Hemispheric specialization for speech in retarded children.

Hemispheric asymmetries in retarded and normal children were examined in dichotic tests which followed extensive auditory-discrimination training and which required non-verbal responses to digits or words. Mean right-ear advantages were smaller for the retarded group than for the normal group. However, most retarded children individually showed clear right- or left-ear advantages and absolute ear advantages were similar for the two groups. These data suggest atypical, but not reduced, functional asymmetries for retarded children.

Mental rotation and visual laterality in normal and reading disabled children.

Normal and reading disabled children, aged from 11 to 13 years and matched for I.Q., were timed as they discriminated bs from ds. When the letters were presented only in their normal upright orientations, normal readers responded more quickly when they were presented in the right than in the left visual hemifield, while the disabled readers showed a slight but insignificant left hemifield advantage. When the letters were presented in varying angular orientations the reaction times indicated that both groups "mentally rotated" an internal representation of each letter to the upright in order to discriminate them. The two groups did not differ in the accuracy of discrimination or in the estimated rate of mental rotation, and there were no significant hemifield differences in this phase of the experiment. These data offer no support for the view that disabled readers are deficient in spatial ability, but confirm earlier evidence that they may suffer a lack of left-hemispheric specialization.

Self-hypnosis in chronic pain. A multiple baseline study of five highly hypnotisable subjects.

The efficacy of self-hypnosis in the treatment of chronic pain was evaluated using a multiple baseline design for five patients referred to the Auckland Hospital Pain Clinic. Subjects were selected for high hypnotisability using the Stanford Hypnotic Clinical Scale. Daily records of pain intensity, sleep quality, medication requirements, and self-hypnosis practice were completed. At four research interviews the Health Locus of Control survey, the McGill Pain Questionnaire, and the Illness Self Concept Repertory Grid (ISCRG) were administered. Subjects also reported on daily activities and quality of life. Postal follow-up assessment occurred after 2 years. Two subjects reported overall improvement, two demonstrated little change in condition, although self-hypnosis was effective on some occasions, and one subject experienced deterioration in her condition. The patients showed an increase in personal locus of control and a shift of self-concept away from physical illness on the ISCRG. The results suggest that self-hypnosis can be a highly effective technique for some patients with chronic pain but not for all. Selection criteria and clinical factors other than hypnotisability need to be considered in further research, since even highly hypnotisable subjects may derive limited benefit from self-hypnosis.

Relationship between the delay task and rating scale measures of inattention and hyperactivity.

A group of 187 elementary school children were administered a microcomputer version of the Delay Task (Gordon, 1979) in which responses were reinforced only when they followed the preceding response by at least 6 seconds. They were also rated on the Conners Teacher Rating Scale (CTRS) by their classroom teacher. Performance on the Delay Task was not correlated with any of the CTRS subscales for the overall sample. Sex differences were found in the Conduct, Inattention, and Hyperactivity factors of the CTRS. No sex difference was found for performance on the Delay Task. When performance on the Delay Task was correlated with the four CTRS factors by sex, correlations between the Delay Task and the inattention subscale and hyperactive subscale were significant only for the male subsample. Implications of the findings for assessment of hyperactivity are discussed.

Performance of disabled and normal readers on the Continuous Performance Test.

Twelve-year-old reading-disabled children of normal intelligence were compared on the Continuous Performance Test with two control groups of normal intelligence and reading ability either of the same age or of the same reading age as the reading-disabled group. Signal-detection analysis showed that the reading-disabled were more conservative than chronological-age controls in their willingness to identify the target letter sequence. Although this conservative performance was shared by the reading-age controls, the reading-disabled suffered an additional handicap of relatively frequent anticipatory errors. Groups also differed on a sensitivity measure, suggesting a deficit in working memory in the reading-disabled children.

The effects of amount of training per reversal on successive reversals of a color discrimination.

Three groups of pigeons were trained on a red-green discrimination in which the stimuli were alternately presented in a multiple schedule of reinforcement. The discrimination was reversed 24 times. Groups were given 1, 2, or 4 hr of training on each discrimination. Increasing the length of training had two principal effects on reversal performance: it increased the rate of extinction of responding to one of the stimuli and increased the rate of reacquisition of responding to the other. The latter effect involved both an increase in reacquisition of responding to a positive stimulus within reversals and an increase in recovery of responding to the previous negative stimulus between reversals. Improvements in performance of each group over the series of reversals were qualitatively similar to the two effects of length of training on each discrimination, and were analogous to effects obtained in other studies involving overtraining and successive reversals of simultaneous discriminations.

Attentional changes during discrimination learning by retarded children.

