Perceptual flexibility: Maintenance or recovery of the ability to discriminate non-native speech sounds.

Examined the influence of prior training and linguistic experience on the perception of nonnative speech in 2 experiments. Exp I assessed the effect of laboratory training on the ability of 30 English-speaking adults (aged 18–35 yrs) to discriminate 2 speech contrasts that are used to contrast meaning in Hindi but not in English. Short-term training resulted in an amelioration of the initial poor performance of Ss in discriminating a nonnative voicing contrast, but training had no such effect in the case of a Hindi contrast involving a place of articulation distinction. In Exp II, the performance of 3 groups of English-speaking adults (aged 20–38 yrs)—Ss who had studied Hindi for 5 yrs or more, Ss who were studying Hindi as a 2nd language with early experience of Hindi, and Ss studying Hindi as a 2nd language with no early experience of Hindi—was examined to investigate the effect of studying Hindi as a 2nd language for different periods. Ss who had studied Hindi for at least 5 yrs discriminated both Hindi speech contrasts. While 1 yr of 2nd language experience also improved performance of Ss with no early Hindi experience on the voicing contrast, it had little influence on their ability to discriminate the Hindi place contrast. Ss who had early experience hearing the contrasts being used, but no further exposure, could discriminate both the voicing and place distinctions prior to language study. Findings are discussed in terms of the recovery and maintenance of linguistic perceptual ability. (French abstract) (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examination of perceptual reorganization for nonnative speech contrasts: Zulu click discrimination by English-speaking adults and infants.

The language environment modifies the speech perception abilities found in early development. In particular, adults have difficulty perceiving many nonnative contrasts that young infants discriminate. The underlying perceptual reorganization apparently occurs by 10–12 months. According to one view, it depends on experiential effects on psychoacoustic mechanisms. Alternatively, phonological development has been held responsible, with perception influenced by whether the nonnative sounds occur allophonically in the native language. We hypothesized that a phonemic process appears around 10–12 months that assimilates speech sounds to native categories whenever possible; otherwise, they are perceived in auditory or phonetic (articulatory) terms. We tested this with English-speaking listeners by using Zulu click contrasts. Adults discriminated the click contrasts; performance on the most difficult (80% correct) was not diminished even when the most obvious acoustic difference was eliminated. Infants showed good discrimination of the acoustically modified contrast even by 12–24 months. Together with earlier reports of developmental change in perception of nonnative contrasts, these findings support a phonological explanation of language-specific reorganization in speech perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in perception of nonnative vowel contrasts.

Discrimination of 2 German vowel contrasts was examined in English-learning infants of 6–8 and 10–12 mo of age using a head turn procedure. The younger infants were better able than the older infants to discriminate the nonnative contrasts, but performance at 6–8 mo was below levels that have been reported for nonnative consonant contrasts. A 2nd experiment using a habituation looking procedure showed that 4-mo-old infants discriminated both German vowel contrasts, but the 6-mo-olds could not. The findings are consistent with previous consonant work, revealing a shift from a language-general toward a language-specific pattern during the 1st yr of life. However, that shift begins earlier in development for vowels than for consonants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of vocalic cues to consonant voicing and native language background: the influence of experimental design

