Independence of lexical context and phonological information in speech perception.

M. A. Pitt (see record 1995-42750-001) studied the joint influence of phonological information and lexical context in W. F. Ganong's (1980) task. Pitt improved on earlier studies by collecting enough observations to make possible the quantitative analyses of an individual's data. The present article shows that the results of such analyses demonstrate that the integration of phonological information and lexical context is very well accounted for by the fuzzy logical model of perception (FLMP). Although Pitt concluded that the results of his research argued against the FLMP in favor of an interactive feedback system, his conclusion was based on an analysis of transformed results. It is argued that this use of a response transformation led to incorrect conclusions and that ultimately, models must be tested directly against observed behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Organization in infant speech perception.

Over the past few years it has become increasingly clear that infants are capable of distinguishing speech contrasts that are differentiated by a single acoustic parameter and, moreover, that they perceive these distinctions in terms of adult phonetic categories. Three experiments with 200 2–4 mo olds examined whether infants also perceive organization in speech, specifically whether they are sensitive not only to individual elements, but also to the combination of elements that comprise basic units. Data show that Ss perceived organization at both the syllabic and segmental levels: Ss noticed the rearrangement of consonants and vowels to form new syllables and the rearrangement of phonetic feature values to form new phonetic segments. These findings provide further support for the assumption that very young infants have quite sophisticated speech perception abilities that constitute an important prerequisite for the acquisition of language. (French abstract) (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laterality in visual speech perception.

The lateralization of visual speech perception was examined in 3 experiments. Participants were presented with a realistic computer-animated face articulating 1 of 4 consonant-vowel syllables without sound. The face appeared at 1 of 5 locations in the visual field. The participants' task was to identify each test syllable. To prevent eye movement during the presentation of the face, participants had to carry out a fixation task simultaneously with the speechreading task. In one study, an eccentricity effect was found along with a small but significant difference in favor of the right visual field (left hemisphere). The same results were found with the face articulating nonlinguistic mouth movements (e.g., kiss). These results suggest that the left-hemisphere advantage is based on the processing of dynamic visual information rather than on the extraction of linguistic significance from facial movements. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Connectionist modeling of speech perception.

Connectionist models of perception and cognition, including the process of deducing meaningful messages from patterns of acoustic waves emitted by vocal tracts, are developed and refined as human understanding of brain function, psychological processes, and the properties of massively parallel architectures advances. The present article presents several important contributions from diverse points of view in the area of connectionist modeling of speech perception and discusses their relative merits with respect to specific theoretical issues and empirical findings. TRACE, the Elman/Norris net, and Adaptive Resonance Theory constitute pivotal points exemplifying overall modeling success, progress in temporal representation, and plausible modeling of learning, respectively. Other modeling efforts are presented for the specific insights they offer, and the article concludes with a discussion of computational versus dynamic modeling of phonological processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locus of selective adaptation in speech perception.

Used the interaural transfer technique in 2 experiments with 19 Ss (aged 18–45 yrs) and 9 Ss (aged 19–34 yrs), respectively, to determine the relative locus of selective adaptation in speech perception. Findings show that voiced (/ba/ or /da/) and voiceless (/pa/ or /ta/) consonants seemed to affect different auditory system loci. On a voice-onset-time continuum (/ba/ to /pa/ or /da/ to /ta/) the selective adaptation effects produced by voiceless consonants were largely ear independent and endured over delays of at least 1 min. However, voiced adapters produced selective adaptation effects that were highly ear specific and relatively short lived (     

The influence of phonological similarity neighborhoods on speech production.

The influence of phonological similarity neighborhoods on the speed and accuracy of speech production was investigated with speech-error elicitation and picture-naming tasks. The results from 2 speech-error elicitation techniques--the spoonerisms of laboratory induced predisposition technique (B. J. Baars, 1992; B. J. Baars & M. T. Motley, 1974; M. T. Motley & B. J. Baars, 1976) and tongue twisters--showed that more errors were elicited for words with few similar sounding words (i.e., a sparse neighborhood) than for words with many similar sounding words (i.e., a dense neighborhood). The results from 3 picture-naming tasks showed that words with sparse neighborhoods were also named more slowly than words with dense neighborhoods. These findings demonstrate that multiple word forms are activated simultaneously and influence the speed and accuracy of speech production. The implications of these findings for current models of speech production are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infant perception of audio-visual speech synchrony.

