Nonstutterers'' perceptions of stuttering and speech difficulty

Two versions of Woolf's (1967) Perception of Stuttering Inventory (PSI) were administered to nonstuttering college students in three experiments. In one (Woolf's published version) the word “stuttering” appeared and in another [a version developed by Daly, Oakes, Breen, and Mishler (1981)] “stuttering” was replaced by “speech difficulty.” Nonstutterers' scores on the PSI were found to be affected by knowledge of—or attention to—“stuttering” or “stutterers” as well as orientation toward speech or speech pathology. It was concluded that a total PSI score of 5 is presently a more defensible criterion of normality for stutterers than the more commonly used score of 10.     

Encoding and the rea for speech signals

A number of different possible explanations are distinguished for the findings on the right ear advantage (REA) for speech signals varied in their acoustic and phonetic properties. Two experiments are reported, using synthesized semivowels and vowels in monosyllable word frames. Both show REA. The detailed results of both experiments support the idea that a complicated “encoded” relationship between the acoustical stimulus and the response phoneme is a necessary condition for the REA, but that the encoding need only be signalled by an acoustical “trigger feature” in the stimulus; a task requiring a perceptual decoding is not necessary for REA to occur.     

Spontaneous speech generation

A speech generation task was performed by bilingual subjects whilst they received irrelevant messages in one ear. The irrelevant messages varied in content as well as in language. Although these messages appeared to have a significant influence on the rate of speech, this variation was not consistent with any of the three hypotheses suggested. A further speech generation experiment was then carried out in which subjects received as irrelevant auditory input, in one ear, either a prose passage or “emotional” words repeated over a period of 1 min. Although the rate of speech did not seem to be affected by the irrelevant input, a memory test for words spoken, as distinct from words heard seemed to indicate that the “emotional” words were significantly better recalled than the words from the prose passage. When a control experiment was performed with prose or repeated neutral words as auditory input, no such difference in recall was obtained. This result was seen as favouring Deutsch's model of the blocking of irrelevant speech.     

Single band amplitude envelope cues as an aid to speechreading

Amplitude envelopes derived from speech have been shown to facilitate speech-reading to varying degrees, depending on how the envelope signals were extracted and presented and on the amount of training given to the subjects. In this study, three parameters related to envelope extraction and presentation were examined using both easy and difficult sentence materials: (1) the bandwidth and centre frequency of the filtered speech signal used to obtain the envelope; (2) the bandwidth of the envelope signal determined by the lowpass filter cutoff frequency used to “smooth” the envelope fluctuations; and (3) the carrier signal used to convey the envelope cues. Results for normal hearing subjects following a brief visual and auditory-visual familiarization/training period showed that (1) the envelope derived from wideband speech does not provide the greatest benefit to speechreading when compared to envelopes derived from selected octave bands of speech; (2) as the bandwidth centred around the carrier frequency increased from 12.5 to 1600 Hz, auditory-visual (AV) performance obtained with difficult sentence materials improved, especially for envelopes derived from high-frequency speech energy; (3) envelope bandwidths below 25 Hz resulted in AV scores that were sometimes equal to or worse than speechreading alone; (4) for each filtering condition tested, there was at least one bandwidth and carrier condition that produced AV scores that were significantly greater than speech-reading alone; (5) low-frequency carriers were better than high-frequency or wideband carriers for envelopes derived from an octave band of speech centred at 500 Hz; and (6) low-frequency carriers were worse than high-frequency or wideband carriers for envelopes derived from an octave band centred at 3150 Hz. These results suggest that amplitude envelope cues can provide a substantial benefit to speechreading for both easy and difficult sentence materials, but that frequency transposition of these signals to regions remote from their “natural” spectral locations may result in reduced performance.     

Language as gesture

Language can be understood as an embodied system, expressible as gestures. Perception of these gestures depends on the “mirror system,” first discovered in monkeys, in which the same neural elements respond both when the animal makes a movement and when it perceives the same movement made by others. This system allows gestures to be understood in terms of how they are produced, as in the so-called motor theory of speech perception. I argue that human speech evolved from manual gestures, with vocal gestures being gradually incorporated into the mirror system in the course of hominin evolution. Speech may have become the dominant mode only with the emergence of Homo sapiens some 170,100 years ago, although language as a relatively complex syntactic system probably emerged over the past 2 million years, initially as a predominantly manual system. Despite the present-day dominance of speech, manual gestures accompany speech, and visuomanual forms of language persist in signed languages of the deaf, in handwriting, and even in such forms as texting.     

