Accommodation to increased accuracy demands by the right and left hands

This study was designed to identify the phase of rapid aimed movements responsible for hand differences in motor skill, and to evaluate potential differences between the hands in accommodating to greater accuracy demands. In both experiments, an accelerometer mounted on a stylus allowed key changes in acceleration to be used to partition the movement into phases. In Experiment 1, slower left hand movement times were attributable primarily to a terminal homing-in phase, especially as target size decreased. Since error rates varied as a function of hand and target size, speed-accuracy trade-offs may have occurred. Experiment 2 rigidly controlled error rate and confirmed the major hand difference to occur in the latter phase of the movement where error correction is presumed. Although less pronounced, adjustments were made in the earlier movement phases as well. Accommodation to greater accuracy demands involved moving the stylus closer to the target before decelerating to engage in error correction. This adjustment to gain enhanced precision was more pronounced in the left hand.     

Antidepressant treatment of children: clinical relapse is unrelated to tricyclic plasma concentrations

Plasma concentrations of imipramine and amitriptyline and their desmethylated metabolites were measured in 20 children being treated for major depressive illness 2 wk. and 5 to 10 wk. after achieving drug dosages of 2.25 mg/kg body weight. At 2 wk. all children had exhibited clinical improvement, but by 10 wk. 4 of the 10 children treated with imipramine and 5 of the 10 children treated with amitriptyline had experienced clinical relapse of depressive symptoms. Tricyclic antidepressant plasma concentrations and ratios were comparable in the subgroups of children who maintained their clinical improvement and those who relapsed. There was no evidence of a systematic decline in plasma tricyclic antidepressant concentrations in those children who relapsed.     

Infant hypotonia, obesity, hypogenitalism and oligophrenia--new viewpoints on the etiology and symptoms of Prader-Willi syndrome

We present four cases of Prader-Willi syndrome. Two of them have an abnormality of a chromosome 15, the other both show different chromosomal abnormalities. Translocations or deletions were found recently in the bands 15q11/12 in about 60% of the cases of Prader-Willi syndrome. The consequences for diagnosis, symptomatology and genetic counselling of the syndrome are discussed.     

A logic of message and reply

In this paper we sketch a logic of message and reply. The logic is intended for application in a wide variety of situations, not restricted to the two-person, turn-taking situation. Each message has a body and a vector; the vector specifies the from, to, and the like. To reply to a message, it suffices to give either (1) a complete reply to the body or (2) a corrective reply to at least one presumption derivable from the vector. We discuss the problems of achieving effectiveness and completeness with respect to certain aspects of communication. The results are mixed. In section 9 we argue semi-formally that, in a certain sense, dialogue is necessary. Finally we note that this logic is not a rival of other approaches but may be combinable with them.     

Estimating social and nonsocial utility functions from ordinal data

This paper reports an experiment testing two hypotheses. The first is that the value or utility associated with a payment to one's self and a payment to a co-worker can be represented as an additive function of a utility for own payment (nonsocial utility) and a utility for the difference between own and other's payment (social utility). The second hypothesis is that changes in the amount of work accomplished by one's self and/or the other should influence the social, but not the the nonsocial utilities. Support for both hypotheses is reported.     

Syllogistic reasoning in varied narrative contexts: Aspects of logical and linguistic development

This experimental study examined the effects on syllogistic reasoning in grades 6 and 12 of certain contextual narrative variables. The experimental task consisted of 27 varied syllogistic problems based on information contained in three narrative texts—a fantasy passage, a realistic passage, and a contractual passage. Versions of these texts were constructed for each group reading level. Analysis of the data revealed several significant interactions between subject groups and treatment variables. In particular, younger subjects performed better than grade 12 subjects on problems following the fantasy narrative, while the older subjects did better with the other two passages. The results suggest that some orthodox views about concrete-versus formal-operational reasoning abilities and about the distinction between abstract and concrete materials need to be reassessed within a discourse-processing framework that is sensitive to the discourse worlds in which problems are embedded.The author wishes to acknowledge the support of an Isaak Walton Killam Doctoral Scholarship for this research.     

