Processing of stimulus properties: evidence for dual-task integrality

The conditions under which dual-task integrality can be fostered were assessed in a study in which we manipulated four factors likely to influence the integrality between tasks: intertask redundancy, the spatial proximity of primary and secondary task displays, the degree to which primary and secondary task displays constitute a single object, and the resource demands of the two tasks. The resource allocation policy is inferred from changes in the amplitude of the P300 component of the event-related brain potential. Twelve subjects participated in three experimental sessions in which they performed both single and dual tasks. The primary task was a pursuit step tracking task. The secondary tasks required subjects to discriminate between different intensities or different spatial positions of a stimulus. Task pairs that required the processing of different properties of the same object resulted in better performance than task pairs that required the processing of different objects. Furthermore, these same object task pairs led to a positive relation between primary task difficulty and the resources allocated to secondary task stimuli. Intertask redundancy and the physical proximity of task displays produced similar effects of reduced magnitude.     

The autistic moment in psychotherapy

This is a report on the author's experience in treating four autistic children and their families. The importance of making available the therapist's own autism is stressed. The difficulty in doing this and reverting defensively to an administrative approach is described. A previous paper discussed the corrective autistic experience with a focus on the autistic person. This follow-up describes the autistic moment which is a relational experience between the therapist and both the autistic person and the autistic family. The family needs to have an experience of its own autism as a continuum of normal before it can relate to an autistic child. To the extent that the therapist can bring his own autism into the therapy can the family experience its own. The patients are the person, the relationships, the family, and the therapist.The author would like to thank Richard B. Anderson, MD, Lindy T. Barnett, MSW, David V. Keith, MD, JoEllen Barnett Smith, MA, and Orion Smith for their participation as cotherapists. The comments made on an earlier draft of this paper by the members of the Atlantic Psychiatric Clinic are warmly acknowledged. Valuable editorial assistance has been extended by Robert Garfield, MD, and Stuart Sugarman, MD. Lastly, the author would like to extend his appreciation to Robert R. Haubrich, PhD, for stimulating his interest in the field of comparative ethology.Presented at the Conference Honoring the Retirement of Carl A. Whitaker, MD, in Madison, Wisconsin, June 25, 1982.     

The language of social pretend play

The literature dealing with the structure and communication of social pretend play activity in preschool-age children is examined. The two objectives of this review were to determine (1) whether there are any differences in the linguistic forms and expressions children use in pretend as opposed to nonpretend activity and (2) whether age-related differences appear in the language of social pretending over the preschool years. The results of a cross-sectional study of a number of linguistic features occurring in the pretend and nonpretend activities of 35 dyads of children are also presented. The evidence supports the hypotheses that the language of social pretending differs from that of other social activities at several levels of language organization and that some of these differences in the “language of social pretending” appear at different ages during the preschool years. Suggestions are made for further research on the communicative techniques by which social pretend interactions are achieved.     

Visual marking of old objects

Watson and Humphreys (1997) presented evidence that selection of new elements can be prioritized by on-line top-down attentional inhibition of old stimuli already in the visual field (visual marking). The experiments on which this evidence was based always presented old elements in green and new elements in blue. Because of this, instead of prioritizing new objects by inhibiting old objects, selection could have been based on color. The present experiment, which does not contain this confound, showed that visual marking is a strong and robust process that enables subjects to visually mark at least 15 old elements even when these elements have the same color as the new elements. The results indicate that preview of the elements is critical—not the fact that those elements contained a common feature.     

Application of the Generalized Matching Law for Description of Student Behavior in the Classroom

Matching law and theory have applied implications for classroom instruction and student behavior. The Generalized Matching Law (GML) is examined in this exploratory study to assess its utility for quantitatively describing student behavior in the classroom. Data were collected using computer-based observational software. Time-lag sequential analysis was used to identify specific teacher behaviors following specific student behaviors as estimates of reinforcement. Derived rates of student and teacher behaviors were analyzed in a linear regression of the natural logarithmic form of the GML. On average, the GML described over 70% of the variance in two students' behavior in a first-grade regular education classroom. Discussion addresses the potential utility of the GML for observation and intervention in the classroom.     

Offset transients modulate attentional capture by sudden onsets

Recent research with visual search tasks has suggested that stimuli which appear as sudden onsets (new objects) have attentional priority over stimuli that are created by removing segments of premasks (non-onset stimuli). Attentional capture by sudden onsets occurs despite the fact that the appearance of these new objects predicts neither the identity nor the location of the target in the visual search task. In three experiments, we examined the extent to which attentional capture by sudden onsets could be modulated by offset transients used to create non-onset objects. To that end, we systematically manipulated the ratio of non-onset to onset stimuli in the display (display ratio) as well as the ratio of offset to onset segments between the stimulus types (stimulus ratio). Increases in either the stimulus ratio or the display ratio resulted in increases in the visual search slopes for the onset targets. These results suggest that the ability of sudden onsets (new objects) to capture attention is influenced by stimulusdriven factors, such as environmental change. Interestingly, the results also indicated that goal-directed or purposeful search for sudden-onset (new-object) targets was relatively uninfluenced by the amount of change in the visual display. Therefore, it would appear that environmental change has differential effects on goal-directed and stimulus-driven search. These results are discussed in terms of their implications for our understanding of attentional capture.