Eight moderately retarded children were trained on a simultaneous two-choice discrimination problem and a series of discrimination-shift problems. The procedure required the subjects to perform overt observing responses to produce elements of the discriminative stimuli, making it possible to measure directly changes in attention to different aspects of stimuli during learning. The patterns of change in observing responses were generally in line with descriptions of attentional changes derived from two-process theories of discrimination learning; for example, the frequency of irrelevant observing responses was high during the presolution period during extradimensional shifts but was low during intradimensional shifts. Contrary to current theories, extradimensional shifts caused an immediate increase in irrelevant observing responses, and intradimensional shifts usually caused an increase in relevant observing responses. Subjects responded to later shift problems by initially increasing both relevant and irrelevant observing responses, then withholding irrelevant observing responses.

Response summation to a compound stimulus in a context of choice.

Key pecks by two groups of pigeons were reinforced on concurrent schedules. For group E, pecks were reinforced during either a visual or an auditory stimulus; for group E, an additional, extinction component was available, during which both visual and auditory stimuli were absent. After training, both groups were given a compound test to measure preference among four stimuli, the three used in training plus a compound of the visual and auditory stimulus. Group E showed preference for the compound, emitting more pecks and spending more time in this stimulus than in other stimuli. Group E showed no preference between the compound and visual stimulus, nor between the auditory stimulus and the absence of both stimuli, but preferred the former pair over the latter pair of stimuli.

Stimulus duration as a measure of stimulus generalization.

Four pigeons in the line-positive group were trained with a vertical line on a green background that signalled intermittent reinforcement while a plain green field signalled extinction. Four pigeons in the line-negative group were trained with the opposite discrimination. Response to a control key terminated any trial and initiated the next trial. The birds also used the control key during generalization tests to control the durations of trials in which various line orientations were presented. These durations were summed to provide generalization gradients of stimulus duration that were positive or negative in accordance with the trained discriminations. In Experiment 2, birds from the line-positive group were tested with a procedure in which the control key was not available on some trials. This provided an independent assessment of response rates to the test stimuli. These rates were used to predict the stimulus durations obtained when the control key was available. The findings supported a general model for the prediction of response distributions among concurrent stimuli from rates observed with single stimuli.

Inhibitory stimulus control in concurrent schedules.

Six pigeons were exposed to two keys, a main key and a changeover key. Pecking the main key was reinforced on a variable-interval 5-min schedule when the key was blue and never reinforced when the key displayed a vertical line on a blue background. Each peck on the changeover key changed the stimulus displayed on the main key. Each subject was given two generalization tests, consisting of presentations on the main key of six orientations of the line on the blue background, with no reinforcements being given. In one test changeover-key pecks changed the stimulus; in the other test the changeover key was covered and the experimenter controlled stimulus changes. Both responses to the six stimuli and time spent in the presence of the stimuli gave U-shaped gradients when the changeover key was operative. With most subjects, absolute rates of responding to each stimulus produced unsystematic gradients, whether or not the changeover key was operative.

Peak shift in concurrent schedules.

Pigeons were exposed to two keys, a main key and a changeover key. Initially non-differential training was given in which pecking the main key was reinforced on a variable-interval 2-min schedule when the key displayed the first stimulus, a black line on a blue background, and was reinforced on an identical but independent variable-interval 2-min schedule when the key displayed a plain blue stimulus. Later, differential training was given in which pecking the main key was reinforced on a variable-interval 2-min schedule when the first stimulus was displayed; and was reinforced on a variable-interval 10-min schedule when a second stimulus, a black line of another orientation on a blue background, was displayed. During non-differential and differential training, each peck on the changeover key changed the stimulus on the main key. Generalization tests were given before and after the differential training. These consisted of presentations on the main key of seven orientations of the black line on the blue background, including the first and second stimuli, with no reinforcements being given. Changeover-key pecks changed the stimuli on the main key. Generalization gradients were obtained using three measures: time spent, responses, and response rate in the presence of each test stimulus. Typically, maximum values on these measures occurred to stimuli away from the first in a direction opposite the second stimulus, and minimum values occurred to stimuli away from the second in a direction opposite the first.

The control of switching into blackout during extinction.

During the extinction component of a multiple variable-interval extinction schedule, four pigeons learned to peck a second key that switched off the keylights. Two experiments attempted to isolate the events that control this behavior. In the first experiment, switching into blackout was equally maintained when switches were restricted to the first minute as when they were restricted to the last minute of the extinction component. When switches could be emitted in the first and last minutes, they occurred more frequently in the first. Restricting switching to the first minute of each component and eliminating the blackout between components had no effect on switching. In the second experiment, when the stimulus correlated with extinction was omitted, switching decreased slightly. Omission of both multiple schedule stimuli decreased the switching rate, but switching was still maintained. Food reinforcement was then omitted and switching by two birds increased. Switching ceased when blackout was no longer the consequence of pecking the switching key. It was concluded that switching was not controlled by the similarity of the blackouts produced by the switching key and those that occurred between components; nor was it maintained by the temporal proximity of switching responses to the onset of the reinforced component. Finally, switching did not appear to be controlled by the main-key stimuli correlated with the components of the multiple schedule.