Self-labeling by educably mentally retarded high school students in their mainstream and special education classes

Educably mentally retarded (EMR) students and nonhandicapped students from their mainstream classes completed semantic differential ratings of a stereotypic popular teen-ager, juvenile delinquent, and special education student. Subjects also rated their global self-concepts and situation-specific self-concepts within the mainstream and the special class settings. Ratings were done at the beginning (Time 1) and the end (Time 2) of a semester. Results showed that mainstream classes did not "de-label" EMR students. Within the mainstream class, the number of EMR students who saw themselves as similar to a special education student significantly increased over time. Moreover, at Time 2, EMR students were more likely to think of themselves as similar to a special education student in their mainstream class than in their special education class. However, EMR subjects' global self-concepts did not change. Implications for mainstreaming are discussed.     

Continuous monitoring of human contingency judgment across trials

Recent evidence suggests that people are sensitive to the degree of contingency between their actions and ensuing outcomes, but little is known about the way in which such contingency judgments develop as more and more information about the contingency is provided. Three experiments examined this issue in the context of a video game. In Experiment 1, it was found that contingency judgments follow growth functions: When the contingency was positive, judgments increased toward a positive asymptote, and when the contingency was negative, judgments decreased toward a negative asymptote. When the contingency was zero, judgments themselves remained close to zero but were biased by the overall frequency with which the outcome occurred. In Experiment 2, it was shown that the growth function was not the result of the anchoring of early judgments at the zero point. The bias in judgments when the contingency is zero was investigated in Experiment 3. The results are discussed in terms of rule-based analyses and contemporary theories of conditioning.     

Changes in self-stimulatory behaviors with treatment

For four of six autistic children who underwent intensive behavioral treatment, the nature of their self-stimulatory behavior changed from initial lowlevel motor behaviors (such as rocking, spinning, twirling) to differing kinds of higher-level behaviors (such as lining of objects, echolalic speech, and preoccupation with spelling and numerical values). The children who changed to the highest levels of self-stimulatory behavior also showed the largest gains in treatment (as determined by IQ scores, school placement, etc.). The changes in self-stimulatory behaviors were attributed to the intense teaching of appropriate social behaviors and the explicit therapeutic suppression of low-level, self-stimulatory behaviors. The long-term therapeutic effects of changing from lower-to higher-level forms of self-stimulatory behavior were discussed.This study was supported by a grant from the National Institute of Mental Health (grant MH 11440). We want to express our thanks to the parents who allowed us to study their children. We gratefully acknowledge the assistance of Maria Audero with the design of the weighted measure, and Tracee Parker with the collection of the data.     

Stability and Change in Type A Components and Cardiovascular Reactivity in Medical Students During Periods of Academic Stress1

This study examined the effects of academic stress upon components of Type A behavior and cardiovascular reactivity. In a longitudinal design, heart rate and blood pressure responses to the Type A Structured Interview (SI) and additional laboratory challenges were measured in medical students at three points during an academic semester. Sessions 1 and 3 were scheduled during vacation periods; Session 2 took place during an intensive examination week. Results indicated that three “stylistic” components of Pattern A derived from the SI—loud and explosive speech, short response latency, and potential for hostility—increased significantly during the exam period. Similar increases achieved marginal significance for another stylistic component, rapid and accelerated speech. By contrast, global Type A assessments did not increase with academic demands. Cardiovascular reactivity was significantly but only moderately stable across the three sessions, showing less consistency than has been reported in previous research. In addition, there was little evidence in this study that cardiovascular reactivity was potentiated by academic stress or by Type A behavior. These results demonstrate the influence of naturalistic environmental factors on overt behavioral components that have recently been suggested as coronary risk factors. Therefore, it is advisable for future experimental and epidemiological research to examine the social and environmental context in which these behaviors occur.