Perceptual grouping of speech components differing in fundamental frequency and onset-time

Are there general auditory grouping principles that allow the sounds of a single speaker to be grouped together before phonetic categorisation? Four experiments are reported on the use made of a common fundamental frequency or a common starting time in grouping formants together to form phonetic categories. The first experiment shows that the perception of a vowel category is unaffected by formants being excited at different fundamentals or starting at 100-ms intervals. The second and third experiments show no effect of a different fundamental on the combination of the timbres of pairs of formants presented either binaurally or dichotically to form diphthongs. Onset-time also has no effect with binaural presentation. The fourth experiment finds both an effect of grouping formants by a common fundaental using formant trajectories that do not overlap in frequency, and also an effect of onset-time. Neither a common fundamental nor common onset-time is either a necessary or a sufficient condition for formants to be grouped into a common speech category, although they can be shown to exert an influence. Both these variables exert a considerable influence on the number of sounds that subjects report hearing, even under conditions where they do not influence the reported speech category, indicating a dissociation between mechanisms concerned with “how many” sound sources there are, and those concerned with “what” a source consists of.     

On the division of attention: A disproof of the single channel hypothesis

In dichotic listening, subjects are apparently unable to attend simultaneously to two concurrent, auditory speech messages. However, in two experiments reported here, it is shown that people can attend to and repeat back continuous speech at the same time as taking in complex, unrelated visual scenes, or even while sight-reading piano music. In both cases performance with divided attention was very good, and in the case of sight-reading was as good as with undivided attention. There was little or no effect of the dual task on the accuracy of speech shadowing. These results are incompatible with the hypothesis that human attention is limited by the capacity of a general-purpose central processor in the nervous system. An alternative, “multi-channel”, hypothesis is outlined.     

Pedagogy of Play

“Pedagogy of play” focuses on the educational value of this field of experience, by claiming that play characterizes the two fundamental guidelines which are at the basis of education; the spontaneous and natural direction on the one side, and the intentional one on the other side. It is commonly assumed that pedagogy of play concerns only the latter of the two above-mentioned aspects of education, that is to say the design and management of playing experiences and materials with clear educational goals; instead, this discipline critically analyzes the whole playing experience, therefore trying to grasp its potentialities, its material conditions, and its overall meanings in the making of the subject. Moving from some considerations about the discovery of play as an emblematic index of the “discovery of childhood” at the beginning of Modern Age (Ariès, 1960), the first part of this essay underlines three aspects: the first concerns the investment on play as an educational device (from Locke to Montessori, up to Children’s Museums), pointing out the shift from the classic principle of ludendo docere to the modern ludendo discere. The second aspect focuses on the retrieval of the natural dimension of play, which finds in Rousseau its main source; the third takes into consideration toys and their identity both as pedagogical devices and as media. In the second part of the essay, the focus is on free play and its educational value, which is here interpreted especially as the first field of experience for children’s “political education”. The final remarks include some speculations the relationship between play and daily life, suggesting the idea that “life-long playing” could be defined as a meaningful aspect of long-life education.     

Burst cues, transition cues, and hemispheric specialization with real speech sounds

Subjects listening to dichotically presented real speech stop and fricative consonants, with and without transitions, showed larger laterality effects in the transition-less condition. In a second study, laterality effects for burst cues and transition cues were compared; using the stop consonants /b/ and /d/. Again, burst cues produced a larger laterality effect. These results are not compatible with a lateralized speech “decoder”, and are interpreted as favoring a Semmes (1968) model of hemispheric differences, differential processing.     

Disruption of memory for lip-read lists by irrelevant speech: Further support for the changing state hypothesis

Two experiments critically re-examine the finding of Campbell and Dodd (1984, Experiment 2), which suggests that irrelevant speech disrupts the encoding of visual material for serial recall. Support is sought for the competing view that the effect of irrelevant speech is on storage by comparing the effect of a range of acoustic conditions on memory for graphic and lip-read lists. Initially, serial short-term recall of visually presented lists was examined with irrelevant speech that was both asynchronous with the visually presented items and of varied speech content (Experiment 1a). In this experiment substantial impairments in recall of both graphic and lip-read lists were found. However, with unvarying asynchronous speech (Experiment 1b) the effect of speech was small and non-significant. Experiment 2 examined the effect of changing state and of synchrony of speech with lip movements. When conditions of synchronous and asynchronous unvarying speech were contrasted, no significant effect of synchrony or irrelevant speech was found (Experiment 2a and 2c). In contrast, when the speech was varying in content, a strong effect of irrelevant speech was found; moreover, the effect was roughly the same for synchronous and asynchronous materials (Experiment 2b). The contrast in outcome with varying and unvarying speech provides strong support for the “changing state” model of the irrelevant speech effect. Coupled with the absence of an effect of synchrony in Experiment 2, these experiments reinforce the view that disruption by irrelevant speech occurs in memory, not at encoding.     

