Hierarchical coding in speech timing

The analysis of syllable and pause durations in speech production can provide information about the properties of a speaker's grammatical code. The present study was conducted to reveal aspects of this code by analyzing syllable and pause durations in structurally ambiguous sentences. In Experiments 1–6, acoustical measurements were made for a key syllabic segment and a following pause for 10 or more speakers. Each of six structural ambiguities, previously unrelated, involved a grammatical relation between the constituent following the pause and one of two possible constituents preceding the pause. The results showed lengthening of the syllabic segments and pauses for the reading in which the constituent following the pause was hierarchically dominated by the higher of the two possible preceding constituents in a syntactic representation. The effects were also observed, to a lesser extent, when the structurally ambiguous sentences were embedded in disambiguating paragraph contexts (Experiment 7). The results show that a single hierarchical principle can provide a unified account of speech timing effects for a number of otherwise unrelated ambiguities. This principle is superior to a linear alternative and provides specific inferences about hierarchical relations among syntactic constituents in speech coding.     

Significance of pauses for speech perception

Pauses can be used to facilitate certain operations involved in the production and in the perception of speech. In the case of speech perception, pauses have been found to improve the accuracy of detection and the recall of lists of digits and letters. The aim of the present experiments was to examine the effects of pause time on the perception of sentences. In experiment I, a semantic categorization task was used and in experiment II a sentence recall task. The results indicated that in sentences containing pauses between clauses, words were categorized more rapidly (experiment I) and propositions were recalled more accurately (experiment II) than in sentences containing pauses, within the clause. The results are interpreted in the context of existing models of speech processing, and the significane of pause time for cognitive activity is discussed.     

The patterns of silence: Performance structures in sentence production

The pauses produced by speakers while reading familiar material were used to obtain hierarchical sentence structures. Identical structures were obtained from parsing, indicating that the performance structures of sentences are not task specific. The linguistic surface structure of a sentence is a good predictor of the pause durations. However, speakers also revealed a tendency to place pauses between segments of equal length. A simple cyclical model combining, for each pause location, an index of linguistic complexity and a measure of the distance to the midpoint of the segment, accounts for 72% of the pause time variance as opposed to 56% for the linguistic index alone. The generality of the model is shown by its good prediction of the pause durations obtained in unrelated studies in English and American Sign Language.     

Vocal congruence in mother-infant play

Turn-taking is the fundamental temporal structure of adult dialogue. This structure defines two types of joint silence: intrapersonal pause (silence bounded by the vocalizations of a single speaker) and switching pause (silence bounded by the vocalizations of different speakers). Switching pauses mark the boundaries of the turn exchange. In adult conversation the mean durations of both types of pause are characteristically matched between partners. This matching, termed vocal congruence, occurs developmentally earlier in the case of switching pauses. We hypothesized and confirmed that mothers and infants match switching pauses but not intrapersonal pauses at 4 months, even though the infants' vocalizations are prelinguistic. Second, since there are known affective correlates of vocal congruence in adult conversation, we hypothesized a similar affective correlate for mother-infant vocal congruence. We found, for the intrapersonal pause only, that the degree of matching within a dyad correlated with infant affective engagement. We conclude, from switching pause congruence, that a turntaking dialogic structure is being regulated in the mother-infant pair at 4 months in the same way as seen in adult conversation. Thus, both the temporal structure of adult dialogue and its affective correlate are prelinguistic.Supported in part by NIMH grant No. 41675.     

TEMPORAL CONTROL ON INTERVAL SCHEDULES: WHAT DETERMINES THE POSTREINFORCEMENT PAUSE?

