Hemisphere functioning and motor imitation in autistic persons

Previous research has found that a high proportion of autistic individuals exhibit an atypical pattern of hemispheric specialization suggestive of impaired left hemisphere functioning: namely, right hemisphere dominance for both verbal and visual-spatial processing. Studies of brain-damaged persons have suggested that the left hemisphere is specialized for the use of nonverbal gesture. Since a major characteristic of autism is an impairment in the use of gesture, it was predicted that autistic persons would also show atypical hemispheric specialization for motor imitation. To test this hypothesis, hemispheric activation was measured using EEG recordings of alpha rhythm in autistic and matched normal control subjects during four motor imitation tasks. Autistic subjects showed significantly greater right hemisphere activation during the imitation tasks, than normal subjects. This pattern was particularly evident in younger autistic subjects and during oral, rather than manual, imitation tasks.     

Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

Visual masking,mental age,and retardation

Performance of retarded subjects under both forward and backward masking was less accurate than either an equivalent chronological age or equivalent mental age group of normals. It was suggested that the iconic memory impairment of retarded subjects in attributable in part to mental retardation and not simply to low mental age.     

Concomitant changes in classically conditioned heart rate and corneoretinal potential discrimination in the rabbit (Oryctolagus cuniculus)

Corneoretinal Potential (CRP) and heart rate changes were measured in a series of differential classical conditioning experiments in which the directionality of the heart rate response was related to (a) CRP acquisition, and (b) the certainty or uncertainty of the stimulus situation. The results suggested that heart rate decelerations were associated with stimuli that predict upcoming aversive events, while heart rate accelerations were associated with asymptotic CRP responding late in conditioning. These findings were interpreted in terms of (a) changes in general somatic activity, and (b) the cue properties associated with CSs which predict aversive events.     

Reply to Fishbein and Ajzen

The purpose of the Songer-Nocks study was clarified, and the relationship of the predictions and results to the theoretical formulations of Fishbein and Ajzen were discussed. Results from the model-testing procedure originally performed with behavior as the criterion were presented using behavioral intention as the criterion. The findings revealed that the interactive effect of prior experience with attitude toward the act in predicting behavioral intention was not significant, and that the interactive effect of motivational set with normative belief in predicting behavioral intention was significant. In addition, a regression analysis of the BI-B relationship was performed in which the design variables were incorporated as predictors. Results showed that the inclusion of design variables aided the prediction of behavior significantly. Songer-Nocks' data were interpreted as being consistent with the overall Fishbein formulation, but as suggesting certain potentially specifiable limitations in predicting actual behavior from attitudinal components.     

Using conjoint-measurement models to investigate a theory about probabilistic information processing

A theory of how opinions are formed and revised on the basis of probabilistic evidence is presented. The decision maker is viewed as a limited information processor who attends to the dimensions of a sample of equivocal information in a sequential fashion, beginning with the most salient dimension and continuing in decreasing order of salience. The contribution of each dimension level to the final opinion depends on the strength of association between that level and each of the two hypotheses under consideration. This theory is represented formally as an additive-difference model, various special cases of which correspond to other algebraic models in the literature. Two of the special cases were empirically investigated under varying levels of experience and payoffs, using the techniques of conjoint-measurement theory and ordinal data from individual subjects. The data provided reasonably good support for the models under all conditions investigated, and in addition showed interesting effects on salience and on processing of the independent variables.     

Information extraction during visual search: A developmental progression

Five developmental experiments examine the role of context in visual search. Experiments I and II presented either lists or paragraphs that were either in meaningful context or scrambled. Results showed a significant interaction of these variables. Experiment II examined within-item context or predictability and replicated and extended the work of Brand (1971) and Ingling (1972). Experiments IV and V examined search through lists of various widths; results showed a significant interaction of Grade × Position × Width reflecting the different perceptual spans of children and adults. Although these were search tasks, appropriate comparisons between list and paragraph performance were made allowing interpretations of the results to be supportive of a model of reading in which meaningfulness, predictability, and peripheral vision play critical roles.     

Spatial representation by blind and sighted children

Spatial representation by 72 blind and blindfolded sighted children between the ages of 6 and 11 was tested in two experiments by mental rotation of a raised line under conditions of clockwise varied directions.Experiment 1 showed that the two groups were well matched on tactual recognition and scored equally badly on matching displays to their own mentally rotated position.Experiment 2 found the sighted superior in recall tests. There was a highly significant interaction between sighted status and degree of rotation. Degree of rotation affected only the blind. Their scores were significantly lower for rotating to oblique and to the far orthogonal directions than to near orthogonal test positions. On near orthogonals the blind did not differ from the sighted.Age was a main effect, but it did not interact with any other variable. Older blind children whose visual experience dated from before the age of 6 were superior to congenitally blind subjects, but not differentially more so on oblique directions.The results were discussed in relation to hypotheses about the nature of spatial representation and strategies by children whose prior experience derived from vision or from touch and movement.