Three experiments investigated perception of audio-visual (A-V) speech synchrony in 4- to 10-month-old infants. Experiments 1 and 2 used a convergent-operations approach by habituating infants to an audiovisually synchronous syllable (Experiment 1) and then testing for detection of increasing degrees of A-V asynchrony (366, 500, and 666 ms) or by habituating infants to a detectably asynchronous syllable (666 ms; Experiment 2) and then testing for detection of decreasing degrees of asynchrony (500, 366, and 0 ms). Following habituation to the synchronous syllable, infants detected only the largest A-V asynchrony (0 ms vs. 666 ms), whereas following habituation to the asynchronous syllable, infants detected the largest asynchrony (666 ms vs. 0 ms) as well as a smaller one (666 ms vs. 366 ms). Experiment 3 investigated the underlying mechanism of A-V asynchrony detection and indicated that responsiveness was based on a sensitivity to stimulus-energy onsets rather than the dynamic correlation between acoustic and visible utterance attributes. These findings demonstrated that infant perception of A-V speech synchrony is subject to the effects of short-term experience and that it is driven by a low-level, domain-general mechanism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The bounds on flexibility in speech perception.

Dutch listeners were exposed to the English theta sound (as in bath), which replaced [f] in /f/-final Dutch words or, for another group, [s] in /s/-final words. A subsequent identity-priming task showed that participants had learned to interpret theta as, respectively, /f/ or /s/. Priming effects were equally strong when the exposure sound was an ambiguous [fs]-mixture and when primes contained unambiguous fricatives. When the exposure sound was signal-correlated noise, listeners interpreted it as the spectrally similar /f/, irrespective of lexical bias during exposure. Perceptual learning about speech is thus constrained by spectral similarity between the input and established phonological categories, but within those limits, adjustments are thorough enough that even nonnative sounds can be treated fully as native sounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactive use of lexical information in speech perception.

[Correction Notice: An erratum for this article was reported in Vol 13(3) of Journal of Experimental Psychology: Human Perception and Performance (see record 2008-10755-001). In the aforementioned article, Figures 1 and 2 were inadvertently transposed. The figure on p. 294 is actually Figure 2, and the figure on p. 296 is actually Figure 1. The captions are correct as they stand.] Two experiments are reported that demonstrate contextual effects on identification of speech voicing continua. Experiment 1 demonstrated the infuence of lexical knowledge on identification of ambiguous tokens from word–nonword and nonword–word continua. Reaction times for word and nonword responses showed a word advantage only for ambiguous stimulus tokens (at the category boundary); no word advantage was found for clear stimuli (at the continua endpoints). Experiment 2 demonstrated an effect of a postperceptual variable, monetary payoff, on nonword–nonword continua. Identification responses were influenced by monetary payoff, but reaction times for bias-consistent and bias-inconsistent responses did not differ at the category boundary. An advantage for bias-consistent responses was evident at the continua endpoints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Utterance format effects phonological priming in the picture-word task: Implications for models of phonological encoding in speech production.

Picture-word experiments investigating the production of multiword utterances with distractors that are phonologically related to words in noninitial position have yielded inconsistent results, ranging from facilitation to inhibition. A comparison of these studies is complicated by differences in detail. In parallel to the empirical inconsistencies, different theoretical accounts of phonological encoding in speech production have been provided. In the present article, the authors propose a unitary account, which can in principle account for facilitation, null effects, and inhibition. It assumes a graded activation pattern of the elements within the scope of phonological advance planning. The account is tested in an experiment varying utterance format while keeping all other aspects constant. The results are consistent with the proposed unitary account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reflections on the development of speech perception.

The literature on the role of infant–adult comparisons in developmental accounts of speech perception is reviewed, and methodological problems associated with such comparisons are delineated. It is argued that the data that are appropriate for the evaluation of categorical perception in infancy are unavailable. Moreover, the view that language experience operates to eliminate discriminative abilities once present rather than to add abilities once absent is without clear-cut support. The serious confounding of age and method of testing casts doubt on current developmental accounts of speech perception based on comparisons of infant and adult. (French abstract) (87 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing reduced word-forms in speech perception using probabilistic knowledge about speech production.