On fixed-interval or response-initiated delay schedules of reinforcement, the average pause following food presentation is proportional to the interfood interval. Moreover, when a number of intervals of different durations occur in a programmed cyclic series, postreinforcement pauses track the changes in interval value. What controls the duration of postreinforcement pauses under these conditions? Staddon, Wynne, and Higa (1991), in their linear waiting model, propose control by the preceding interfood interval. Another possibility is that delay to reinforcement, signaled by a key peck and/or stimulus change, determines the subsequent pause. The experiments reported here examined the role of these two possible time markers by studying the performance of pigeons under a chained cyclic fixed-interval procedure. The data support the linear waiting model, but suggest that more than the immediately preceding interfood interval plays a role in temporal control.     

Adjusting fixed-ratio schedules in the squirrel monkey

On an adjusting schedule of reinforcement, a parameter of the schedule is varied as a function of some characteristic of the animal's performance. In Experiment I, the fixed-ratio response requirement was varied as a function of the time that elapsed before the animal started responding in each fixed-ratio (initial pause). When initial pauses were shorter than a specified duration, the response requirement was increased; when they were longer than the specified duration, the response requirement was decreased. Specified durations of 1, 2, 4, 8, and 15 min were studied. The average response requirement maintained by each monkey was directly related to the length of the specified duration of initial pause. In Experiment II, the fixed-ratio response requirement was constant, but reinforcement occurred only when the initial pause was longer than a specified duration. The average durations of initial pauses were directly related to the length of the specified duration and to the response requirement. Meprobamate consistently decreased the average durations of initial pauses.     

An automatic analysis method of utterance and pause lengths and frequencies

Automatic analysis of the lengths and frequencies of utterance and pauses is highly desirable in the study of large amounts of speech produced by pathologic speakers and of interactive speech such as that between mother and child, clinician and client, and teacher and student. This paper describes a microcomputer-based analysis method of utterance and pause lengths and frequencies in connected speech. The instrumentation consists of a rectifier-smoother circuit, an analog-to-digital convertor and an Apple microcomputer. The printouts list utterances and pauses (in milliseconds) in the order of occurrence, and means and standard deviations of the utterances and pauses. The program and the results of reliability and validity tests of this method are described.     

An experimental investigation of the modifiability of the temporal structure of spontaneous speech

This study attempted to test the hypothesis that the temporal structure of spontaneous speech is modifiable by reinforcing and punishing pauses, of a certain duration, in an operant conditioning situation. Pause rate was significantly affected by these contingencies: moreover, rate of change was rapid, indicating a prepared association between pausing and such contingencies. This study also attempted to test the hypothesis that there is a class of noncognitive pauses in monologue by punishing UPs to determine if UPs can be eliminated without affecting speech content. Although this manipulation did lead to a decline in pause rate, a significant increase in the amount of filled hesitation, particularly in repetition, resulted. This suggests that the overall amount of hesitation is fixed by the cognitive demands of the task but that a speaker is able to adapt to different interactional contexts by varying the category of hesitation used for cognitive planning.     

Pause loci in stuttered and normal speech

The mainstream of research comparing types of disfluency in stuttered and normal speech has typically omitted consideration of pause. In contrast, psycholinguisticresearch addressed to disfluency in normal speech alone has revealed the salience of pause in the study of fluency/disfluency. The research reported here, which focused on the antecedents and sequelae of filled pauses, revealed substantial differences in pattern of pause occurrence between stuttered and normal speech samples obtained from 20 matched subjects. The results are discussed in reference to relevant findings from the research on pause in normal speech.     

Conversational time patterns and mutual influence in parent-child interactions: A time series approach

