current research framework it is assumed that the key to achieving this overall goal is to solve the lack of invariance problem. But nearly half a century of sustained effort in a variety of theoretical perspectives has failed to solve this problem. Indeed, not only has the problem not been solved, virtually no empirical candidates for solving the problem have (...) been produced. One explanation for this lack of progress is simply that no theory has yet hit upon the correct set of invariant properties. Another explanation is that the goal of solving the lack of invariance problem is itself misguided. The most basic claim of this dissertation is that the latter explanation is correct. ;The lack of progress in explaining speech perception exhibited by the current research framework, I argue, is not, in the first instance, due to the failure of individual theories to solve the lack of invariance problem, but rather to the common background assumption that doing so is in fact the key to explaining speech perception. ;My overall argument in support of this basic claim has three main components: criticism of the empirical results of research in the current framework; criticism of the formulation of theories generated in the current research framework; and the availability of an alternative account of phonetic structure. ;The heart of my argument is an analysis of the character of the theoretical weaknesses of three theories of speech perception: the motor theory of speech perception, the ecological theory of speech perception, and the theory of acoustic invariance. I show that, in each case, the particular theoretical problems result from trying to satisfy the common goal of identifying invariant properties of phonetic percepts. ;I analyze the methodological error embodied in the current approach to explaining speech perception as, in general, one of abstracting the wrong kinds of properties from the detail of the speech event, and, in particular, of abstracting away from dynamic and context-dependent properties. (shrink)

Developmental dyslexia is considered to be most effectively addressed with preventive phonics-based interventions, including grapheme-phoneme coupling and blending exercises. These intervention types require intact speech perception abilities, given their large focus on exercises with auditorily presented phonemes. Yet some children with dyslexia experience problems in this domain due to a poorer sensitivity to rise times, i.e., rhythmic acoustic cues present in the speech envelope. As a result, the often subtle speech perception problems could potentially constrain (...) an optimal response to phonics-based interventions in at-risk children. The current study therefore aimed to extend existing research by examining the presence of potential speech perception deficits in pre-readers at cognitive risk for dyslexia when compared to typically developing peers and to explore the added value of a preventive auditory intervention for at-risk pre-readers, targeting rise time sensitivity, on speech perception and other reading-related skills. To obtain the first research objective, we longitudinally compared speech-in-noise perception between 28 5-year-old pre-readers with and 30 peers without a cognitive risk for dyslexia during the second half of the third year of kindergarten. The second research objective was addressed by exploring growth in speech perception and other reading-related skills in an independent sample of 62 at-risk 5-year-old pre-readers who all combined a 12-week preventive phonics-based intervention with an auditory story listening intervention. In half of the sample, story recordings contained artificially enhanced rise times, while in the other half, stories remained unprocessed. Results revealed a slower speech-in-noise perception growth in the at-risk compared to the non-at-risk group, due to an emerged deficit at the end of kindergarten. Concerning the auditory intervention effects, both intervention groups showed equal growth in speech-in-noise perception and other reading-related skills, suggesting no boost of envelope-enhanced story listening on top of the effect of combining GraphoGame-Flemish with listening to unprocessed stories. These findings thus provide evidence for a link between speech perception problems and dyslexia, yet do not support the potential of the auditory intervention in its current form. (shrink)

Chinese-speaking older adults usually do not perceive a hearing problem until audiometric thresholds exceed 45 dB HL, and the audiometric thresholds of the average hearing-aid user often exceed 60 dB HL. The purpose of this study was to examine the relationships between cognitive and hearing functions in older Chinese adults with HAs and with untreated hearing loss. Participants were 49 Chinese older adults who used HAs and had moderate to severe HL, and 46 older Chinese who had mild to moderately (...) severe HL but did not use HAs. Multiple linear regression analysis was employed to evaluate how well age, education level, audiometric thresholds, and speech perception in noise were related to performance on general cognitive function, working memory, executive function, attention, and verbal learning tests. Results showed that speech perception in noise alone accounted for 13–25% of the variance in general cognitive function, working memory, and executive function in the UT group, and 9–21% of the variance in general cognitive function and verbal learning in the HA group. Audiometric thresholds did not explain any proportion of the variance in cognitive functioning in the HA or UT group. Thus, speech perception in noise accounts for more variance in cognitive performance than audiometric thresholds, and is significantly associated with different cognitive functions in older Chinese adults with HAs and with untreated HL. (shrink)