For native speakers of English and several other languages, preceding vocalic duration and F1 offset frequency are two of the cues that convey the stop consonant voicing distinction in word-final position. For speakers learning English as a second language, there are indications that use of vocalic duration, but not F1 offset frequency, may be hindered by a lack of experience with phonemic (i.e., lexical) vowel length (the "phonemic vowel length account": Crowther & Mann, 1992). In this study, native speakers of Arabic, a language that includes a phonemic vowel length distinction, were tested for their use of vocalic duration and F1 offset in production and perception of the English consonant-vowel-consonant forms pod and pot. The phonemic vowel length hypothesis predicts that Arabic speakers should use vocalic duration extensively in production and perception. On the contrary, Experiment 1 revealed that, consistent with Flege and Port's (1981) findings, they produced only slightly (but significantly) longer vocalic segments in their pod tokens. It further indicated that their productions showed a significant variation in F1 offset as a function of final stop voicing. Perceptual sensitivity to vocalic duration and F1 offset as voicing cues was tested in two experiments. In Experiment 2, we employed a factorial combination of these two cues and a finely spaced vocalic duration continuum. Arabic speakers did not appear to be very sensitive to vocalic duration, but they were about as sensitive as native English speakers to F1 offset frequency. In Experiment 3, we employed a one-dimensional continuum of more widely spaced stimuli that varied only vocalic duration. Arabic speakers showed native-English-like sensitivity to vocalic duration. An explanation based on the perceptual anchor theory of context coding (Braida et al., 1984; Macmillan, 1987; Macmillan, Braida, & Goldberg, 1987) and phoneme perception theory (Schouten & Van Hessen, 1992) is offered to reconcile the apparently contradictory perceptual findings. The explanation does not attribute native-English-like voicing perception to the Arabic subjects. The findings in this study call for a modification of the phonemic vowel length hypothesis.     

A modification of play audiometry to assess speech discrimination ability in severe-profoundly deaf 2- to 4-year-old children

OBJECTIVE: The aim was to develop an assessment procedure that was independent of language and speech production ability, to test speech feature discrimination in severe-profoundly deaf children 2 to 4 yr of age. DESIGN: The procedure being trialed was adapted from existing procedures. The child was required to respond with a game-like motor response to a "change" in a speech stimulus that was being presented repeatedly through a speaker. The change occurred at randomly determined times, and false alarm responses were measured during the waiting periods (while the child waited for the change). Two- to four-yr-old normally hearing children and hearing-impaired children using hearing aids and a group of 4-yr-old hearing-impaired children using cochlear implants were assessed on the task. RESULTS: More than 82% of the 3- and 4-yr-old normally hearing and hearing-impaired children were able to complete the testing for the eight speech sound contrasts within three 20 minute sessions. Fifty percent of the 2-yr-old normally hearing and hearing-impaired children were able to condition and complete the task. All of the normally hearing children who completed the task successfully discriminated all speech sound contrasts. The performance of the hearing-impaired children using hearing aids was influenced by the degree of hearing loss and the type of speech contrast being tested. Similarly, the average performance of the children using cochlear implants was better for easier contrasts such as /ba/bi/ with contrasting vowel formant cues. CONCLUSIONS: This procedure has potential for use as a reliable clinical and research tool for assessing the development of auditory discrimination ability in 2- to 4-yr-old severe-profoundly deaf children.     

Temporal encoding as a determinant of overshadowing

OBJECTIVE: To examine changes over time in consonant feature production by children with profound hearing impairments who used either the Nucleus multichannel cochlear implant or the multichannel vibrotactile aid, Tactaid 7. DESIGN: Imitative consonant productions of children with prelingual deafness were elicited and transcribed at two intervals: 1) before receiving their respective devices (predevice interval), and 2) after an average of 1.5 yr of device use (postdevice interval). The consonant productions were analyzed in terms of the percentage of consonant features (manner, place, and voicing) produced by the child that matched the features of the examiner's target. The percentage of features produced correctly was then averaged across repetitions, vowel environments, and participants within each group. RESULTS: At the predevice interval, the cochlear implant and Tactaid 7 participants demonstrated similar imitative consonant production abilities. After an average of 1.5 yr of device use, the cochlear implant participants demonstrated significantly greater gains than did the Tactaid 7 participants for the features of voicing and place of articulation. Although the cochlear implant participants showed a trend towards better production of the consonant manner features, this difference failed to reach significance. CONCLUSIONS: The current results suggest that the use of a multichannel sensory aid yields improvements in consonant feature production. Furthermore, use of a cochlear implant appears to promote the production of consonant voicing and place features to a greater degree than does the use of a multichannel tactile aid.     