Effects of lorazepam on hyperactivity in ratarded children.

Seven mentally-retarded children, diagnosed as hyperactive, participated in a double-blind trial of the drug lorazepam (Ativan). Statistical analysis of the behavioural records showed that hyperactivity was typically greater during lorazepam than during placebo periods. The degree of hyperactivity was not systematically related to dosage level. The drug is therefore contraindicated for the control of hyperactivity in mentally retarded children.

The balance model of dyslexia and remedial training: an evaluative study.

The aim of this study was to test the validity of Bakker's (1983, 1990) theory and treatment paradigm of dyslexia. Twenty-one children (mean age = 9.9 years) categorized as P-type dyslexics (showing accurate but slow and fragmented reading) and 19 children (mean age = 9.7 years) categorized as L-type dyslexics (fast but inaccurate readers) were presented with hemisphere-specific stimulation (HSS) and hemisphere-alluding stimulation (HAS). HSS was produced by presenting words to either the left or the right visual half-field, or to the left or right hand of the participant. HAS training was achieved through the presentation of either semantically/phonetically demanding or perceptually demanding text. Participants were given either a treatment program that was specifically designed for their particular dyslexia subtype, or a program that had been deliberately chosen to be inconsistent with their subtype. Contrary to predictions, participants made gains on all of the reading measures, regardless of the type of treatment given. On the basis of these findings it is suggested that treatment gains made are due to nonspecific training effects and not to the specific nature of Bakker's remedial strategies.

The representativeness of observational samples of different durations.

The representativeness of behavioral observation samples with durations of less than the whole time of interest was investigated. A real-time recording system was developed to quantify the behavior of 5 profoundly mentally retarded physically handicapped adult students in an institutional training setting. Behavior was observed using six mutually exclusive and exhaustive categories during 2.5-hr observation sessions. Sample observation sessions with durations ranging from 15 to 135 min were computer simulated from the whole-session (150-min) records. It was found that the representativeness of these samples, when compared to whole-session records, was a function of the relative duration of the behavioral categories and of sample duration. The occurrence of relatively high-duration behaviors (lasting for more than 50% of the session) was estimated to within 20% error by samples of less than 60 min, but low-duration behaviors (1 to 3% of the session) were inadequately quantified even from 135-min samples. Increasing irregularity of bouts of behavior in the low-duration behaviors is suggested as the cause of the functions obtained. Implications of the findings for applied behavior analysis are discussed, with the recommendation that the adequacy of observational session durations be empirically assessed routinely.

The naming of disoriented letters by normal and reading-disabled children.

Normal and reading-disabled children, 11-13 years old, named the letters F, G and R, presented in normal and backward versions, in varying angular orientations, in left and right visual fields. Both groups were faster at naming the normal than the backward letters, even though mental rotation was evidently not required. The results also offered no support for Orton's theory concerning the interrelations between mirror-image equivalence, hemispheric differences and reading disability. The only measures unrelated to reading itself that discriminated the groups were digit span and a special difficulty among the disabled readers in naming the letter G.

Psychological effects of chronic exposure to 50 Hz magnetic fields in humans living near extra-high-voltage transmission lines.

The validity of several published investigations of the possibility that residential exposures to 50 Hz or 60 Hz electromagnetic fields might cause adverse psychological effects, such as suicide and depression, may have been limited by inadequate controlling for confounders or inadequate measurement of exposures. We investigated the relationships between magnetic field exposure and psychological and mental health variables while controlling for potential confounders and careful characterising individual magnetic field exposures. Five-hundred-and-forty adults living near transmission lines completed neuropsychological tests in major domains of memory and attentional functioning, mental health rating scales and other questionnaires. Magnetic field measurements were taken in each room occupied for at least one hour per day to provide an estimate of total-time-integrated exposure. The data were subjected to joint multivariate multiple regression analysis to test for a linear relation between field exposure and dependent variables, while controlling for effects of possible confounders. Performance on most memory and attention measures was unrelated to exposure, but significant linear dose-response relationships were found between exposure and some psychological and mental health variables. In particular, higher time-integrated exposure was associated with poorer coding-test performance and more adverse psychiatric symptomatology. These associations were found to be independent of participants' beliefs about effects of electromagnetic fields.