Profiles of symbol-reading skills in organic patients

One (unitary) school of thought views all symbolic competences as closely related, while a rival (pluralistic) approach underscores the relative differences among modes of symbolic processing. To secure information on the plausibility of these competing hypotheses, matched groups of left- and right-hemisphere patients were given a visual symbol-recognition test. Subjects were required to choose the correctly depicted symbol among a set of four. The results challenge a strong version of the “unitary” hypothesis. What emerges instead is a view of symbol systems as a continuum: relatively linguistic symbol systems prove challenging for left-hemisphere patients, relatively nonlinguistic systems pose comparable difficulties for right-hemisphere patients. Contrary to hypothesis, the processing of numerical symbols poses special difficulty for right-hemisphere patients. Performance on trademarks—items which can be processed by linguistic or nonlinguistic strategies—suggests that organic patients with contrasting pathologies may adopt different processing strategies when confronting identical physical stimuli.     

Semantic field,naming, and auditory comprehension in aphasia

The status of semantic fields for 16 target nouns was compared in high and low comprehension aphasics, brain damaged, and normal controls, by measuring latency and miss rate for recognition of six classes of associates, which were presented orally on tape. The ability to name each target was also examined as a function of the integrity of the subject's semantic field for that word. Low comprehension aphasics showed both quantitative and qualitative changes in semantic fields, while milder aphasics showed only mild quantitative impairment, as compared to controls. Both latency and miss rate measures indicated that failure to name a word is associated with reduced semantic field for that word. This result is interpreted as supporting the view that nameing is, in part, determined by the convergence of associations.     

Rehearsal strategies of Alcoholic Korsakoff patients

An overt rehearsal procedure was used to monitor the rehearsal strategies that Alcoholic Korsakoff, Chronic Alcoholic, and Normal Control patients used when learning a 20-item list. It was found that Korsakoff patients spontaneously rehearse only one word at a time, that word being the one currently presented, regardless of the organizational salience of the list of words. Alcholics and Control patients, on the other hand, tended to rehearse several words in addition to the one being currently presented, and they demonstrated increasing ability to rehearse semantically related words together as the organizational salience of the list increased. This ability to rehearse in an enriched manner placed the two control groups at a distinct advantage over the Korsakoff patients at the time of recalling the list.     

When three is not always two against one: Coalitions in experimental three-person cooperative games

Four models of coalition formation are tested in a computer-controlled experiment in which three players negotiated to form coalitions in order to gain rewards for themselves. Formation of the grand coalition of all three players as well as any of the three possible 2-person coalitions is permitted. The results indicate that the grand coalition is the most likely to form, followed by the coalition between the two strongest players. The individually rational bargaining set model of coalition formation is supported over an egalitarian model, the Shapley value, and the coalitionally rational bargaining set model. Various measures of the progress of negotiations are introduced, examined, and discussed in an effort to provide an increased data base for the establishment of a behavioral theory of bargaining and coalition formation.     

Verbal retention deficits in aphasic and amnesic patients.

Five different groups of patients (aphasics, alcoholic Korsakoffs, nondominant hemisphere patients, alcoholics, and control patients) were asked to detect either repeated letters, repeated words, rhyming words, or words from the same category during the reading of a list. It was discovered that the number of intervening words had a greater effect on the aphasics for all conditions than it did for the other groups. However, when the rate of presentation was slowed, the aphasics showed considerable improvement while the other groups maintained their same level of performance. The Korsakoff patients were impaired only on the semantic task (same category inclusion) and did not improve at the slower presentation rate. An interpretation based on speed and level of information processing abilities is given.     

Distraction effects in tasks of varying difficulty: Methodological issues in measuring development of distractibility

Effects of distraction on 5- and 8-year-old children's performance on a short-term memory task were examined. Tasks at three difficulty levels were employed to determine whether a floor effect could account for the lack of an age difference reported in an earlier study. A floor effect does not appear to be a key factor; the absolute amount of performance decrement was roughly equal for the two ages here regardless of task difficulty, and performance was well above chance under all conditions. The children adapted somewhat to the presence of distraction as shown in greater performance impairment for the first trial under distraction than for remaining trials. Use of a proportional, rather than an absolute, decrement index was considered, and the relevance of the present data to this issue was discussed.     

The relation between gesture and language in aphasic communication

Effective communication in aphasia depends not only on use of preserved linguistic capacities but also (and perhaps primarily) on the capacity to exploit alternative modalities of communication, such as gesture. To ascertain the capacity of aphasic patients to use gesture in their spontaneous communication, informally structured interviews were conducted with two Wernicke's aphasics and two Broca's aphasics, as well as with four normal controls. The performances of the patient groups were compared on the physical parameters of gesture, the points in the communication where gestures occurred, and several facets of the semantics and pragmatics of gesture. Generally speaking, the gestures of the aphasics closely paralleled their speech output: on most indices, the performance of the Wernicke's aphasics more closely resembled that of the normal controls. Wernicke's aphasics differed from normals in the clarity of their language and gestures: While individual linguistic units were often clear, the relation among units was not. In contrast, the Broca's aphasics equaled or surpassed the normal controls in the clarity of their communications. The results offer little support for the view that aphasic patients spontaneously enhance their communicative efficacy through the use of gesture; these findings can, however, be interpreted as evidence in favor of a “central organizer” which controls critical features of communication, irrespective of the modality of expression.     

The structure of interests as a structure of occupational stimuli and as a structure of affective responses

The structure of interests has usually been perceived as a structure of occupational stimuli, but it can also be conceived of as a structure of the affective responses that occupational stimuli elicit, or as a structure of these stimuli embedded within the matrix of affective responses which they produce. Each of these three structural representations was examined in this study. The semantic differential technique was used to rate a set of 10 occupational stimuli with 15 bipolar scales. A factor analysis of the stimuli yielded three occupational factors called Science, Things vs. People, and Social Welfare; a factor analysis of the scales indicated that the stimuli elicited Evaluation, Potency, and Activity responses. The three dimensions of affect were then used as the axes of a semantic space within which the occupational stimuli were located according to the unique affective meaning of each. The desirability of studying the structure of interests as a structure of occupational stimuli embedded within a structure of the responses they elicited was discussed.