Effect of time and frequency manipulation on syllable perception in developmental dyslexics

Many people with developmental dyslexia have difficulty perceiving stop consonant contrasts as effectively as other people and it has been suggested that this may be due to perceptual limitations of a temporal nature. Accordingly, we predicted that perception of such stimuli by listeners with dyslexia might be improved by stretching them in time-equivalent to speaking slowly. Conversely, their perception of the same stimuli ought to be made even worse by compressing them in time-equivalent to speaking quickly. We tested 15 children with dyslexia on their ability to identify correctly consonant-vowel-consonant (CVC) stimuli that had been stretched or compressed in the time domain. We also tested their perception of the same CVC stimuli after the formant transitions had been stretched or compressed in the frequency domain. Contrary to our predictions, we failed to find any systematic improvement in their performance with either manipulation. We conclude that simple manipulations in the time and frequency domains are unlikely to benefit the ability of people with dyslexia to discriminate between CVCs containing stop consonants.     

Categorization of speech by infants: Support for speech-sound prototypes.

This study tested 6-month-old infants' categorization of speech stimuli to investigate whether infants organize speech categories around "prototypes." In Experiment 1, infants first discriminated single "good" exemplars from two different vowel categories. They were then tested with 64 novel exemplars, 32 from each vowel category. The test stimuli varied in the degree to which they conformed to adult-defined prototypes of the two categories. The results showed that infants correctly sorted the novel stimuli over 90% of the time. In Experiment 2, we trained two groups of infants, one with a good (prototypical) exemplar from a vowel category and the other with a poor (nonprototypical) exemplar. Then we tested both groups with 16 novel exemplars from that same vowel category. Generalization to novel members of the category was significantly greater following exposure to the prototypical exemplar. Results are consistent with a model of speech perception that holds that young human infants organize vowel categories around prototypes. This may contribute to their seemingly efficient processing of speech information, even in the first half year of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual probability evaluation in autistic, receptive developmental language disorder, and control children: event-related brain potential evidence

Compared 8- to 14-year-old children with either autism or receptive developmental language disorder (RDLD) to age- and IQ-matched normal controls in their ability to detect both frequent (p = .70) and infrequent (p = .30) randomly presented auditory stimuli under task and no-task conditions. Event-related brain potentials (ERPs), behavioral reaction times, and target detection accuracy rates were measured. Although the three groups of children performed in a similar manner on behavioral measures, only the children with autism demonstrated an abnormally small amplitude of the P3b, a component of the ERP. This result is interpreted in terms of (a) the consistency of this finding with other ERP studies involving older individuals with autism; and (b) its significance with respect to the difficulty children with autism have in modifying their expectancies to contextually relevant sequences of auditory information.     

Voice onset time in speech produced by inexperienced signers during simultaneous communication

This study investigated sentence duration and voice onset time (VOT) of plosive consonants in words produced during simultaneous communication (SC) by inexperienced signers. Stimulus words embedded in a sentence were produced with speech only and produced with SC by 12 inexperienced sign language users during the first and last weeks of an introductory sign language course. Results indicated significant differences between the speech and SC conditions in sentence duration and VOT of initial plosives at both the beginning and the end of the class. Voiced/voiceless VOT contrasts were enhanced in SC but followed English voicing rules and varied appropriately with place of articulation. These results are consistent with previous findings regarding the influence of rate changes on the temporal fine structure of speech (Miller, 1987) and were similar to the voicing contrast results reported for clear speech by Picheny, Durlach, and Braida (1986) and for experienced signers using SC by Schiavetti, Whitehead, Metz, Whitehead, and Mignerey (1996).     

Auditory short-term memory and digit span: Normal versus poor readers.

