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.     

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.     

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.     

Dextroamphetamine and placebo practice effects on selective attention in hyperactive children

Three groups of three boys referred to a hospital study unit for evaluation of hyperactive behavior were tested on a classification task involving selective attention while on either dextroamphetamine (D) or placebo (P). In two sessions, groups had D first, P second (DP), or PD, or PP. Amphetamine reduces response times in general and reduces interference due to orthogonally varying irrelevant information. Practice while on placebo improves performance in a subsequent placebo session. Practice while on amphetamine does not, however, improve performance in the subsequent session on placebo. Assessment of the extent of the drug-state-related practice effect is necessary for evaluation of long-term benefits of dextroamphetamine therapy in these children.Thanks go to Ramona Roberts for assistance in running subjects. The University of Maryland Computer Science Center provided the computer facilities for data analysis.     

Visual and auditory attention performance in hyperactive children: Competence or compliance

The effect of self-control and compliance on the attentional performance of hyperactive children was assessed. Visual and auditory attention tasks were presented in conditions in which the experimenter was either absent and therefore not imposing external control, or present and therefore imposing some degree of control. There was no difference in performance between hyperactives and controls when the experimenter was present, but the hyperactives' performance showed a greater deterioration than controls when the experimenter was absent. The amount of movement displayed during the tasks was greater for hyperactives and increased more for this group during experimenter-absent conditions. The results support the contention that noncompliance is a major contributor to the poor performance of hyperactive children, which can be seen as an application deficit rather than an ability deficit. These findings have relevance for the current debate on the association between hyperactivity and conduct disorder, and from an applied perspective they serve to stress the importance of situational contributors to the problem behaviors of hyperactive children.     

Effects of methylphenidate (Ritalin) on selective attention in hyperactive children

This study investigated the effect of methylphenidate (Ritalin) on the selective attention of hyperactive children designated as favorable or adverse responders to stimulant medication. Using a type II incidental learning paradigm, it was found that children in the drug condition recalled more central and less incidental stimuli than those children in the placebo condition. While no differential effects on recall were found for responder type, methylphenidate did affect the spontaneous overt labeling of central stimuli by the favorable responder group. Results were interpreted in terms of the role of methylphenidate in narrowing the focus of attention. Implications for the classification of hyperactive children as favorable and adverse responders were also discussed.This paper is based on a master's thesis completed by the first author in the Department of Psychology, University of Guelph, under the supervision of the second author. The authors wish to thank J. Thomas Dalby for his assistance in the conducting of this experiment.     

Focused attention in three-dimensional space

The size of focused attention was assessed within a three-dimensional display. Subjects viewed random-dot stereogram displays in which they responded differentially to vertical and horizontal bars. Adjacent noise elements either were identical to the response target or specified the opposite response. The position of the noise elements was varied in depth according to binocular disparity. Interference by incompatible noise elements decreased with depth separation between the noise elements and response target. In addition, interference was greater for noise elements that were more distant from the observer than from the response target than it was for noise elements that were closer to the observer than to the response target. The implications of these results for a viewer-centered representation of focused attention in depth are discussed.     

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 and depressive deficits in memory.

Hertel and Rude (1991) investigated the effects of depression on memory for words in a sentence completion task. They found that depressive deficits in memory can be eliminated by procedures that increase depressed Ss' focused attention to the task. Three areas are considered in this article: irrelevant thoughts, distraction, and inhibition.     

Effects of event rate and display time on sustained attention in hyperactive,normal, and control children

Two experiments were conducted to determine whether hyperactive boys have a unique deficit in sustained attention. Groups with DSM-III diagnoses of attention deficit disorder (ADDH), conduct disorder (CD), ADDH+CD, and learning disorder were compared with normal controls on the Continuous Performance Task. In Experiment 1, stimulus presentation rate (stimulus onset asynchrony, SOA) and display time were varied to manipulate attentional demand, and speed and accuracy of performance were measured. The ADDH group was uniquely affected, with less accurate performance at the fastest and slowest SOA. To distinguish the effects of time on task and SOA, the duration of each SOA condition was held constant in Experiment 2. The poorer performance of the ADDH group at the fastest SOA was no longer evident. This finding indicates that the deficit of sustained attention in boys who have ADDH is associated with a greater susceptibility to refractory effects, which is influenced by practice.This research was supported by the Ontario Mental Health and Ruth Schwartz Foundations through a graduate fellowship awarded to P. Chee and a research grant to R. Schachar, G. Logan, and R. Wachsmuth. Dr. Schachar was also supported by the Canadian Psychiatric Research Foundation. This article is based, in part, on a doctoral dissertation submitted by the first author to the Ontario Institute for Studies in Education. The authors thank Dr. John Lovering and the staff of the Departments of Psychiatry and Psychology, The Hospital for Sick Children, for their cooperation in the conduct of this study. This paper was prepared with the assistance of the Medical Publications Department, The Hospital for Sick Children, Toronto.     

Attaining and maintaining preparation: A comparison of attention in hyperactive,normal, and disturbed control children

The hypothesis that hyperactive children have a deficit in sustained attention was investigated. Eighteen children who had attention deficit disorder with hyperactivity (ADDH), aged 7 to 11 years, were compared with children who had conduct disorder (n = 15), mixed conduct disorder and ADDH (n = 26), emotional disorder (n = 18), or learning disability (n = 22), and with normal controls (n = 15). The subjects were tested on three versions of the Continuous Performance Task. Sustained attention was assessed from performance with increasing time on task and from ability to prepare attention in response to a warning. Performance of all subjects deteriorated with increasing time and improved with the opportunity to prepare attention. Hyperactive subjects were not more adversely affected by increasing time, nor did they benefit less than controls from the opportunity to prepare attention. Data reanalysis after rediagnosis according to ICD-9 criteria did not change the results. This study did not confirm the hypothesis that hyperactive children have a unique sustained attention deficit.     

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.     

Focused and divided attention to dichotic wordstreams

Two dichotic wordstreams both containing meaningful word relations (synonyms) were presented under two different task requirements. When asked to attend to both channels, the majority of the subjects (8 out of 10) was able to pick up the synonyms in both wordstreams but, in the case of simultaneous (double) synonym occurence, dual performance became worse. The outcomes of the focused attention task corroborated the multi-channel input processing idea: synonyms on the to-be-rejected channel retarded, in particular, the identification of the synonyms on the to-be- attended channel. Consistent with the selective attention literature, although functioning in a suboptimal way, filter setting appears to work better when the subject is confronted with a longer string of words to which he must attend.     

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.