Mutual influencing processes are assumed to be the basic building blocks in establishing parentchild bonding and in influencing cognitive and language behavior. A study by Jasnow and Feldstein (1986) revealed that, within the temporal domain of speech, preverbal (9-month-old) infants and their mothers exhibit a pattern of mutual influence (attunement) in their average durations of switching pauses. The general purpose of this research was to extend those findings to children with higher verbal functioning. In addition, parent and child genders, nature of the interaction, and specific aspects of parents' personalities, expressiveness, and instrumentality were considered. Each parent interacted with their 4-or 5-year-old son or daughter in each of two conversations—unstructured (social conversation) and structured (task activity). Conversations were processed by an automated computer system yielding objective measure of turns, vocalizations, pauses, and switching-pause durations. To examine interspeaker influence or attunement of temporal speech patterns, influence coefficients were computer for each speaker on a turn-by-turn basis using time series regression. Analysis of these coefficients revealed that: (1) Mutual influence is most evident with switching-pause duration. (2) Structure in the conversation (as defined by the task or parental instrumentality) seems to facilitate attunement for vocalization and switching pause duration. (3) Attunement with girls seems to occur equally well with both parents, while boys exhibit a style of temporal patterning influence which suggests greater identification with the father. (4) Expressiveness seems to facilitate attunement to the child's switching-pause duration.     

Think before you speak: pauses, memory search, and trace redintegration processes in verbal memory span

Immediate memory span and speed of memory search were assessed for words and nonwords of short and long spoken duration. Memory span was substantially greater for words than for nonwords and for short than for long items, though speed of memory search was unaffected by either length or lexicality. An analysis of the temporal pattern of responses in the memory span task indicated that inter-item pauses were longer between nonwords than words but that these pause durations were unaffected by item length. A model of verbal short-term memory span is described in which trace selection from a short-term store and the redintegration (restoration) of degraded phonological traces both occur in the pauses between saying successive items. Both trace selection and trace redintegration appear to play important roles in accounting for individual differences in memory span.     

Acoustic correlates of subjective pauses

This study investigates the perception of subjective pauses, i.e., pauses that do not correspond to silent pauses. Experiment I used stimuli which were excerpts from spontaneous speech which were presented in two versions: spectrally normal and spectrally inverted. Experiment II used stimuli which were generated by first cross-splicing the two halves of two sentences; they were further manipulated for fundamental frequency, intensity, or duration of the vowel just preceding the splice point. The task in both experiments was to press a button when a speech interruption was heard. The purpose of the experiments was to identify the grammatical and acoustic correlates of the subjective pauses thus reported. The results of Experiment I show, for the inverted speech condition, but not for the normal speech condition, an increase in pause reports as the duration of the prepausal vowel increased. The results of Experiment II show an increase in pause reports with increasing vowel duration. The implications of increased prepausal duration functioning as a pause signal are discussed.     

Detecting silent pauses in speech: a new tool for measuring on-line lexical and semantic processing

In this study, we introduce pause detection (PD) as a new tool for studying the on-line integration of lexical and semantic information during speech comprehension. When listeners were asked to detect 200-ms pauses inserted into the last words of spoken sentences, their detection latencies were influenced by the lexical-semantic information provided by the sentences. Listeners took longer to detect a pause when it was inserted within a word that had multiple potential endings, rather than a unique ending, in the context of the sentence. An event-related potential (ERP) variant of the PD procedure revealed brain correlates of pauses as early as 101 to 125 ms following pause onset and patterns of lexical-semantic integration that mirrored those obtained with PD within 160 ms of pause onset. Thus, both the behavioral and the electrophysiological responses to pauses suggest that lexical and semantic processes are highly interactive and that their integration occurs rapidly during speech comprehension.     

Infant cry as a graded signal: Experimental modifications of durations of pauses and expiratory sounds alter mothers' perceptions

The purpose of this study was to examine experimentally the effects of the temporal structure of infant crying on mothers' perceptions. Eighteen mothers of young infants rated variations of a 10-sec cry in which durations of all expiratory sounds and pauses were digitally lengthened and shortened by 50%. Results showed a general monotonic effect in which cries with increasingly shorter pauses were perceived to be more arousing, aversive, informative, and rough. Similarly, cries with short expirations were perceived to be more rhythmic and rough than cries with long expirations. The strength of the monotonic effect for pause duration on ratings of urgency interacted with the duration of expiratory sounds such that the combination of short pauses and short expirations created the greatest perceived urgency. This study replicates and extends previous findings which show that gradations in acoustic features of crying are associated with gradations in the intensity of adults' perceptions.     