Older adults with age-related hearing loss exhibit substantial individual differences in speech perception in adverse listening conditions. We propose that the ability to rapidly adapt to changes in the auditory environment is among the processes contributing to these individual differences, in addition to the cognitive and sensory processes that were explored in the past. Seventy older adults with age-related hearing loss participated in this study. We assessed the relative contribution of hearing acuity, cognitive factors, rapid perceptual learning of (...) time-compressed speech, and hearing aid use to the perception of speech presented at a natural fast rate, speech embedded in babble noise, and competing speech. Speech perception was modeled as a function of the other variables. For fast speech, age [odds ratio = 0.79], hearing acuity, pre-learning perception of time-compressed speech, and rapid perceptual learning were all significant predictors. For speech in noise, only hearing and pre-learning perception of time-compressed speech were significant predictors. Consistent with previous findings, the severity of hearing loss and auditory processing was strong contributors to individual differences in fast speech and speech in noise perception. Furthermore, older adults with good rapid perceptual learning can use this capacity to partially offset the effects of age and hearing loss on the perception of speech presented at fast conversational rates. Our results highlight the potential contribution of dynamic processes to speech perception. (shrink)

This book is about the processing of information in face-to-face communication when a speaker makes both audible and visible information available to a perceiver. Both auditory and visual sources of information are evaluated and integrated to achieve speech perception. The evaluation of the information source provides information about the strength of alternative interpretations, rather than just all-or-none categorical information, as claimed by “categorical perception” theory. Information sources are evaluated independently; the integration process insures that the least ambiguous (...) sources have the most influences on the judgment. Similar processes occur in a variety of other behaviors, ranging from personality judgments and categorization to sentence interpretation and decision making. The experimental results are consistent with a fuzzy logical model of perception, positing three operations in perceptual (primary) recognition: feature evaluation, feature integration, and pattern classification. Continuously valued features are first evaluated, then integrated and matched against prototype descriptions in memory; finally, an identification decision is made on the basis of the relative goodness-of-match of the stimulus information with the relevant prototype descriptions. (shrink)

Fodor argues that speech perception is accomplished by a module. Typically, modular processing is taken to be bottom-up processing. Yet there is ubiquitous empirical evidence that speech perception is influenced by top-down processing. Fodor attempts to resolve this conflict by denying that modular processing must be exclusively bottom-up. It is argued, however, that Fodor's attempt to reconcile top-down and modular processing fails, because: (i) it undermines Fodor's own conception of modular processing; and (ii) it cannot account (...) for the contextually varying top-down influences that characterize speech perception. (shrink)

There is a long‐standing project in psychology the goal of which is to explain our ability to perceive speech. The project is motivated by evidence that seems to indicate that the cognitive processing to which speech sounds are subjected is somehow different from the normal processing employed in hearing. The Motor Theory of speech perception was proposed in the 1960s as an attempt to explain this specialness. The first part of this essay is concerned with the (...) Motor Theory's explanandum. It shows that it is rather hard to give a precise account of what the Motor Theory is a theory of. The second part of the essay identifies problems with the theory's explanans: There are difficulties in finding a plausible account of what the content of the Motor Theory is supposed to be. (shrink)

A comparison of Merge, a model of comprehension, and WEAVER, a model of production, raises five issues: merging models of comprehension and production necessarily creates feedback; neither model is a comprehensive account of word processing; the models are incomplete in different ways; the models differ in their handling of competition; as opposed to WEAVER, Merge is a model of metalinguistic behavior.

