Multiple component agraphia in a patient with atypical cerebral dominance: an error analysis

A 52-year-old man with atypical cerebral dominance (left-handed for writing but mixed handedness for other tasks) suffered an extensive right hemisphere stroke, resulting in a combination of deficits that has not been previously reported. There were profound visual constructive and visual perceptual disturbances and a spatial agraphia, which were consistent with a nondominant hemisphere lesion. There was also a severe apraxic agraphia, which is typically associated with a dominant hemisphere lesion, but no other signs of dominant hemisphere dysfunction such as linguistic disturbance or limb-motor apraxia were present. This case serves to highlight the functional and anatomical relationship between handwriting and other forms of praxis; the various sources of error in letter formation; the need to be specific in labeling and describing agraphias ; and the role of a detailed analysis of writing errors in delineating the neuropsychological processes involved in handwriting.     

Patterns of vocal fold movement during stuttering

By means of an electroglottography, 114 tokens of stuttering produced by 12 adult stutterers were analyzed for patterns of vocal fold vibration as observed in eight types of stuttering episodes. Results suggest that stuttering events share certain phonational attributes. Issues concerning the nature of the disorder and approach to treatment are discussed.     

On the inconclusiveness of “crucial” cognitive tests of dissonance versus self-perception theories

Several recent experiments are claimed to have tested conflicting predictions of cognitive dissonance and self-perception theories. It is argued that these claims fail to take into account the capacity of each formulation to account adequately for results “predicted” by the other. This argument is then continued, at a metatheoretical level, to reach the conclusion that the two theories are not capable of producing unequivocally contradictory predictions of cognitive consequences of experimental procedures.     

Stimulus intrusion on fixed-interval responding in the rat: The effects of electric shock intensity,temporal location,and response contingency

After a scalloped lever-press response pattern had developed under a fixed-interval food reinforcement schedule, a 15-sec electric shock was intruded for different groups of rats in the first, second, third, or fourth quarter of each inter-reinforcement interval. Shock intensity was systematically increased for individual rats over 70 sessions, from 0.05 to 1.6 mA. Additional between-groups comparisons involved response-dependent versus clock-dependent fixed-interval schedules, and response-dependent versus response-independent electric shock intrusion. Response rates within each fixed interval prior to, during, and following electric shock intrusion showed regular and reproducible increases and decreases under systematic application of the experimental variables. These results provide further evidence that the functions of a stimulus are determined in part by the parameters of intensity, response contingency, and temporal location with respect to reinforcement.     

Effects of directiveness of instructions and surveillance on the production and persistence of children's donations

All subjects earned tokens for correct size judgments and observed a model who had previously earned tokens at the same task donate some of her earnings. Children were subsequently given an opportunity to donate some of their tokens to children at another school. The opportunity to give occurred in presence (surveillance) or absence of the experimenter and after being presented with either directive (you must give) or permissive (you can give if you want to) instructions. Directive instructions and surveillance both produced greater initial giving for all children. In a second session with no modeling, no surveillance, and no further instructions, earlier directive instructions also produced greater persistence of giving for all children. Permissive instructions produced greater reductions in giving over time for boys than for girls. The present findings suggest that directive instructions produce greater initial giving and that donating persists better under these more explicit conditions.     

Language comprehension in old age

Three experiments examined the effects of aging on comprehension of spoken language. Integrative and constructive aspects of comprehension showed much more marked age-related deficits than registration of surface meaning. Experiment 1 showed that old subjects had difficulty in making inferences based on presented facts. Experiment 2 revealed a similar deficit in old people's ability to detect anomalies in newly presented information by reference to prior everyday knowledge. And Experiment 3, which tested story recall, showed that old subjects were less well able to extract and retain gist information than younger subjects. These difficulties are interpreted as reflecting a limitation in processing capacity such that the demands of concurrently registering surface meaning and simultaneously carrying out integrative and constructive processes exceed capacity in old age.     

The coding and transformation of spatial information

The present paper examines the mental processes involved in inferring perspective changes that result either from the rotation of a spatial array or from the rotation of the viewer of that array. Piaget has shown that viewer-rotation problems are difficult when children must choose among pictures or models of an array from differing perspectives. We showed earlier that, with parallel tasks, array-rotation problems are much easier than viewer-rotation problems. We proposed that in solving these problems, subjects interpret the instructions literally, recoding the position of the viewer vis-à-vis the array for viewer-rotation problems and recoding the array with respect to its spatial framework for arrayrotation problems. At that time, we proposed a second principle to explain why Piagetian perspective problems are so difficult; namely, that children have special difficulty in recoding viewer position (egocentrism). The present experiments show that, when subjects are asked a different sort of question on such tasks, viewer-rotation problems become easy and array-rotation problems become difficult. The results show that the difficulty of the Piagetian perspective task is not due to egocentrism; i.e., to difficulty recoding viewer position. The results of all these rotational-transformation tasks can be explained if we add a different second principle to the principle of literalness of problem interpretation. This new second principle posits that the array is fixed vis-à-vis the spatial context rather than that the viewer is fixed vis-à-vis the array.