Investigated the relationship between reading comprehension level, digit span, and short-term memory for Morse codelike temporal patterns in 3 experiments. Consistent with previous research on children, Exp I using 60 undergraduates demonstrated that Ss performed better when the 1st pattern was auditory than when it was visual or tactual. In Exps II and III with 36 undergraduates and 98 5th graders, respectively, no relationship was found between digit span and accuracy in comparing patterns of tones presented a few seconds apart. However, both tasks discriminated between children with normal and poor reading comprehension scores on a standardized test (Reading Comprehension subtest of the California Achievement Tests). It appears that these 2 tasks index fundamental processes that underlie reading comprehension. Digit span seems to assess an individual's ability to rapidly develop meaningful codes in memory for incoming verbal stimuli. The auditory pattern comparison procedure appears to measure ability to maintain information in short-term memory. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effet des stimuli écologiques et des programmes de renforcement sur les comportements exploratoires et ludiques de l'enfant.

Analyzed functional relationships between children's exploratory and play behaviors, and stimuli elicited by a novel object in a familiar setting. In Exp I, a wooden duck was presented to 4 groups of 3–5 yr olds. Manipulation of the duck's tail elicited, according to groups, tactile–visual, tactile–auditory, or tactile–visual–auditory stimulations. In Exp II, an intermittent schedule of reinforcement was implemented to examine variations of responses in the tactile–auditory condition. Results indicate variations in the manipulatory response and in the 3 classes of observed behaviors. Tactile–visual–auditory stimulations elicited a maximum of behaviors associated with the novel object and an exponential decrease of manipulatory responses after 2 sessions. The intermittent schedule, in the tactile–auditory condition, elicited behaviors relatively similar to those observed in the tactile–visual–auditory condition. Ecological stimuli affected differently the operant response, as well as other classes of behaviors. The difficulty, and probably the uselessness, of a differentiation between exploration and play is underlined in the discussion. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methods to assess the development and recovery of locomotor function after spinal cord injury in rats

Recovery of comprehension and total language in 22 Wernicke's aphasics was correlated with lesion size and extent of involvement of certain structures on CT. Recovery rates and outcomes were separately examined using 0-3 months and 0-12 months poststroke language data. Quantitative measures of structural damage were regressed on total aphasia and comprehension outcome measures. Supramarginal and angular gyri appeared to be the most significant structures in recovery in addition to initial severity and lesion size. This was confirmed by using ANOVA to compare the extent of involvement in each postcentral structure among the poor, moderate, and good recovery groups. The superior temporal and middle temporal gyri are less involved in the good recovery group. Structures posteriorly adjacent to Wernicke's area are important for compensation in Wernicke's aphasia and in the accompanying comprehension deficit. Persisting Wernicke's aphasia usually involves the supramarginal and angular gyri in addition to the superior temporal area.     

Information processing by school-age children with specific language impairment: evidence from a modality effect paradigm

School-age children with specific language impairment (SLI) and age-matched controls were tested for immediate recall of digits presented visually, auditorily, or audiovisually. Recall tasks compared speaking and pointing response modalities. Each participant was tested at a level that was consistent with her or his auditory short-term memory span. Traditional effects of primacy, recency, and modality (an auditory recall advantage) were obtained for both groups. The groups performed similarly when audiovisual stimuli were paired with a spoken response, but children with SLI had smaller recency effects together with an unusually poor recall when visually presented items were paired with a pointing response. Such results cannot be explained on the basis of an auditory or speech deficit per se, and suggest that children with SLI have difficulty either retaining or using phonological codes, or both, during tasks that require multiple mental operations. Capacity limitations, involving the rapid decay of phonological representations and/or performance limitations related to the use of less demanding and less effective coding and retrieval strategies, could have contributed to the working memory deficiencies in the children with SLI.     

Adult age differences in sensitivity to semantic structure of prose.