The suggestion that analytic isomorphism should be rejected applies especially to the domain of speech perception because (1) the guiding assumption that solving the lack of invariance problem is the key to explaining speech perception is a form of analytic isomorphism, and (2) after nearly half a century of research there is virtually no empirical evidence of isomorphism between perceptual experience and lower-level processing units.

Several studies have demonstrated that individuals’ ability to perceive a speech sound contrast is related to the production of that contrast in their native language. The theoretical account for this relationship is that speech perception and production have a shared multimodal representation in relevant sensory spaces. This gives rise to a prediction that individuals with more narrowly defined targets will produce greater separation between contrasting sounds, as well as lower variability in the production of each sound. However, (...) empirical studies that tested this hypothesis, particularly with regard to variability, have reported mixed outcomes. The current study investigates the relationship between perceptual ability and production ability, focusing on the auditory domain. We examined whether individuals’ categorical labeling consistency for the American English /ε/–/æ/ contrast, measured using a perceptual identification task, is related to distance between the centroids of vowel categories in acoustic space and to two measures of production variability: the overall distribution of repeated tokens for the vowels and the proportional within-trial decrease in variability as defined as the magnitude of self-correction to the initial acoustic variation of each token. No significant associations were found between categorical labeling consistency and vowel contrast distance, between categorical labeling consistency and area of the ellipse, or between categorical labeling consistency and centering ratio. These null results suggest that the perception-production relation may not be as robust as suggested by a widely adopted theoretical framing in terms of the size of auditory target regions. However, the present results may also be attributable to choices in implementation that should be subject to further investigation. (shrink)

Hearing loss in old age, which often goes untreated, has far-reaching consequences. Furthermore, reduction of cognitive abilities and dementia can also occur, which also affects quality of life. The aim of this study was to investigate the hearing performance of seniors without hearing complaints with respect to speech perception in noise and the ability to localize sounds. Results were tested for correlations with age and cognitive performance. The study included 40 subjects aged between 60 and 90 years with (...) not self-reported hearing problems. The subjects were screened for dementia. Audiological tests included pure-tone audiometry and speech perception in two types of background noise which was either co-located or spatially separated from the target speech. Sound localization ability was assessed and hearing performance was self-evaluated by a questionnaire. Speech in noise and sound localization was compared with young normal hearing adults. Although considering themselves as hearing normal, 17 subjects had at least a mild hearing loss. There was a significant negative correlation between hearing loss and dementia screening score. Speech perception in noise decreased significantly with age. There were significant negative correlations between speech perception in noise and DemTect score for both spatial configurations. Mean SRTs obtained in the co-located noise condition with amplitude-modulated noise were on average 3.1 dB better than with continuous noise. This gap-listening effect was severely diminished compared to a younger normal hearing subject group. In continuous noise, spatial separation of speech and noise led to better SRTs compared to the co-located masker condition. SRTs in MSNF deteriorated in modulated noise compared to continuous noise by 2.6 dB. Highest impact of age was found for speech perception scores using noise stimuli with temporal modulation in binaural test conditions. Mean localization error was in the range of young adults. Mean amount of front/back confusions was 11.5% higher than for young adults. Speech perception tests in the presence of temporally modulated noise can serve as a screening method for early detection of hearing disorders in older adults. This allows for early prescription of hearing aids. (shrink)

Sussman et al. describe an ecological property of the speech signal that is putatively functional in perception. An important issue, however, is whether their putative cue is an emerging feature or whether the second formant (F2) onset and the F2 vowel actually provide independent cues to perceptual categorization. Regardless of the outcome of this issue, an important goal of speech research is to understand how multiple cues are evaluated and integrated to achieve categorization.

In the verbal domain, there is only very weak evidence favoring the view that working memory is an active state of long-term memory. We strengthen existing evidence by reviewing two recent fMRI studies of verbal working memory, which clearly demonstrate activation in the superior temporal lobe, a region known to be involved in processing speech during comprehension tasks.