Binding “what” and “where” in auditory working memory: An asymmetrical association between sound identity and sound location

Contrasting results in visual and auditory working memory studies suggest that the mechanisms of association between location and identity of stimuli depend on the sensory modality of the input. In this auditory study, we tested whether the association of two features both encoded in the “what” stream is different from the association between a “what” and a “where” feature. In an old–new recognition task, blindfolded participants were presented with sequences of sounds varying in timbre, pitch and location. They were required to judge if either the timbre, pitch or location of a single-probe stimulus was identical or different to the timbre, pitch or location of one of the sounds of the previous sequence. Only variations in one of the three features were relevant for the task, whereas the other two features could vary, with task-irrelevant changes. Results showed that task-irrelevant variations in the “what” features (either timbre or pitch) caused an impaired recognition of sound location and in the other task-relevant “what” feature, whereas changes in sound location did not affect the recognition of either one of the “what” features. We conclude that the identity of sounds is incidentally processed even when not required by the task, whereas sound location is not maintained when task irrelevant.     

Congenital amusia: A short-term memory deficit for non-verbal,but not verbal sounds

Congenital amusia refers to a lifelong disorder of music processing and is linked to pitch-processing deficits. The present study investigated congenital amusics’ short-term memory for tones, musical timbres and words. Sequences of five events (tones, timbres or words) were presented in pairs and participants had to indicate whether the sequences were the same or different. The performance of congenital amusics confirmed a memory deficit for tone sequences, but showed normal performance for word sequences. For timbre sequences, amusics’ memory performance was impaired in comparison to matched controls. Overall timbre performance was found to be correlated with melodic contour processing (as assessed by the Montreal Battery of Evaluation of Amusia). The present findings show that amusics’ deficits extend to non-verbal sound material other than pitch, in this case timbre, while not affecting memory for verbal material. This is in line with previous suggestions about the domain-specificity of congenital amusia.     

Cognitive development, reading and prosodic skills in children with cochlear implants

This report summarizes some of the results of studies in our laboratory exploring the development of cognitive, reading and prosodic skills in children with cochlear implantation (CI). The children with CI performed at significantly lower levels than the hearing comparison group on the majority of cognitive tests, despite showing levels of nonverbal ability. The differences between children with CI and hearing children were most pronounced on tasks with relatively high phonological processing demands, but they were not limited to phonological processing. Impairment of receptive and productive prosody was also evident in children with CI. Despite these difficulties, 75% of the children with CI reached a level of reading skill comparable to that of hearing children. The results are discussed with respect to compensation strategies in reading.     

The role of the auditory brainstem in processing linguistically-relevant pitch patterns

Historically, the brainstem has been neglected as a part of the brain involved in language processing. We review recent evidence of language-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem. We argue that there is enhancing of linguistically-relevant pitch dimensions or features well before the auditory signal reaches the cerebral cortex. We propose that long-term experience with a tone language sharpens the tuning characteristics of neurons along the pitch axis with enhanced sensitivity to linguistically-relevant, rapidly changing sections of pitch contours. Though not specific to a speech context, experience-dependent brainstem mechanisms for pitch representation are clearly sensitive to particular aspects of pitch contours that native speakers of a tone language have been exposed to. Such experience-dependent effects on lower-level sensory processing are compatible with more integrated, hierarchically organized pathways to language and the brain.     

Functional heterogeneity of inferior frontal gyrus is shaped by linguistic experience

A crosslinguistic, positron emission tomography (PET) study was conducted to determine the influence of linguistic experience on the perception of segmental (consonants and vowels) and suprasegmental (tones) information. Chinese and English subjects (10 per group) were presented binaurally with lists consisting of five Chinese monosyllabic morphemes (speech) or low-pass-filtered versions of the same stimuli (nonspeech). The first and last items were targeted for comparison; the time interval between target tones was filled with irrelevant distractor tones. A speeded-response, selective attention paradigm required subjects to make discrimination judgments of the target items while ignoring intervening distractor tones. PET scans were acquired for five tasks presented twice: one passive listening to pitch (nonspeech) and four active (speech = consonant, vowel, and tone; nonspeech = pitch). Significant regional changes in blood flow were identified from comparisons of group-averaged images of active tasks relative to passive listening. Chinese subjects show increased activity in left premotor cortex, pars opercularis, and pars triangularis across the four tasks. English subjects, on the other hand, show increased activity in left inferior frontal gyrus regions only in the vowel task and in right inferior frontal gyrus regions in the pitch task. Findings suggest that functional circuits engaged in speech perception depend on linguistic experience. All linguistic information signaled by prosodic cues engages left-hemisphere mechanisms. Storage and executive processes of working memory that are implicated in phonological processing are mediated in discrete regions of the left frontal lobe.     

Vocal Features of Conversational Sarcasm: A Comparison of Methods

This study investigated vocal cues that differentiate sarcastic utterances from non-sarcastic utterances. Utterances were drawn from videotapes of participant interviews and arranged on a master tape for analysis. Utterances that were identified as sarcastic by speakers and recognized as sarcastic by listeners were randomly arranged with utterances identified and recognized as non-sarcastic by the same participants. Both sarcastic and non-sarcastic utterances were analyzed by two methods–acoustic analysis and perceptual coding. The acoustic analysis proved slightly more successful than the perceptual coding in discriminating between sarcastic and non-sarcastic utterances. The acoustic analysis indicated that fundamental frequency, frequency range, length of utterance, and total amount of sound significantly discriminated sarcastic from non-sarcastic utterances. The perceptual coding method revealed that pitch range, length of utterance, and total amount of sound significantly discriminated sarcastic from non-sarcastic utterances. Moderate correlations were found between the acoustic and perceptual variables.     

Guess who? Children use prosody to infer intended listeners

This study examined the relative influence of prosody and semantic content in children's inferences about intended listeners. Children (n = 72), who ranged in age from 5 to 10 years, heard greetings with prosody and content that was either infant or adult directed and chose the intended listener from amongst an infant or an adult. While content affected all children's choices, the effect of prosody was stronger (at least, for children aged 7–10 years). For conditions in which prosodic cues were suggestive of one listener, and content cues, another, children aged 7–10 years chose the listener according to prosody. In contrast, the youngest age group (5‐ to 6‐year‐olds) chose listeners at chance levels in these incongruent conditions. While prosodic cues were most influential in determining children's choices, their ratings of how certain they felt about their choices indicated that content nonetheless influenced their thinking about the intended listener. Results are the first to show the unique influence of prosody in children's thinking about appropriate speech styles. Findings add to work showing children's ability to use prosody to make inferences about speakers' communicative intentions.