Transfer of training of a new linguistic contrast in voicing

The present study examined the plasticity of the human perceptual system by means of laboratory training procedures designed to modify the perception of the voicing dimension in synthetic speech stimuli. Although the results of earlier laboratory training studies have been ambiguous, recently Pisoni, Aslin, Perey, and Hennessy (1982) have succeeded in altering the perception of labial stop consonants from a two-way contrast in voicing to a three-way contrast. The present study extended these initial results by demonstrating that experience gained from discrimination training on one place of articulation (e.g., labial) can be transferred to another place of articulation (e.g., alveolar) without any additional training on the specific test stimuli. Quantitative analyses of the identification functions showed that the new perceptual categories were stable and displayed well-defined labeling boundaries between categories. Taken together with the earlier findings, these results imply a greater degree of plasticity in the adult speech processing system than has generally been acknowledged in past studies.     

Acquiring conjunctive concepts: When and why does feature frequency affect feature identification?

According to frequency theories of concept attainment, acquisition of rule-governed concepts depends on discriminating relevant from irrelevant stimulus features on the basis of their respective frequencies of occurrence. Depending on the theorist, the critical frequency counts may be based on occurrence in all stimuli or on occurrence in positive instances only. Experiment 1 held frequency in positive instances constant and varied the frequency of irrelevant features in the negative category. High frequency was associated with impaired performance, but only when concept problems started with a negative instance. Experiment 2 demonstrated that some previous findings in the literature that were thought to support frequency theory also depended on problems starting with a negative instance. These findings are not easily reconciled with existing frequency theories. We attribute our results to high intercategory similarity, which is a correlate of high frequency of irrelevant features. In the context of a hypothesis-testing theory, we propose that a negative start stimulus proactively interferes with memory for information in the initial positive instance and that the extent of the interference depends on how similar negative instances are to positive instances.     

Lesions of the basal ganglia, thalamus, and deep white matter: Differential effects on language functions

Forty-five patients with unilateral demarcated vascular lesions in the basal ganglia, the thalamus and the deep white matter were investigated with an "aphasia battery." Patients with basal ganglia lesions performed worse than both other groups in tests of articulation, syntax, and lexical functions. The deficit of patients with basal ganglia lesions on all expressive language modalities was lateralized to the left hemisphere. Patients with left thalamic lesions showed impairments of speech fluency and in the Token Test. Patients with white matter lesions alone showed no effect of laterality in tests of language functions. The results are discussed on the basis of a recent theory of the participation of the deep nuclei in language processing.     

Voice onset time production and perception in apraxic subjects

This study explored the relationship between the perception and production of voice onset time (VOT) in apraxic subjects. Spectrograms of the words, “bees” and “peas” spoken by apraxic subjects were acoustically analyzed to obtain a measure of VOT. The subjects also identified the initial cognate (“b” or “p”) from synthetically generated speech spanning a voiced to voiceless time continuum. The results suggest that apraxic subjects have production as well as perceptual errors in the voicing feature but no significant relationship was found between the two measures.     

An awareness approach to the covert symptoms of stuttering

Speech-language clinicians working with the confirmed stuttering client are often faced with the clinical management of the covert symptoms of stuttering in addition to the more observable and measurable overt symptoms. The authors report the successful use of awareness techniques to exaggerate the subjective experience of these covert symptoms and encourage the use of these techniques as an adjunct to the counseling and desensitization procedures traditionally employed. A transcribed clinical management session in which several awareness techniques are used to aid the client in an introspective examination of “anticipation of stuttering,” is analyzed in order to reach some specific recommendations for using awareness techniques in the clinical management of the covert symptoms of stuttering.     

Sex stereotypes: Issues of change in the 1970s

A sample of 128 college males and females rated a typical and desirable man or woman on 54 items taken from the Personal Attributes Questionnaire (PAQ). Comparisons of the ratings of a typical man versus a typical woman yielded significant differences (p<.01) on 53 of the 54 items. Thus, stereotypes of the sexes apparently remained strong during the 1970s. Comparisons of the ratings of a desirable man versus desirable woman yielded significant differences on only 12 of the 54 items. These results are interpreted as reflecting a difference between stereotypes (of the typical person) and attitudes (about desirable characteristics). While atttitudes may have changed in the 1970s, stereotypes remained remarkably stable.     

An improved circuit for control of LED luminance

The light-emitting diode (LED) is becoming increasingly popular as a luminance source in behavioral research. We describe a simple, inexpensive LED driver circuit that produces luminances almost linearly proportional to an input voltage. Negative feedback provides a stable output. Unlike previous designs, the LED is ground referenced.     

Reliability and validity of the revised fear survey schedule for children (FSSC-R)

In this study, the validation of a Revised Fear Survey Schedule for Children (FSSC-R) is detailed. Psychometric properties of the scale are reported for two normal samples and one clinical sample of school-phobic children. Initial analyses indicate that the FSSC-R possesses high internal consistency, high test-retest reliability and acceptable stability over time. Further, it adequately discriminates between normal and clinical samples, has acceptable convergent and discriminant validity and possesses a meaningful factor structure. The potential clinical utility of the scale is discussed, and important social and developmental issues affecting the development and expression of fear in children are addressed.     

A preliminary report on the nature of interactions in a mental-handicap institution

A preliminary analysis of the reactions by staff and other residents to the behaviour of mentally-handicapped people living in a medium-sized institution is presented. The subjects' behaviour was categorized as appropriate, inappropriate or neutral according to culturally-normative criteria. It was found that, for the majority of time there was no reaction to the subjects' behaviour by staff or by other residents. The implications of utilizing culturally-normative criteria for categorizing behaviour are discussed. It is proposed that this type of analysis is potentially useful for understanding the nature of interactions in institutions.     

The role of marking when reward is delayed

Two-choice spatial discrimination by rats is enhanced if a salient stimulus marker occurs immediately after every choice response and again after a delay interval (Lieberman, McIntosh & Thomas, 1979). Three experiments further explore this effect. Experiment 1 found that the second marker is unnecessary. Experiment 2 found that a marker presented before a response is as effective as one presented after. Both effects could be explained in terms of markers focusing attention on subsequent cues. Experiment 3, however, found that markers after choice enhance learning even when no discriminative cues are present following the marker. Markers thus appear to initiate both a backward search through memory and attention to subsequent events; both processes help to identify events that might be related to the unexpected marking stimulus.