The sensory basis of avoidance responding in the rat : Relative dominance of auditory or visual warning signals and safety signals

Three experiments determined the relative degree of stimulus control exerted by the elements of a compound auditory-visual stimulus when this stimulus was presented in various temporal relationships to a barpress avoidance response. When the compound discriminative stimulus for barpress avoidance responding consisted of onset of white noise and onset of either light or darkness, the white noise always exerted dominant control. When the compound discriminative stimulus consisted of offset of white noise and onset of light, neither element controlled avoidance responding. On the other hand, when a barpress avoidance response produced a compound feedback stimulus consisting of onset of white noise and onset of either light or darkness, the visual element always exerted dominant control. When the compound feedback stimulus consisted of offset of white noise and onset of light, both elements exerted stimulus control.     

Reinforcing fluency in stutterers: An experimental study

Subject-specific periods of fluent reading responses of three adult stutterers were positively reinforced with the presentation of a dime. Subjects were run individually through a sequence of two base rate, two experimental, and two extinction sessions, each session lasting 45 min. Periods of fluent reading responses increased during the experimental condition for each of the three subjects. When the reinforcer was withdrawn during the extinction condition, the frequency of fluent periods showed a decrease. Concomitantly, disfluencies decreased during the experimental condition and they increased during the extinction condition. The clinical implications of fluency manipulation as against disfluency manipulation are discussed.     

A technique for controlling speech disfluencies induced by delayed auditory feedback

On the basis of cybernetic models of speech it was hypothesized that “stuttering” induced by delayed auditory feedback could be significantly reduced if the Ss were provided with an alternate input to which they could attend. The results of the experiment supported the hypothesis. The possible implications for the treatment stuttering are discussed.     

Numerical taxonomy of aphasia

Two hundred consecutively seen aphasics, 142 of them with infarcts, were examined by tests of fluency, comprehension, repetition, naming, and information content. The language scores were subjected to a minimum variance clustering algorithm separately for the total and for the infarct groups. The latter generated 10 clusters on a dendrogram. Attribute analysis of each cluster provided a clinically meaningful profile of language performance for these groups. The degree of correlation of most computer generated clusters with clinically recognized groups was high, and the homogeneity of some of the clusters is striking. An exception appears to be “conduction aphasia,” which is bimodally distributed. One of these clusters, with high fluency and low comprehension scores, was renamed “afferent conduction” aphasia, and the other, with lower fluency and higher comprehension, was renamed “efferent conduction” aphasia. The Principal Components Analysis was used to evaluate the discriminatory value of language characteristics, and the Nearest Neighbor Network Analysis was used to evaluate the significance of clustering. The dendrogram for all aphasics showed a less specific and less homogenous six clusters.     

The processing of fundamental frequency in a dichotic matching task

The temporal characteristics of auditory memory were investigated using a reaction time paradigm. The study attempted to determine whether or not there are functionally distinct left and right hemisphere components of auditory memory with different capacities for the retention of nonlinguistic information, such as fundamental frequency, over the course of several seconds. The results indicated that fundamental frequency information in auditory memory remains substantially unchanged over the course of 2 sec. No evidence was found for the existence of separate left and right hemisphere components of auditory memory with different temporal characteristics. The implications of this finding for the organization of auditory memory in the brain are discussed.     

Aphasia in a polyglot

A Greek-born aphasic who had been able to speak four languages (Romanian, Russian, Greek, German) was tested quantitatively for verbal expression (standard interview indexes) and verbal reception (fifth part of the Token Test). The form of aphasia (qualitative aspect) was found to be identical for all four languages. Quantitatively, his performance in the four languages was different, with the languages used most during the past 20 years (Romanian and Russian) being less impaired. Nevertheless, verbal reception was equally impaired quantitatively in all four languages. Treatment with semantic-syntagmatic methods performed in Romanian had a beneficial effect on speech in the other languages as well. The authors feel that the expressive disturbance noted in aphasia reflects involvement of deep as well as of surface structures of language, but the receptive disturbance reflects involvement of the deep structures only. This may account for quantitative discrepancies in expression without discrepancy in reception among the four languages, as well as the qualitatively identical features of the disturbance in verbal expression and reception.     

A different form of agraphia: Syntactic writing errors in patients with motor speech and movement disorders

Three patients are described who displayed syntactic writing errors in combination with a motor speech disturbance and impaired motor limb function. Two of the patients had bulbar amyotrophic lateral sclerosis (ALS). Agraphia appeared when verbal communication was no longer possible. Autopsy in one patient disclosed only lesions consistent with ALS. The third patient had palilalia and chorea and, although not aphasic, his written language showed persistent syntactic errors. We hypothesize that the agraphia in these patients occurred because of the combination of disordered feedback from the motor speech apparatus and limbs.     

Sex differences in instigative aggression

The instigative aggression paradigm, in which male and female subjects instructed a female confederate which shock to set for an opponent in a competitive reaction time task, was employed. It was observed that males instigated more aggression than females and that both passive and assertive noncooperation effectively reduced instigative aggression, the assertive form of noncooperation being only slightly less effective. Questionnaire data suggested that females found the passive noncooperator most desirable while males found her least so. Results were discussed in terms of violation of task role and sex role expectations.     

Third party instigation of aggression as a function of noncooperation and veto power

The purpose of the present study was to test the validity of three hypotheses previously offered to explain the attenuating effects of pacifistic noncooperation on instigative aggression. During part one of the experiment all subjects served as instigators; in the second part they actually set shocks for the target. Subjects instigated either a cooperative or noncooperative confederate, and either did or did not have veto power over the confederate's shock selections. Results of the study indicated that all hypotheses, norm-conformity, compliance, and maintenance of power, were viable for subgroups of subjects. Results were discussed in terms of individual differences and the temporarily inhibiting effects of passive resistance.