Assertive training: An adjunct to fluency shaping

“Assertive Training” has been utilized as an adjunct therapy in a six week residential program at Walter Reed Army Medical Center. The speech pathology staff in conjunction with the psychology staff determined that a persistent problem with long term success after patients were dismissed from therapy was largely due to a “behavioral deficit” in their interpersonal verbal confrontations. The anxiety resulting from such communication failure simply chips away at the self confidence needed to maintain a working level of fluency, resulting in a “snowballing” effect back to dysfluency.

Thus, the goals and procedures of assertive training for stutterers are discussed as a means to shape more effective skills in relating to others in difficult situations. Pre, post and six month follow-up data are presented.     

Contribution of the speech musculature to apparent human EEG asymmetries prior to vocalization

Vocalizations are preceded by slow EEG waves over inferior frontal scalp regions, but some controversy exists as to whether these slow potentials are left-lateralized as a function of speech. In this study both speech and non-speech vocalizations were studied, under conditions of repetitive and variable production. Averaged responses over the speech musculature, including the temporalis, masseter, orbicularis oris, and mylohyoid muscles, as well as the eyes and tongue, were calculated simultaneously with scalp EEG averages. The responses of the temporalis and masseter muscles, as well as that of the tongue, were correlated with EEG sites at specific latencies prior to speech, suggesting that no part of the inferior frontal EEG record was free from myogenic confounds. In addition, all significant EEG differences between speech and non-speech conditions were subsequently eliminated by covariance analysis, using selected muscle channels as covariates. Previous reports of asymmetrical “speech potentials” in the EEG probably reflected a combination of several myogenic confounds.     

Left and Right Hemifield Advantages of Fusions and Combinations in Audiovisual Speech Perception

If a place-of-articulation contrast is created between the auditory and the visual component syllables of videotaped speech, frequently the syllable that listeners report they have heard differs phonetically from the auditory component. These “McGurk effects”, as they have come to be called, show that speech perception may involve some kind of intermodal process. There are two classes of these phenomena: fusions and combinations. Perception of the syllable /da/ when auditory /ba/ and visual /ga/ are presented provides a clear example of the former, and perception of the string /bga/ after presentation of auditory /ga/ and visual /ba/ an unambiguous instance of the latter. Besides perceptual fusions and combinations, hearing visually presented component syllables also shows an influence of vision on audition. It is argued that these “visual” responses arise from basically the same underlying processes that yield fusions and combinations, respectively. In the present study, the visual component of audiovisually incongruous CV-syllables was presented in the left and the right visual hemifield, respectively. Audiovisual fusion responses showed a left hemifield advantage, and audiovisual combination responses a right hemifield advantage. This finding suggests that the process of audiovisual integration differs between audiovisual fusions and combinations and, furthermore, that the two cerebral hemispheres contribute differentially to the two classes of response.     

The contribution of “cool” and “hot” components of decision-making in adolescence: Implications for developmental psychopathology

Impairments in either “cool” or “hot” processes may represent two pathways to deficient decision-making. Whereas cool processes are associated with cognitive and rational decisions, hot processes are associated with emotional, affective, and visceral processes. In this study, 168 boys were administered a card-playing task at ages 13 and 14 years to assess response perseveration. This task was designed to initially reward playing and gradually associate playing with punishment. Measures of subjective ordering (cool processes) and neuroticism (hot processes) at age 13 years were used to examine how these individual characteristics relate to perseveration over time. A decrease in perseveration from age 13 to 14 was associated with cool processes whereas hot processes were associated with response perseveration only over time. A complementary but simultaneous assessment of cool and hot processes, such as neuropsychological and personality tests, could facilitate treatment planning of children with behavioral problems.     

I: Effect of delayed auditory feedback on speech and keytapping

The effects of delayed auditory feedback (DAF) on the performance of simple speech and keytapping tasks were compared. In the first experiment, each of the fourteen young adult subjects was asked to repeat the speech sound “b” in groups of three sounds. The subject heard his undelayed speech sounds through earphones. Under the delay condition, the speech sounds were delayed 244 millisec. before being returned to the subject's earphones. In the second experiment, each of the same subjects was asked to tap on a key in groups of three taps. The subjects heard an undelayed click through earphones each time they tapped on the key. Under the delay condition, the clicks were delayed 244 millisec. before being returned to the earphones. Graphic recordings were made of the time and intensity characteristics of tapping under both conditions.

