Gerald M. Siegel

Inhibiting the Lombard effect

The Lombard effect is the tendency to increase ones vocal intensity in noise. The present study reports three experiments that test the robustness of the Lombard effect when speakers are given instructions and training with visual feedback to help suppress it. The Lombard effect was found to be extremely stable and robust. Instructions alone had little influence on the response to the noise among untrained speakers. When visual feedback correlated with vocal intensity was presented, however, subjects could inhibit the Lombard response. Furthermore, the inhibition remained after the visual feedback was removed. The data are interpreted as indicating that the Lombard response is largely automatic and not ordinarily under volitional control. When subjects do learn to suppress the effect, they seem to do so by changing overall vocal level rather than their specific response to the noise.

Auditory feedback in the regulation of voice

Adult speakers participated in a spontaneous speech task in which the intensity of their auditory feedback through earphones was systematically manipulated over a 20‐dB‐SPL range. In Experiment I, Ss showed a statistically significant but slight tendency to decrease their vocal intensity as sidetone was amplified. The effect was greatest when subjects were instructed to attend to their sidetone and to compensate for any changes in loudness. In Experiment II, the same procedures were repeated except that 80‐dB‐SPL noise was added in the earphones. Addition of the noise resulted in considerably enhanced sidetone‐amplification effects, even when Ss were instructed to keep their vocal level constant. In Experiment III, several levels of noise (0, 60, 70, 80 dB SPL) were used and it was noted that the greater the noise, the more substantial were the sidetone‐amplification effects. In Experiment IV, subjects were instructed to talk either louder or softer than usual, with and without noise. The data from this l...

Variations in Normal Speech Disfluencies

College adults were asked to speak in each of three situations. All 40 subjects started in an Alone situation in which they simply talked spontaneously about any topic while sitting alone in a room. They then participated in a situation in which they were asked to speak alone in front of a TV camera and lights, or as if to an audience (Audience-TV situation). Finally, the experimenter entered the room and engaged the subject in casual Conversation for the final situation. Each situation was 12 minutes and was tape recorded. After the last session, the subjects filled out a brief questionnaire in which they rated each situation according to their judgment of the need to speak carefully and of their estimated disfluency in the situation. The most significant finding is that subjects were most disfluent in those situations they rated as least important. Contrary to usual observations, the greatest frequency of disfluencies occurred in the Conversation rather than the Audience-TV situation. It appeared that as subjects became more concerned about their speech, they monitored it more carefully and thus became more fluent.

Demands and capacities or demands and performance

Abstract The Demands and Capacities Model of stuttering purportedly provides a framework for obtaining information concerning a childs capacities for fluency and the demands placed on the child by the environment and for integrating that information in devising individual therapy plans. The current paper analyzes the model, with specific attention to the status of the “capacities” component. It is suggested that the model is more accurately characterized as a Demands and Performance rather than a Demands and Capacity Model because capacities are not actually addressed.

Reliability of sidetone amplification effect in vocal intensity.

When the auditory feedback of a speakers own voice is amplified the speaker reasonably tends to lower his voice. The reliability of this so called sidetone amplification effect was investigated in two experiments. In the first experiment feedback was modulated gradually during a session. In the second experiment the sidetone amplification effect was assessed over five successive days of testing. In both experiments the sidetone effect was very stable despite rather different eliciting conditions.

Auditory feedback and speech development.

Publisher Summary This chapter evaluates the role of feedback, particularly auditory feedback, in the development of speech in children. In the recent enthusiasm for exploring rule-governed bases of linguistic competence, the fact that speech is a highly coordinated motor skill has been almost ignored. Competence theories have ruled the imagination of researchers whereas performance data have been grudgingly accepted as the imperfect source from which competence theories are derived. As important as linguistic considerations are, they inevitably take form through an expressive system such as speech, writing, or signing, and such a system could scarcely function without the contribution of feedback, at least during certain stages of development. Under normal circumstances, speech clearly is multiply determined. Speakers acquire the language to which they have been exposed in the presence of different kinds of listeners and in a variety of social and physical situations. Although it is a motor skill, speech is the expression of linguistic codes and communication needs. Speakers talk louder in noise and also to impress a listener with their determination. Choice of words, speech rate, and inflectional pattern are all multiply determined, reflecting the contributions of social and physical variables, as well as the physiological constraints of the speech system. The relationship between forms of feedback and the various parameters of speech production are well worth exploring in future research. The area is an exciting one, as it pertains both to normal and deviant speech development.

Feedback and Motor Control in Stuttering

For speech production to proceed smoothly, the timing and coordination of a variety of complex movement patterns must be programmed and carried out in a precise fashion. During the moment of stuttering, this process is disrupted, and the stutterer may appear to be struggling in the grip of an uncontrollable spasm or seizure. For this and other reasons, early theorists attempted to identify some underlying physical abnormality as the root cause of stuttering. The earliest programmatic research in stuttering involved comparisons of stutterers and nonstutterers on a great variety of physiological, motor, and perceptual variables. After many years of such research, the accumulated evidence was at best suggestive, and no constellation of physiological variables emerged that could unequivocally be identified with either the person who stutters or the moment of stuttering (Bloodstein, 1975).

The effect of task variables on speech during oral anesthesia

A normal, adult female performed a variety of speech tasks before and after a series of nerve-block injections that anesthetized the oral cavity. The tasks included diadokokinesis, imitation of unfamiliar Swedish phonemes, production of one-, two-, three-, and four-syllable words, and of two prose passages. Four experienced judges scored misarticulations. Intelligibility was determined in a series of listening studies involving college students. The highest percentage of misarticulations occurred on the single-syllable word list and the most complex prose passage. There were virtually no misarticulations on the two- or three-syllable words. Intelligibility tended to covary with articulation, but the specific nature of the relationship depended on the particular speech task. A misarticulation was especially likely to result in unintelligibility on the most difficult passage, although not all unintelligible words on that passage were attributable to phonemic errors.

The effects of feedback filtering on speaker intelligibility.

Subjects read intelligibility tests while hearing their voices low- or high-pass filtered. The tests were presented to listeners to assess speaker intelligibility. Feedback filtering had a variable effect on intelligibility. When speakers were permitted to increase their intensities in low-pass filtering conditions, their intelligibility also increased. Intelligibility did not increase when intensity was controlled. These results do not support the hypothesis that speakers modulate their voices in order to maintain intelligible communication with a presumed listener. IT is suggested instead that speakers alter their intensities in order to regulate the loudness of their voices in their own ears.

Studies in speech fluency

Abstract A series of experiments involving speech dysfluencies of normal, adult speakers is presented and evaluated in light of earlier work on the conditioning of dysfluencies in a punishment paradigm. The data suggest that the dysfluencies of normal speakers can be systematically manipulated in a variety of ways, ranging from specific punishment procedures to changes in general situational variables. When the variety of studies is reviewed in which dysfluencies have been altered in experimental situations, it appears that three major variables emerge: the speakers perception and evaluation of the situation in which he is performing; the speakers history of experiences with nonfluencies in earlier, similar situations; the nature and arrangement of the contingent stimulus. Some comparisons between stutterers and normal speakers are tentatively advanced in a final section.