Pauses in elementary school children's verbatim and gist free recall of a story

The aim of the research was to explore the function of pauses in children's oral verbatim and gist-based free recall, assuming that pauses indicate cognitive processing. The main question guiding this research was whether verbatim and gist recall constituted two different ways of cognitive processing associated with different time patterns of speech. Elementary school children (n = 180) between the ages of 8 and 10 years heard a story and were then instructed to either retell the story verbatim or retell its gist. They orally recalled the story for the first time immediately after hearing the story and again 1 week later. The results confirmed the main hypothesis of independence of verbatim and gist traces in that mean pause lengths were longer when verbatim retrieval was asked for as compared to gist retrieval. High correct gist recall was characterized by more and shorter pauses, indicating fluent retrieval.     

A study of timing in a manual and a spoken language: American sign language and English

A comparative analysis of the time variables in the production of speech and sign reveals that signers modify their global physical rate primarily by altering the time they spend articulating, whereas speakers do so by changing the time they spend pausing. When signers increase or decrease their pause time, however little they do so, they alter the number and the length of the pauses equally, whereas speakers primarily alter the number of pauses and leave their pause durations relatively constant. An analysis of the durations of signs reveals that signs are longer at the end of sentences than within sentences and that the first occurrence of a sign is longer than the second when syntactic location is controlled (both these findings have already been reported for spoken language). The inherent duration of a sign can be accounted for almost totally by the movement characteristic; handshape, location, and number of hands in a sign are of little importance. Finally, signers retain their regular quiet-breathing respiratory pattern across signing rates and inhale at locations independent of syntactic importance. In this they are quite unlike speakers, who breathe at syntactic breaks.This research was supported in part by Grant R03 MH 28133, Department of Health, Education, and Welfare.     

Evaluation of eye movement variables of Chinese and American readers

Eye movements were recorded while competent readers of English and Chinese read in their respective languages. There were no important differences in oculometric patterns of fixation pause durations for Chinese and American readers, suggesting that cognitive aspects of reading are more important than perceptual ones in determining eye movement patterns and fixation pauses of competent readers. An analysis of undershoot saccades associated with return of the eyes from the end of one line to the beginning of the next line suggests that these occur more frequently during reading than during the performance of similar eye movements that are more perceptually determined, however, the amount of undershoot does not discriminate between readers of alphabetic and logographic texts.     

Is Speech Temporally Segmented? Comparison with Temporal Segmentation in Behavior

Phrase durations in spoken German and Korean were examined for temporal segmentation like that in behavior. Lines of poetry, which may be regarded as semantic units equivalent to action units in behavior, were found to be temporally segmented but, unlike behavior, there is a significant effect of language/culture on segment length. The lengths of the pauses made between lines while reading poetry were used to define possible semantic segments in reading prose, retelling a story, free speech, and telephone messages. No temporal segmentation was found, each situation resulting in a different distribution of phrase durations. These results are discussed in terms of a possible evolution of language from the motor system.     

Vocalization and pauses in fast-paced reading

Previous research (Breznitz, 1987a) indicated that prompting first-graders to read faster than usual increases their comprehension. The present study was conducted to clarify which of the speech elements that comprise reading time is affected when reading pace is accelerated. First-graders (N = 76) read aloud three parallel forms of a comprehension test, at self- and fast-paced rates consecutively, followed by a second self-paced reading. Vocalization time, pause time, pause frequency, and the average length of vocalizations and pauses were determined with an automatic vocal transaction analyzer. During fast-paced reading, children made fewer and shorter pauses, vocalized at a faster rate, and tended to speak in longer units. The speech characteristics indicative of fast-paced reading were significantly correlated with reading comprehension, even during self-paced reading, and can serve as indicators of effective reading.