Some social contexts of self-destructive behavior

This study investigated the social context of self-injurious behavior in autistic, schizophrenic, and mentally retarded children residing in a state hospital. Social interactions between subjects and staff were recorded along with subjects' self-destructive behavior. The results showed a substantial increase in self-destructive behavior following the staff's presentation of demands, denials, and punishments in 19 of the 20 subjects. These results are consistent with the hypothesis that self-injurious behavior is a social behavior, which is determined by persons in the environment. In addition, the self-destructive behavior of one subject may have been largely self-stimulatory in nature.     

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.     

Visual control of discrete aiming movements

An experiment is reported which investigated the visual control of discrete rapid arm movements. Subjects were required to move as rapidly as possible to several target width-movement distance combinations under both visual and non-visual conditions. The movement time (MT) data were supportive of Fitts' Law in that MT was linearly related and highly correlated to the Index of Difficulty (ID). MT was also similar for different target width-distance combinations sharing the same ID value. The error rate analysis, which compared visual to non-visual perfromance, indicated that vision was only used, and to varying degrees, when MT exceeded 200 ms (3.58 ID level). There was some evidence that vision was differentially used within target width-distance combinations sharing the same ID. Estimates of endpoint variability generally reflected the results of the error rate analysis. These results do not support the discrete correction model of Fitts' Law proposed by Keele (1968).     

Converging evidence for the functional significance of imagery in problem solving

Two kinds of explanations have been offered for the process by which three-term series problems are solved, one in terms of linguistic principles and the other in terms of visual-spatial imagery. Two experiments are reported in which three different classes of operations are brought to bear on the problem: (1) Manipulation of stimulus attributes (characteristics of problems), (2) manipulation of variables that selectively encourage or inhibit the use of imagery (facilitating instructions; the suppression of visualization by reading), and (3) measurement of relevant individual differences (spatial-reasoning ability). All of the results indicate that imagery plays a functional but not a necessary role in the solution of three-term series problems; it is suggested that imaginal representation is functional because it reduces the load on memory. An adequate explanation of problem-solving will have to address certain general issues, such as the diversity of forms of cognitive representation and differences within and between individuals in the choice of problem-solving strategies.     

“in”, “on”, and “under” revisited

The present study presents evidence that young children's comprehension of the locatives ‘in’, ‘on’, and ‘under’ is, at least in part, contextually determined. Children aged 1;6–3;0 were given tasks with verbal instructions which were either contextually congruent or incongruent. The results were interpreted in terms of the non-linguistic as well as linguistic strategies apparently used to interpret speech. The results and interpretation are in contrast to those of earlier research.     

Multiple criteria follow-up of behavior modification with families

This report presents termination and follow-up evaluations of a parent training program based on behavior modification principles. Treatment termination outcome data were obtained for 22 families, and follow-up data were collected on 14 of these families 3 and 8 months after treatment. Results indicated a fairly high level of success at termination on the basis of parent-collected observational data, parent attitude change toward the children, and parent attitude concerning the process and outcome of treatment. Modest levels of success were evidenced on the basis of behavioral data recorded by trained observers in the home. Families who participated in follow-up demonstrated greater cooperation and involvement with the treatment program than those who did not participate. In all other respects, however, these two groups were similar. Follow-up data on parent attitude measures demonstrated maintenance of the treatment effects. Parent observational data were incomplete, but also showed maintenance in follow-up. For the subsample of 14 cases, home observation records indicated a nonsignificant decline in deviant behavior at termination followed by a nonsignificant increase in deviant behavior during follow-up. The meaning and implications of these discrepant findings were discussed and compared with results from other laboratories.     

Some theorems on structural consequence operations

Two characterizations are given of those structural consequence operations on a propositional language which can be defined via proofs from a finite number of polynomial rules.     

Fragmentation of fixated line stimuli as a function of gravitational orientation

The differential propensity of fixated line stimuli to fragment and disappear from view was studied as a function of the gravitational orientation of the stimuli. The propensity to fragment was measured in terms of three intercorrelated dependent variables: the number of fragmentations per fixation period, the total duration of fragmentation per fixation period, and the latency to the first fragmentation. Unlike some anisotropic visual phenomena, which may reflect orientation-independent aspects of pattern perception, the observed anisotropy of propensity to fragment can be attributed overwhelmingly to the retinal orientation of the stimuli. Accordingly, this property of fragmentation need nof be ascribed to higher order aspects of pattern perception.     

Sensory and motor impairment in the nerve compression block

Recently nerve compression block as a method of investigating movement control without kinaesthetic feedback has been questioned on the grounds that motor impairment (as measured by nerve conduction parameters) is a confounding factor. In order to clarify the relationship between sensory and motor function, behavioural data was obtained on both at systematic time intervals throughout the duration of the block. The findings indicated that significant decrements in tapping measures occurred somewhat earlier in the time course of the block than decreases in kinaesthetic discrimination. Also, contrary to assumption, the majority of subjects ceased to perform prior to total kinaesthetic loss. The data suggest that motor impairment is a “crucial” issue (Laszlo, 1966) in the use of this technique, and provide further behavioural support for the neurological findings of Kelso, Stelmach and Wanamaker (1974).