Risk Factors for Infant Abuse and Neglect in Group-Living Rhesus Monkeys

This study investigated maternal abuse and neglect of offspring in a large population of rhesus monkeys over a period of 29 years. Abuse and neglect did not occur together and were associated with different risk factors. Infant abuse was concentrated in 8 of 57 families and among closely related females. Abuse was also repeated with successive offspring. In contrast, infant neglect was not affected by genealogical factors, was not repeated with successive offspring, and was displayed mostly by primiparous mothers. These results suggest that abuse and neglect may be different phenomena and that infant abuse in group-living monkeys could represent a good animal model for investigating the mechanisms underlying the intergenerational transmission of child maltreatment.     

What motivates stunt men?

If confrontation with danger is related to fear, and fear is considered to be the motivation for avoidance behavior, the question remains why certain people seek confrontations with danger. The present study, part of a larger one, is concerned with confrontation with actual danger, as in dangerous sports or voluntarily chosen dangerous professions. It reports the results of interviews with six stunt men. These results partly support the hypothesis of Zuckerman on sensation-seeking personality features: The subjects appear to be eager for varied experience and relatively unconcerned with negative consequences of their actions. The ability to stand the strains and to concentrate under riskful conditions shows up as a further important characteristic of stunt men. The major reward that constitutes the motivation for engaging in the stunting profession appears to consist of being able to meet the challenges involved, with increased self-esteem, receiving acclaim, and monetary profit as secondary rewards. Ability and motivation thus are inextricably intertwined.With acknowledgment to Prof. Nico Frijda, without whose support this article would not have been written and would not have acquired its present form.     

Iterated N-player prisoner's dilemma games

Philosophical Studies -     

Representational guidance of action production in observational learning: a causal analysis

This experiment tested the hypothesis that the number of model presentations and verbal coding of modeled actions affect reproduction accuracy through their effect on cognitive representation. Subjects viewed a complex action pattern either two or eight times with or without verbal coding to highlight the dynamic structure of the component actions and their temporal sequencing. They then received, in order, a recognition test and a pictorial-arrangement test to assess the accuracy of their cognitive representations of the modeled actions. Subsequently, all subjects were tested for their ability to reproduce the action pattern from memory. Results showed that increased exposure to modeled actions enhanced the accuracy of both the cognitive representation and the behavioral reproduction. Verbal coding also increased cognitive and reproduction accuracy, but only when combined with multiple opportunities to observe the modeled actions. A causal analysis confirmed that the effects of multiple exposures and verbal coding were entirely mediated by changes produced in the accuracy of cognitive representation.     

A psychiatrist's reflections on the workers' compensation system

In the ‘looking-glass land’ of workers' compensation psychiatry, symptoms are not always what they seem, treatments may have little or no positive effect, and workers' claims of continued disability may puzzle and perplex. Disability is in part a social role, and a simple medical model cannot explain the complex interactions of sociology, psychology, anthropology, medicine, economics, and law characteristic of the workers' compensation system. Psychiatrists functioning within and reciprocally shaped by this semi-adversarial system will rarely encounter an ‘ideal’ patient. Factors in all areas of workers' lives, including those integral to the workers' compensation system, influence their movement along a health-illness, ableddisabled axis. This paper identifies a number of interacting factors that may prolong, or even subvert, the recovery process following a work-incurred injury or illness.     

Simple software for impedance cardiography

Simple software techniques for the digital analysis of impedance cardiography data are described. The software digitizes simultaneous impedance and ECG signals, averages these signals over time on a beat-by-beat basis, processes the averaged signals to locate relevant features, and computes heart rate, stroke volume, and cardiac output for the averaged period. The source and executable code, written in Pascal for a PDP-11 with standard peripheral addressing and a VT125 graphics terminal, is available from the authors.     

When and Why Mimicry is Facilitated and Attenuated

Although people tend to mimic others automatically, mimicry is facilitated or attenuated depending on the specific context. In the current paper, the authors discuss when mimicry is facilitated and attenuated depending on characteristics of situations, targets, and observers. On the basis of the review, the authors propose a new model – the Associated Reactions to Actions in Context model (ARAC) – to explain why and when mimicry is facilitated and attenuated. ARAC proposes that when people observe an action, reaction‐to‐action neurons fire. Which reaction is elicited depends on the (learned or innate) association with an action in that context. Thus, when mimicry is rewarding in a specific context, this response is facilitated. When mimicry is damaging, this response is attenuated, and another reaction may be facilitated instead. The authors discuss the added value of the ARAC model compared to other models explaining the elicitation of behavioral reactions.     

Courting on the beach: how team position implicitly influences decision-making in beach volleyball serves

Masters, van der Kamp, and Jackson [2007. Imperceptibly off-centre goalkeepers influence penalty-kick direction in soccer. Psychological Science, 18, 222–223] demonstrated that a goalkeeper in soccer penalty kicking standing marginally to one side of the goal’s centre unconsciously influences a penalty takers’ goal side selection. In two experiments, we examined whether the positions of the receiving players in beach volleyball affect a player’s decision to what area of court to play. Both experiments differed in the degree of attention participants directed to the largest court area. Results showed that participants made decisions favouring the larger court area although they were unaware of the receivers’ asymmetrical positioning. This effect was more pronounced in Experiment 1, suggesting that the degree to which attention is directed to the critical information (i.e. largest court area) can be considered an important moderator. These observations indicate that implicit effects of positioning reflect a more general phenomenon in and outside of sports that can be exploited for improving chances of success.