Schedule-induced behavior in hyperactive children

A schedule-induced behavior paradigm was used to investigate the activity patterns of hyperactive children in a standardized situation. In Experiment I, 10 hyperactive and 10 normal control children matched for age, sex, and IQ were observed under conditions of baseline and schedule. Measures of a number of categorized activities were taken on a time-sampling basis. Hyperactive children were more active than controls in baseline and did not respond to the schedule, unlike the controls who became significantly more active in schedule conditions. In Experiment II, 12 hyperactive and 6 normal children were again subjected to the same experimental paradigm, but in two of the four experimental sessions the stimulant drug methylphenidate was administered in an attempt to reduce the amount of baseline activity. Results were substantially similar to those of Experiment I, with hyperactive children more active than controls in baseline and insensitive to the schedule. There was no overall effect of drug administration on the behavior of either group. There were some ratedependent effects of both drug and schedule conditions.     

Focused attention in pervasively hyperactive children

This experiment was designed to investigate the hypothesized distractibility of hyperactive children in a focused attention task. Distractibility was defined in terms of Shiffrin and Schneider's model of focused attention as the ability to ignore irrelevant in favor of relevant information. Failure to inhibit processing of irrelevant information indicates a focused attention deficit. Task efficiency in all children decreased when irrelevant information was presented. The mean reaction time, within-subject variance of reaction time, and error percentage all increased compared with a nondistraction condition. Thus, the demands of focused attention, as formulated in the model, were measured optimally. Since hyperactives and controls did not differ significantly with respect to task efficiency in the distraction condition, a focused attention deficit in hyperactives was not demonstrated. The hyperactives did nevertheless make more errors and their responding was more variable than the controls. However, the difference in error percentages between hyperactives and controls was associated with the difference in IQ. It is speculated that the variable responding in hyperactives is caused by a less optimal state of performance unrelated to distractibility.The authors wish to thank L. Leertouwer for making the drawings. This research was supported by grants from the Netherlands Foundation for the Advancement of Pure Research (ZWO) and the Professor Duijker Fund.     

Auditory attention switching in hyperactive children

The ability to rapidly reorient attention in the auditory modality was studied in hyperactive children. Hyperactive and nonhyperactive subjects matched on age, sex, and IQ listened to dichotically presented lists for prespecified targets. Reorientation was studied by comparing performance on trials requiring subjects to reorient their attention during a list to performance on trials requiring no switching of attention. The results indicate that although nonhyperactive children were temporarily disrupted by the switch, they eventually reoriented to the cued ear. In contrast, once hyperactive children were disrupted by the switch, they did not reorient to the cued ear. As the pattern in performance comparing hyperactive and nonhyperactive subjects resembles the pattern previously found in comparing younger and older subjects, these results are consistent with the hypothesis that the auditory reorientation skills of hyperactive children are developmentally immature.     

Methylphenidate in hyperactive children: Differential effects of dose on academic,learning, and social behavior

Methylphenidate (Ritalin) has been shown to have differential effects on hyperactive children's behavior as a function of dose level. In the present investigation, a triple-blind, placebo-control, within-subject (crossover) experimental design was employed in which 12 hyperactive boys between 6 and 10 years received three different dosages of methylphenidate (5, 10, and 15 mg) in a randomly assigned sequence. Dosage effects were assessed on clinic(PAL-Paired Associates Learning test) and school-(percent on task, teacher ratings, work completion rates, and accuracy) related behaviors. For 10 of the children, classified as responders to medication by the PAL using the criteria of Swanson, Kinsbourne, and colleagues, a series of ANCOVAs with repeated measures showed significant dosage effects on teacher ratings (p 01), percent on task (p 01), academic accuracy (p 05), and assignment completion rates (p 05). PAL performance was also significantly enhanced (p 01) after optimal dose levels were considered. Subsequent trend analysis showed a significant positive linear relationship between dose and each of the dependent variables. A comparison of fixed-dose and miligram-per-kilogram plots showed that children's performance across the different dosages were clearly individualistic and task-specific, even when similar body weights were compared. The implications of using clinic-based testing to determine optimal medication responsivity were discussed.We would like to express our sincere appreciation to the following pediatricians for their valuable assistance: W. H. McDermott, D. J. Chronley, R. B. Trivett, F. J. Jehle, P. M. Small, and F. T. Leong. Grateful acknowledgement is also extended to the two anonymous reviewers whose comments contributed to the content of this paper, and to the undergraduate and graduate student members of the Children's Learning Clinic.     