Two experiments examined how Dutch listeners deal with the effects of connected-speech processes, specifically those arising from word-final /t/ reduction (e.g., whether Dutch [tas] is tas, bag, or a reduced-/t/ version of tast, touch). Eye movements of Dutch participants were tracked as they looked at arrays containing 4 printed words, each associated with a geometrical shape. Minimal pairs (e.g., tas/tast) were either both above (boven) or both next to (naast) different shapes. Spoken instructions (e.g., "Klik op het woordje tas boven de ster,' [Click on the word bag above the star]) thus became unambiguous only on their final words. Prior to disambiguation, listeners' fixations were drawn to /t/-final words more when boven than when naast followed the ambiguous sequences. This behavior reflects Dutch speech-production data: /t/ is reduced more before /b/ than before /n/. We thus argue that probabilistic knowledge about the effect of following context in speech production is used prelexically in perception to help resolve lexical ambiguities caused by continuous-speech processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The perception of speech gestures

Two experiments examined the effects of temporal overlap of speech gestures on the perception of stop consonant clusters. Sequences of stop consonant gestures that exhibit temporal overlap extreme enough to potentially eliminate the acoustic evidence of (at least) one of the consonants were obtained from x-ray microbeam data. Subjects were given a consonant monitoring task using stimuli containing stop sequences as well as those containing single stops. Results showed that (1) the initial consonant in the stop sequences was detected significantly less often than in the single stops; (2) bilabial gestures were considerably more effective at obscuring a preceding alveolar than the reverse; and (3) the detection rate correlated with an index of overlap between lip and tongue tip gestures. Experiment 2 employed stimuli that were truncated during the closure for the critical stop or stop sequence, so as to eliminate any information occurring in the acoustic signal at the stop release. This experiment showed that removing release information decreased detectability of the consonants generally. However, consistent with the observed gestural patterns, removing the release did not decrease detection of the alveolar stop when it was the first consonant of a sequence, indicating that there was no information about the alveolar stop present in acoustic realization of the second stop release. These experiments show that certain gestural patterns actually produced by English speakers may not be completely recoverable by listeners, and further, that it is possible to relate recoverability to particular metric properties of the gestural pattern.     

Hemiface contributions to hemispheric dominance in visual speech perception.

Lateralized displays are used widely to investigate hemispheric asymmetry in language perception. However, few studies have used lateralized displays to investigate hemispheric asymmetry in visual speech perception, and those that have yielded mixed results. This issue was investigated in the current study by presenting visual speech to either the left hemisphere (LH) or the right hemisphere (RH) using the face as recorded (normal), a mirror image of the normal face (reversed), and chimeric displays constructed by duplicating and reversing just one hemiface (left or right) to form symmetrical images (left-duplicated, right-duplicated). The projection of displays to each hemisphere was controlled precisely by an automated eye-tracking technique. Visual speech perception showed the same, clear LH advantage for normal and reversed displays, a greater LH advantage for right-duplicated displays, and no hemispheric difference for left-duplicated displays. Of particular note is that perception of LH displays was affected greatly by the presence of right-hemiface information, whereas perception of RH displays was unaffected by changes in hemiface content. Thus, when investigated under precise viewing conditions, the indications are not only that the dominant processes of visual speech perception are located in the LH but that these processes are uniquely sensitive to right-hemiface information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Function morphemes in young children's speech perception and production.

Function morphemes or functors (e.g., articles and verb inflections) potentially provide children with cues for segmenting speech into constituents, as well as for labeling these constituents (e.g., noun phrase [NP] and verb phrase [VP]). However, the fact that young children often fail to produce functors may indicate that they ignore these cues in early language acquisition. Alternatively, children may be sensitive to functors in perception, but omit them in production. In 3 experiments, 2-year-olds imitated sentences that contained English or non-English functors and that were controlled for both suprasegmental and segmental factors. Children omitted English functors more frequently than non-English functors, indicating perceptual sensitivity to familiar vs unfamiliar elements. The results suggest that children may be able to use functors early in language acquisition to solve the segmentation and labeling problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive control factors in speech perception at 11 months.