50 18–33 yr olds and 43 62–67 yr olds from low- and high-education populations heard narrative passages at different presentation rates and difficulty levels in 2 experiments. Immediately after listening to a tape-recorded version of each story, Ss orally recalled it. Results consistently demonstrate that younger Ss remembered more than older ones, but Ss from all groups favored the main ideas in their recalls. Also, Ss from all ages and educational levels were equally able to identify the important information in the stories. It is suggested that sensitivity to the semantic structure of prose is not a major component of adult age differences in discourse comprehension. It is further suggested that adult age differences observed on discourse comprehension tasks may reflect an age-related decline in processing capacity. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of isolated vowels as auditory stimuli in eliciting the verbal transformation effect.

Determined the effectiveness of single isolated vowels as auditory stimuli in eliciting perceptual illusory changes in ss, a phenomenon referred to by R. M. Warren (see pa, vol. 36:3gh49w) as the "verbal transformation effect." 3 vowels, /i/, /ae/, and /u/, were individually presented to a group of 24 19-24 yr. Old normal listeners in a single experimental session. Each vowel was repeatedly presented by means of headphones for a period of 5 min. Results indicate that single isolated vowels are capable of eliciting verbal transformations in normal listeners. However, the transformations reported often differed from those obtained in previous studies which used more phonetically complex auditory stimuli. The nature of the verbal transformations, average number of alternate forms perceived and transitions employed, and average number of repetitions of the stimuli prior to the onset of the ss' 1st verbal transformations are discussed. Comparisons with findings of previous investigations are provided. (french summary) (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)     

"Interactive use of lexical information in speech perception": Correction to Connine and Clifton.

Reports an error in "Interactive use of lexical information in speech perception" by Cynthia M. Connine and Charles Clifton (Journal of Experimental Psychology: Human Perception and Performance, 1987[May], Vol 13[2], 291-299). 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. (The following abstract of the original article appeared in record 1987-23984-001.) 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)     

Learning and use of logical symbols by deaf and hearing subjects.

16 11-17 yr. old deaf Ss were as able as hearing Ss matched on age, IQ, and socioeconomic background in learning and using logical concepts, and superior to hearing Ss matched on written language comprehension, IQ, and socioeconomic background in learning these concepts. Verbal language comprehension apparently does not possess an exclusive determining influence in learning and grasping the significance of these concepts. It seems justifiable that the ability to identify correspondences between logical symbolic expressions and their stimulus combinations, to verbalize accurately the rules of these correspondences, and to use learned symbols in new contexts constitute increasingly more difficult levels of conceptual behavior. Supplementary verbalization of rules leads to more successful transfer than learning the rules without correct verbal formulations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction between drug discriminative stimuli and exteroceptive, sensory signals.

Interactions between drug discriminative stimuli based on 5.6 and 10 mg/kg sodium pentobarbital (ip) and exteroceptive stimuli (visual and auditory) were studied in 27 male Sprague-Dawley rats in a T-maze. In 3 groups, visual stimuli (light vs dark) were differentially paired with drug stimuli; the 4th group discriminated combinations of tonal frequencies (1 kHz or 10 kHz) and the presence or absence of pentobarbital (10 mg/kg). In general, visual stimuli controlled choice behavior (left or right turn) to a greater extent than did the drug training stimuli, whereas the auditory stimuli exerted no apparent control over the pentobarbital stimulus in Group 4. Tests with higher doses (13.75 and 17.5 mg/kg) indicated augmented stimulus control by the drug dimension in 2 groups (Group 1, 10 mg/kg pentobarbital vs saline; Group 2, 5.6 mg/kg vs 10 mg/kg pentobarbital) but not in the 3rd group (5.6 mg/kg pentobarbital vs saline) in the "conflict" situation, in which the exteroceptive conditions signaled one response whereas the drug stimulus signaled the opposite response. Discrimination training with only one of the stimulus dimensions resulted in stimulus control in the following order: 10 mg/kg vs saline?>?5.6 mg/kg vs saline?>?1 kHz vs 10 kHz. This indicates that the auditory stimuli were of marginal significance. It is concluded drugs can compete with exteroceptive, visual stimuli for associative strength. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)