Laterality and selective attention in hyperactive children

Laterality and selective attention were investigated in a group of 20 hyperactive children and their matched controls using a dichotic listening task. There was a strong rightear advantage for both groups indicating that hyperactive children were not different from normal children in hemispheric specialization for verbal stimuli. In the selective attention experiment hyperactive children were again not different from normal children in their ability either to select the input designated as relevant or to resist the distraction of input designated irrelevant. Both groups gave more correct responses from the right ear than from the left ear, and more intrusions from the right ear than from the left. The results do not suggest abnormalities of lateralization for verbal material or indicate the existence of a selective attentional deficit. It is suggested that such reported deftcits may be situation or taskspecific.     

Self-control behavior in hyperactive and nonhyperactive children

This study was aimed at evaluating the self-control behaviors of hyperactive (HA) and nonhyperactive (NHA) first-grade pupils under conditions of repeated failure on a previously learned concept formation task. Subjects were divided into HA and NHA groups on the basis of their scores on the Conners (1969) Teacher Rating Scale. During the training stage of the experiment the children learned a concept formation task under a schedule of contingent positive reinforcement. In the test stage they performed the same task but under a negative noncontingent reinforcement schedule. The results revealed no differences in initial rate of learning the task between the groups. After the introduction of the negative noncontingent reinforcement schedule, however, the HA group showed a marked decrease in the use of effective problem-solving strategies. The HA children's performance on the concept formation task was accompanied by the emission of negative self-evaluations and solution-irrelevant statements. The NHA group used significantly more statements showing useful goal directed cognitive mediations than the HA children. The results suggested that HA children may have deficits in self-control skills.Grateful acknowledgment is made to the two anonymous reviewers whose insightful comments were very helpful in producing the final form of this paper.     

Stimulus-seeking behavior in hyperactive and nonhyperactive children

Auditory and visual stimulus-seeking behavior was measured in hyperactive and nonhyperactive youngsters. The design controlled for motor activity level. The results indicate that hyperactive children preferred auditory stimulation more than the control children. There were no differences in stimulus-seeking preferences in the visual modality. The groups did not differ in motor activity. It was concluded that abnormally high needs for stimulation are important in hyperactivity.The authors would like to express their appreciation to James Fogarty, Superintendent, Walter Galvin, Principal, and the many teachers, students, and parents of the Greene Avenue Learning Center of BOCES II in Sayville, New York for their cooperation and support in this study. We would also like to thank Susan O'Leary, Ph.D. Director of the Point of Woods Laboratory School and the students and parents for participation and support in this study.     

Psychostimulant medication and perceived intensity in hyperactive children

Adult ratings of children's activity, based on impressionistic scales, are good indicators of psychostimulant medication effects. These ratings seldom correlate with objective indicators, however, and their behavioral referents are poorly understood. Two separate studies tested the hypothesis that intensity of child behavior, as perceived by others, would differentiate medicated and unmedicated states. College student subjects assessed randomized videotaped segments of children's behaviors. The perceived intensity of hyperactive children's responses decreased with medication, while there were no medicationrelated changes in either gross motor locomotion or off-task behaviors. In a test for observer sensitization or expectancy, the results for subjects who were looking for medication effects did not differ from those for uninformed subjects.This research was supported in part by NIMH grant 29475 and NIDA grant 01070. We thank Andy Christensen and Carol Whalen for helpful comments.     

Motor performance in hyperactive children treated with imipramine

The effects of the tricyclic antidepressant imipramine were evaluated in a study of 9 children with Attention Deficit-Hyperactivity Disorder. The study was double-blind, placebo-controlled, with three drug conditions, low, medium, and high doses. The focus was on neuropsychological drug effects. Imipramine exerted negative dose-response effects on motor performance (motor speed, motor pursuit), while it improved hyperactive behavior and attention and raised the heart rate slightly.     

Effects of reinforcement on concept identification in hyperactive children

The effects of continuous and partial reward on the performance of hyperactive and normal children on a concept identification task were compared. Because reduction in information feedback is usually associated with partial reward schedules, the study was designed to yield information regarding the contribution of reduced feeback to performance in the partial reward condition. Previous findings of a performance deficit in hyperactives under partial reward were replicated. The findings help rule out an information feedback explanation for this deficit. The authors suggest that a motivational factor involving the elicitation of frustration when expected rewards fail to appear may be responsible for the poor performance of hyperactives on the partial schedule.This research was supported by Grant No. 943-03-34 from the Social Sciences Research Fund, McGill University.     

