The interaction between stimulus and reinforcer control on remembering.

In a symbolic matching-to-sample task, 6 pigeons obtained food by pecking a red side key when the brighter of two white lights had been presented on the center key and by pecking a green side key when the dimmer of two white lights had been presented on the center key. Across Part 1 and Parts 6 to 10, the delay between sample-stimulus presentation and the availability of the choice keys was varied between 0 s and 25 s. Across Parts 1 to 5, the delay between the emission of a correct choice and the delivery of a reinforcer was varied between 0 s and 30 s. Although increasing both types of delay decreased stimulus discriminability, lengthening the stimulus-choice delay produced a greater decrement in choice accuracy than did lengthening the choice-reinforcer delay. Additionally, the relative reinforcer rate for correct choice was varied across both types of delay. The sensitivity of behavior to the distribution of reinforcers decreased as discriminability decreased under both procedures. These data are consistent with the view, based on the generalized matching law, that sample stimuli and reinforcers interact in their control over remembering.     

Cerebral lateralization in individuals diagnosed as autistic in early childhood

Early infantile autism was found to be associated with an atypical pattern of cerebral lateralization. Based on EEG measures of hemispheric activation during cognitive processing, it was found that 7 of the 10 autistic individuals tested showed a pattern of hemispheric specialization rarely seen in the normal population; namely, a “reversal” in lateralization reflective of a lack of left-hemisphere specialization for linguistic functions. Furthermore, the autistic individuals' pattern of cognitive strengths and weakness is suggestive of a selective impairment of the left cerebral hemisphere.     

A study of language functioning in Alzheimer patients

Language functioning in Alzheimer's disease is reviewed and the performance of 25 Alzheimer patients on a standard battery is reported. All these hospitalized patients were aphasic to some degree. As a group, they differed from normals on all language variables, and from stroke patients in terms of higher fluency and lower comprehension. Spontaneous speech showed high incidence of circumlocutions and semantic jargon, but no phonemic paraphasias or target approximations. Syllabic perseverations, shouting, inappropriate laughter, and mutism were late-appearing features. Transcortical Sensory, and Wernicke's aphasias were frequent, but Broca's and Transcortical Motor aphasias notably absent. Extent of language impairment correlated with current length of hospitalization but not age. Reading, writing, and performance scores except praxis, were lower than oral language scores. Findings were discussed in relation to previous results, methodology, and language organization in the brain.     

Mirror-reading in right- and left-handers

In mirror-reading, words are read from right to left and letters are read in a reverse right-to-left orientation. In one experiment we compared the ability of normal right- and left-handed subjects to mirror-read and found that the left-handers made fewer errors and could read mirror print more rapidly. In a second experiment we attempted to learn whether there is a hemifield superiority for reading mirror words and whether there are any differences between left- and right-handers in a hemifield. We found that although both right- and left-handers more rapidly detected mirror words projected to the left visual half-field, there were no differences between groups. However, in the right visual half-field, the performance of left-handers was superior to that of the right-handers. The results of the hemifield study suggest that left-handers may be superior at reading mirror words because they can more easily reverse their scanning pattern.     

Aphasics' selective deficits in appreciating grammatical agreements

This study attempted to dissociate in aphasic patients different aspects of grammatical capacity. Subjects were asked to evaluate sentences containing violations of agreements between pronouns and verbs. Agreements which are considered primarily structural in nature were violated (e.g., a surface object case like “them” placed in a surface subject sentential slot) while other violated agreements seemed to involve both structural and semantic information (e.g., lack of agreement between a pronoun and a verb in terms of the number of people performing the act). These violations were couched in one of three types of sentential frames which varied in terms of syntactic complexity (e.g., active declarative vs. passive syntactic voices). The results revealed that Broca's aphasics found agreement violations difficult to detect in complex syntactic frames. They were quite successful at detecting even violations of the largely structural “case” type of agreement, however, when couched in simpler syntactic frames. Fluent aphasics encountered more difficulty detecting violations of agreements involving both semantic and structural information than agreements which were primarily structural in nature, that is, regardless of the syntactic frame. These unique performance profiles suggest that Broca's aphasics may be agrammatic only with respect to certain aspects of a sentence's structure, and that fluent aphasics may also experience some selective—but different—grammatical deficits.     

Visual and verbal modes of information processing and their relation to the effectiveness of cognitively-based anxiety-reduction techniques

This study examined the interaction between preferred modes of information processing (visual and verbal) and two cognitively-based anxiety-reduction techniques. One technique was based on the use of images as a coping strategy while the other employed a self-instructional approach. Thirty-six subjects reporting high levels of dental fear were assigned to one of three groups (two types of treatment and a no-treatment control). One-half of the subjects in each group had been identified as preferring the visual mode of information processing while for the other half the verbal mode was preferred. After treatment, subjects viewed an anxiety-inducing videotape depicting a visit to the dentist. Results indicated that, while both treatments were significantly effective in reducing self-reports of discomfort while viewing the videotape, there was no significant interaction between the type of treatment and preferred cognitive mode. The results were interpreted as indicating that treatment may override individual cognitive styles. Furthermore, the data suggested that the normal individual has the ability to adapt to divergent and non-preferred forms of information processing.     

Autonomic responsivity of subjects with body boundary differences during white noise stimulation

A white noise stimulus (85 dB) was used to investigate differences in heart rate (HR) and skin conductance (SC) responsivity of 32 male subjects. The subjects were divided into high and low body boundary (HB and LB) groups, according to Fisher's (1970) revised scoring system of Holtzman Inkblot responses. The hypothesis predicting a significantly larger HR response, that is resistant to habituation, for the LB group, was confirmed. The prediction that the HB group would reveal a larger SC amplitude response accompanied by a shorter recovery time, was supported for the latter. The results confirmed the hypothesis, based on behavioral observations, that the HB individual experiences stress less intensely than the LB person. It also points to individual differences as an important variable in evaluating noise as a stressor.