The changes which occurred in speech and keytapping under DAF were qualitatively the same and consisted of increases in intensity and unit-to-unit time of both taps and speech sounds. When performing under DAF, the subjects also exhibited a tendency to repeat more sounds or to tap more times than had been requested. The percentage of change in intensity and time characteristics for speech and keytapping performances which occurred under DAF were not significantly different for the two motor systems. The amount of change in speech performance under DAF did not correlate significantly with the amount of change in keytapping performance.     

A study of alpha hemispheric asymmetries for verbal and nonverbal stimuli in males and females

The alpha hemispheric asymmetries of males and females were examined with electroencephalographic (EEG) techniques during exposure to connected speech and nonlinguistic stimuli. The subject selection controlled for familial handedness and each subject was administered the Block Design and Vocabulary Subtests of the WAIS as a general measure of “visual-spatial” and “verbal” ability. The results showed that there was less alpha in the right hemisphere for nonverbal tasks and less alpha in the left hemisphere for verbal tasks. The females showed significantly more “lateralization” during the tasks as compared to the males. The results are discussed in terms of processing differences and the possible effects of subject variables, stimulus mode, stimulus presentation, and task requirements on neurolinguistic research results.     

Evaluation of the efficacy of a stutter modification program with particular reference to two new measures of secondary behaviors and control of stuttering

This study aimed to assess the changes in speech behaviors and attitudes of a group of stutterers who attended an intensive stutter modification program, using measures specifically designed to reflect the aims of the program. These included a measure of “clean” stuttering to quantify overt secondary behaviors and a quantitative measure of speech control to assess changes in control over stuttering moments using the taught handling techniques. High interjudge and intrajudge agreement was obtained on the two new speech measures. In addition, the program’s own Attitude Scale was used to assess changes in attitudes toward communication. The five subjects were assessed immediately after and 2 years after the program. Each subject was analyzed as a single case study, and there was great individual variation in response to therapy. The general trend was a decline in the maintenance of speech behaviors, with good maintenance of attitude gains 2 years postworkshop. The poorest maintenance was linked to lack of attendance at refresher therapy and initial severity of stuttering. The two new measures used to evaluate change in clean stuttering and control may be useful tools in the assessment protocol of other Stutter Modification programs.     

Perception and awareness in phonological processing: the case of the phoneme

The necessity of a “levels-of-processing” approach in the study of mental representations is illustrated by the work on the psychological reality of the phoneme. On the basis of both experimental studies of human behavior and functional imaging data, it is argued that there are unconscious representations of phonemes in addition to conscious ones. These two sets of mental representations are functionally distinct: the former intervene in speech perception and (presumably) production; the latter are developed in the context of learning alphabetic literacy for both reading and writing purposes. Moreover, among phonological units and properties, phonemes may be the only ones to present a neural dissociation at the macro-anatomic level. Finally, it is argued that even if the representations used in speech perception and those used in assembling and in conscious operations are distinct, they may entertain dependency relations.     

The problem of relapse in stuttering: Some thoughts on what might cause it and how to deal with it

Bloodstein recently wrote that “the most vital part of science is not accurate measurement or the insistence on empiricism. It is an attitude of inquiry into the how and why of things” [Bloodstein, O. Foreword. In: Maintenance of Fluency (E. Boberg ed.). New York: Elsevier, 1981, p. vii]. In the paper below, I present some unsubstantiated and no doubt controversial thoughts on the how and why of relapse in stuttering. The overall thrust of these thoughts is that stutterers have different propensities to stutter because of the inherent variability in their speech production systems. For this reason, for therapy to have long-range success, stutterers must learn to accept and deal with the inherent variability in their speech production mechanisms.     

Part of speech and phonological form implied in written-word comprehension: Evidence from homograph disambiguation by normal and aphasic subjects

A sentence construction experiment examining the effect of part of speech and phonological form in written-word comprehension is reported. Normal and aphasic subjects had to write sentences incorporating a given word pair, one word was a homograph (e.g., “bank”) whose meaning was context-biased by the other (e.g., “money”/“river”). The effect of three psycholinguistic factors on subjects' performance was questioned: (i) The relative frequency of one meaning of the homograph as compared to the other meaning; (ii) The lexical/syntactic ambiguity (“ball”/“can”); (iii) The same/different phonological forms of the two meanings (“fair”/“bass”). The results are discussed in the framework of a model in which multiple special-purpose procedures are involved in normal processing, some of them being differentially impaired by brain disease in Broca's and Wernicke's aphasics.