Similar stimulus features control visual classification in orangutans and rhesus monkeys

Many species classify images according to visual attributes. In pigeons, local features may disproportionately control classification, whereas in primates global features may exert greater control. In the absence of explicitly comparative studies, in which different species are tested with the same stimuli under similar conditions, it is not possible to determine how much of the variation in the control of classification is due to species differences and how much is due to differences in the stimuli, training, or testing conditions. We tested rhesus monkeys (Macaca mulatta) and orangutans (Pongo pygmaeus and Pongo abelii) in identical tests in which images were modified to determine which stimulus features controlled classification. Monkeys and orangutans were trained to classify full color images of birds, fish, flowers, and people; they were later given generalization tests in which images were novel, black and white, black and white line drawings, or scrambled. Classification in these primate species was controlled by multiple stimulus attributes, both global and local, and the species behaved similarly.     

Cortical Networks for Correcting Errors in Sensorimotor Synchronization Depend on the Direction of Asynchrony

Recent work provides clues that different cortical mechanisms may be employed when correcting for errors in sensorimotor synchronization that increase tap-tone asynchrony compared with those that decrease it. The authors tested this hypothesis by recording 64-channel electroencephalography while participants synchronized with an auditory metronome. We systematically introduced positive and negative phase-shift perturbations that were either liminal (10%) and subliminal (3%). We used a distributed source modeling approach to evaluate oscillatory activity and connectivity of discrete cortical sources. Three key findings support our hypothesis. First was a theta band response indicative of error detection and top-down control observed in frontomedial presupplementary motor area (pre-SMA) and anterior cingulate for liminal positive perturbations. Second was an increase in theta band coupling between the SMA and contralateral motor cortex exclusively for positive perturbations suggesting a top-down modulation of motor parameters. Third, when compared with other conditions, liminal positive perturbations result in an increase in postmovement beta rebound within contralateral primary motor cortex. The authors propose that frontomedial motor areas exert a top-down inhibitory influence over the primary motor cortex to effectively lengthen tap intervals in response to lengthening tap-tone asynchronies.     

Leading God’s People: Perceptions of Influence Among African–American Pastors

Journal of Religion and Health - Religious leaders, particularly African–American pastors, are believed to play a key role in addressing health disparities. Despite the role...     

Extremes of self-esteem and narcissism and the experience and expression of anger and aggression

This study examined the level of self-esteem and narcissism as personality variables involved in the disposition to experience and express anger. Three hundred thirty-eight subjects were sampled across two higher education centres and one student teaching programme in the United Kingdom. It was reasoned that individuals with both high self-esteem and narcissism would report especially high tendencies to experience and express anger and aggression and that those with high self-esteem and low narcissism would report the lowest. These predictions were influenced by theories that emphasise the role of threats to high self-esteem in the production of aggression and violence. Results indicate that groups defined by their extreme scores on self-esteem and narcissism scales produced levels of anger expression in the predicted direction. The importance of considering extreme levels of self-esteem and narcissism (in conjunction with other factors) in an analysis of anger is discussed with reference to currently influential theories in the field. Aggr. Behav. 24:421–438, 1998. © 1998 Wiley-Liss, Inc.     

A Developmental Meta-Analysis of Peer Conflict Resolution

A series of meta-analyses examine developmental trends in peer conflict resolution. Peer conflict resolutions are most likely to involve negotiation, with coercion and then disengagement the next most likely strategies. Patterns of conflict resolution differ with age. Coercion is common among children and disengagement is rare. Negotiation is prevalent among adolescents and young adults; the former do not differ in terms of coercion and disengagement, whereas the latter tend to avoid coercion in favor of disengagement. Conflict resolutions also vary as a function of peer relationships, assessment procedures, and reporters. Negotiation prevails in all peer relationships except those with siblings; there is more negotiation among romantic partners than among friends, and more negotiation among friends than among acquaintances. Negotiation is the overwhelming strategy of choice for those presented with hypothetical disputes, but actual conflicts tend to be resolved by coercion. Observers indicate that most conflicts involve coercive resolutions, in contrast to self-reports, which suggest that negotiation prevails. Although conclusions are qualified by the limited number of studies available, follow-up moderator analyses indicate that negotiation increases and coercion declines with age across most peer relationships, assessment procedures, and reporters such that different patterns of conflict resolution during childhood give way to the same relative ordering of strategies during young adulthood.