Assessment of a cognitive training program for hyperactive children

Modeling, self-verbalization, and self-reinforcement techniques were used to train hyperactive children in more effective and less impulsive strategies for approaching cognitive tasks, academic problems, and social situations. Eighteen hyperactive children took part in the training program. The control group, which received no training, consisted of 11 children, matched with the experimental group on age, IQ, and measures of hyperactivity and impulsivity. Several tests and measures, some of which have been shown to differentiate between hyperactive and normal children, were administered prior to training, at the end of the 3- month training period, and after a further 3- month period in which no training took place. The trained group showed significantly greater improvement on several of the measures, both at the time of posttesting and on the follow-up evaluation.This research was supported by Canada Council Grant #S74-0750, principal investigator, Virginia I. Douglas.     

A divided attention experiment with pervasively hyperactive children

Task performance of 12 pervasive hyperactives and controls was studied in a divided attention reaction time experiment. The two groups differed with respect to task efficiency. The hyperactives were slower than controls, had more variable reaction times, and made more frequent errors. Task inefficiency could not be explained by a deficiency in divided attention or impulsive responding in the hyperactive group. Further, the observed differences in IQ between the groups could not account for the differential performance finding. It is concluded that input and/or output processes, probably in combination with energetical factors, might be disturbed in hyperactive children.The authors wish to thank L. Leertouwer for making the drawings, and the students Ellie Wekking and Sipke Boorsma for their selection procedure work. This research was supported by a grant from the Netherlands Foundation for the Advancement of Pure Research (ZWO) and by the Professor Duijker Fund.     

Effects of methylphenidate on inhibitory control in hyperactive children

This study investigated the effects of methylphenidate (MPH) on inhibitory control in hyperactive children. A double-blind, placebo-control, within-subject (crossover) design was used in which 12 children, between 6 and 11 years of age, were each tested four times in each drug condition: 0.3 mg/kg and 1.0 mg/kg of methylphenidate, and placebo. Dependent measures included (a) the probability of inhibiting responses to a primary choice reaction time task given a stop signal, on the Stopping Task, and (b) response latency and errors on the Matching Familiar Figures Test (MFFT). MPH improved the efficiency of the central inhibitory mechanism by speeding the inhibitory process, thereby affording the children greater control over their actions and enabling them to increase the probability with which they inhibited responses given a stop signal. MPH increased response latency but did not reduce errors on the MFFT, and observation of the children's task performance highlighted the interpretive problems associated with this task. Performance on both tasks was better at a dosage of 1.0 mg/kg than at 0.3 mg/kg.     

Lead and hyperactivity: Lead levels among hyperactive children

Previous work has demonstrated an association between hyperactivity and increased body lead burdens in school-age children. In the present study it is shown that within a group of hyperactive children those for whom an organic etiology is present have lead burdens lower than in those for whom no apparent cause could be found. These data lead us to reject the notion that hyperactivity per se is responsible for the acquisition of elevated lead levels, and further strengthen the suspicion that for some children lower lead level absorption may be implicated in the development of the hyperkinetic disorder.This work was supported in part by the Office of Child Development, Grant #OCD-CB482. We thank Dr. Bernard Davidow for blood and urine determinations done by the Bureau of Laboratories, Lead Poison Division, Public Health Service, New York City. We also wish to thank Merck, Sharpe and Dohme for supplying the penicillamine for this study.     

Malleability of implicit associations across development

The prevalence of implicit intergroup bias in adults underscores the importance of knowing when during development such biases are most amenable to change. Although research suggests that implicit intergroup bias undergoes little change across development, no studies have directly examined whether developmental differences exist in the capacity for novel implicit associations to form or change. The present study examined this issue among children ages 5–12. Results from over 800 children provided evidence that novel implicit associations formed quickly, regardless of child age, association type (evaluative or non‐evaluative) or the target of the association (social or non‐social). Moreover, the magnitude of these changes was comparable across conditions. Coupled with similar findings among adults, these data underscore the importance of first impressions in shaping implicit intergroup bias and provide further evidence that the acquisition of implicit associations is governed by a domain‐general mechanism that may be fully in place by age 5.     

Autonomic responsivity during visual search of hyperactive and reading-disabled children

Heart rate and skin conductance measures, recorded during a visual search task, were compared for hyperactive, reading-disabled, hyperactive reading-disabled, and control elementary school boys. As shown in past work, basal autonomic levels did not statistically differentiate groups. In all groups, heart rate levels increased with task complexity, but more so on reward than on nonreward trials. In the intertriai interval, heart rate decelerated consistently when subjects were anticipating stimuli associated with reward, but when reward was uncertain, heart rate accelerated slightly or stayed the same. Control subjects exhibited anticipatory heart rate deceleration more consistently than did clinical subjects, especially the solely hyperactive ones. Skin conductance levels first decreased, then rose as task complexity increased, but the groups did not differ on this measure. A conditioning model is outlined to explain directional changes in heart rate.