Elevation and reduction of plasma tryptophan and their effects on aggression and perceptual sensitivity in normal males

Data from experimental animals suggest that 5-hydroxytryptamine (5HT) may have an inhibitory effect on aggression, while clinical studies have found a correlation between pathological aggression and low brain 5HT. To investigate this relationship further we used amino acid mixtures designed to raise or lower the levels of the 5HT precursor, tryptophan. Normal male subjects were given tryptophan-depleted, balanced, or tryptophan-supplemented ammo acid mixtures and tested for aggression 5 hours later. The balanced amino acid mixture served as a control for the tryptophan depletion and supplementation. Testing for aggression was done using the Buss paradigm in which subjects deliver electric shocks to a (nonexistent) partner in response to stimulus tones. Duration and intensity of shock delivered were the measures of aggression, while responsivity to the stimulus tones was the measure of perceptual sensitivity. Neither tryptophan supplementation nor tryptophan depletion had any effect on these measures of aggression or perceptual sensitivity. We conclude that raising or lowering the synthesis of brain 5HT through alterations in tryptophan availability does not influence aggression in normal males as measured by the Buss task.     

Perceived motion in structure from motion: Pointing responses to the axis of rotation

We investigated the ability to match finger orientation to the direction of the axis of rotation in structure-from-motion displays. Preliminary experiments verified that subjects could accurately use the index finger to report direction. The remainder of the experiments studied the perception of the axis of rotation from full rotations of a group of discrete points, the profiles of a rotating ellipsoid, and two views of a group of discrete points. Subjects’ responses were analyzed by decomposing the pointing responses into their slant and tilt components. Overall, the results indicated that subjects were sensitive to both slant and tilt. However, when the axis of rotation was near the viewing direction, subjects had difficulty reporting tilt with profiles and two views and showed a large bias in their slant judgments with two views and full rotations. These results are not entirely consistent with theoretical predictions. The results, particularly for two views, suggest that additional constraints are used by humans in the recovery of structure from motion.     

Forward inference in risky choice: Mapping gaze and decision processes

The study of cognitive processes is built on a close mapping between three components: overt gaze behavior, overt choice, and covert processes. To validate this overt–covert mapping in the domain of decision‐making, we collected eye‐movement data during decisions between risky gamble problems. Applying a forward inference paradigm, participants were instructed to use specific decision strategies to solve those gamble problems (maximizing expected values or applying different choice heuristics) during which gaze behavior was recorded. We revealed differences between overt behavior, as indicated by eye movements, and covert decision processes, instructed by the experimenter. However, our results show that the overt–covert mapping is for some eye‐movement measures not as close as expected by current decision theory, and hence question reverse inference as being prone to fallacies due to a violation of its prerequisite, that is, a close overt–covert mapping. We propose a framework to rehabilitate reverse inference.     

The Self‐Care of Psychologists and Mental Health Professionals: A Review and Practitioner Guide

It has been documented in the professional literature that psychologists and mental health professionals in general tend to neglect their own mental health, despite serving in a field that promotes the health and well‐being of others. Numerous empirical studies support the need for psychologists and mental health professionals to be more conscientious of the effect that stress and the nature of their work has on them. This article reviews some of the recent literature and discusses the pertinent issues at hand. A number of interventions are suggested along with tips for professionals to consider in order to function in a more productive and ethical fashion.     

On methods of reporting clinical material.

The members of the Committee on Scientific Activities of the American Psychoanalytic Association are concerned about the paucity of clinical data in psychoanalytic reports and by the quality of what does exist. We have proposed a few standards for clinical reports that we believe will be reliable and clear and will have enduring usefulness. We recognize the need for maintaining confidentiality and, at times, for disguise; we also recognize the need to balance these requirements against the dangers of misleading the reader (or listener). These conflicting requirements have resulted in our concentrating on some general principles for clinical reporting. We have appended a tentative form, and examples, to be considered for that purpose.     

Teachers' and mothers' assessment of children's behaviors from kindergarten to grade two: Stability and change within and across informants

Consistency between teachers' and parents' ratings of 229 children's prosocial and problem behaviors was investigated from kindergarten through grade two. Intrarater stability was also analyzed. Results indicated moderate but decreasing interrater agreement from kindergarten to grade two for boys on externalizing behaviors. Interrater agreement for the same behavior dimension for girls was moderate and stable, whereas it was low on internalizing behavior problems and prosocial behaviors, for both genders throughout the 3-year period. Moreover, difference between teachers' and parents' ratings of externalizing behaviors increased from kindergarten to grade two. Decreasing level of agreement through time appeared to be related to a reduction of teacher-rated externalizing behaviors not paralleled by a reduction in parent ratings. Analyses were also performed at the item level of the externalization scale to identify which specific behaviors were responsible for the increasing divergence in interrater agreement from kindergarten through grade two. Alternative interpretations were considered in order to account for present and past results. Implications for screening and assessment purposes were discussed.This research was supported by grants from the Social Sciences and Humanities Research Council of Canada and from Québec's Health Research Fund (FRSQ). We wish to thank the authorities and directors of the schools from the Val d'Or School Board as well as the kindergarten, first and second grade teachers, children, and parents for their collaboration. We also thank Lyse Desmarais-Gervais, Daniel Corriveau, Jean Desrosiers and Hélène Boileau for their participation in the data collection or analysis.     

A remote-controlled device for long-term blood collection from freely moving, socially housed animals

A remote-controlled device was developed for injection of fluids and collection of blood samples from freely moving, socially housed animals via an indwelling catheter. Samples are collected at times chosen by the investigator, and the animal is not aware that sampling is occurring. This technique allows measurement of plasma catecholamines and other substances that fluctuate rapidly, are affected by psychosocial stimuli, and are altered by capture and other stressful activities that often accompany sample collection. Rapid retrieval of samples is facilitated by remote-controlled injection of an anesthetic. The device has been used to collect blood from dominant and subordinate male baboons before and during events such as chases and presentation of food treats. Heart rate and blood pressure were measured via radio telemetry, and behavior was recorded on videotapes. This technique allowed construction of multifaceted physiological profiles of social roles and behaviors.