The development of speech perception during the 1st year reflects increasing attunement to native language features, but the mechanisms underlying this development are not completely understood. One previous study linked reductions in nonnative speech discrimination to performance on nonlinguistic tasks, whereas other studies have shown associations between speech perception and vocabulary growth. The present study examined relationships among these abilities in 11-month-old infants using a conditioned head-turn test of native and nonnative speech sound discrimination, nonlinguistic object-retrieval tasks requiring attention and inhibitory control, and the MacArthur-Bates Communicative Development Inventory (L. Fenson et al., 1993). Native speech discrimination was positively linked to receptive vocabulary size but not to the cognitive control tasks, whereas nonnative speech discrimination was negatively linked to cognitive control scores but not to vocabulary size. Speech discrimination, vocabulary size, and cognitive control scores were not associated with more general cognitive measures. These results suggest specific relationships between domain-general inhibitory control processes and the ability to ignore variation in speech that is irrelevant to the native language and between the development of native language speech perception and vocabulary. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological evidence on the time course of semantic and phonological processes in speech production.

The temporal properties of semantic and phonological processes in speech production were investigated in a new experimental paradigm using movement-related brain potentials. The main experimental task was picture naming. In addition, a 2-choice reaction go/no-go procedure was included, involving a semantic and a phonological categorization of the picture name. Lateralized readiness potentials (LRPs) were derived to test whether semantic and phonological information activated motor processes at separate moments in time. An LRP was only observed on no-go trials when the semantic (not the phonological) decision determined the response hand. Varying the position of the critical phoneme in the picture name did not affect the onset of the LRP but rather influenced when the LRP began to differ on go and no-go trials and allowed the duration of phonological encoding of a word to be estimated. These results provide electrophysiological evidence for early semantic activation and later phonological encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word frequency effects in speech production: Retrieval of syntactic information and of phonological form.

In 7 experiments the authors investigated the locus of word frequency effects in speech production. Exp 1 demonstrated a frequency effect in picture naming that was robust over repetitions. Exps 2, 3, and 7 excluded contributions from object identification and initiation of articulation. Exps 4 and 5 investigated whether the effect arises in accessing the syntactic word (lemma) by using a grammatical gender decision task. Although a frequency effect was found, it dissipated under repeated access to a word's gender. Exp 6 tested whether the robust frequency effect arises in accessing the phonological form (lexeme) by having Ss translate words that produced homophones. Low-frequent homophones behaved like high-frequent controls, inheriting the accessing speed of their high-frequent homophone twins. Because homophones share the lexeme, not the lemma, this suggests a lexeme-level origin of the robust effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes across childhood in the perception of non-native speech sounds.

Tested 12 English-speaking children at each of 3 ages (4, 8, and 12 yrs) on 3 speech contrasts of English and Hindi sounds. As a control procedure, 2 bilingual Hindi–English speaking children (aged 4 and 5 yrs) were also tested. Results show that the loss of ability to discriminate the nonnative (Hindi) speech contrasts was evident by 4 yrs of age, suggesting that important reorganizations in linguistic perceptual abilities occur in early childhood. Results support the notion that learning a 2nd language may not necessarily be easier in young childhood. (French abstract) (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-language speech perception: Initial capabilities and developmental change.

This article reports three studies designed to increase our understanding of developmental changes in cross-language speech perception. In the first study, we compared adult speakers of English and Hindi on their ability to discriminate pairings from a synthetic voiced, unaspirated place-of-articulation continuum. Results indicated that English listeners discriminate two categories (ba vs. da), whereas Hindi listeners discriminate three (ba vs. da, and da vs. DA). We then used stimuli from within this continuum in the next two experiments to determine (a) if our previously reported finding (Werker & Tees, 1984a) of a reorganization between 6 and 12 months of life from "universal" to "language-specific" phonetic perception would be evident using synthetic (rather than natural) stimuli in which the physical variability within and between categories could be controlled, and (b) whether the younger infants' sensitivity to nonnative speech contrasts is best explained by reference to the phonetic relevance or the physical similarity of the stimuli. In addition to replicating the developmental reorganization, the results indicate that infant speech perception is phonetically relevant. We discuss the implications of these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)