Dissociating viewpoint costs in mental rotation and object recognition

In a mental rotation task, participants must determine whether two stimuli match when one undergoes a rotation in 3-D space relative to the other. The key evidence for mental rotation is the finding of a linear increase in response times as objects are rotated farther apart. This signature increase in response times is also found in recognition of rotated objects, which has led many theorists to postulate mental rotation as a key transformational procedure in object recognition. We compared mental rotation and object recognition in tasks that used the same stimuli and presentation conditions and found that, whereas mental rotation costs increased relatively linearly with rotation, object recognition costs increased only over small rotations. Taken in conjunction with a recent brain imaging study, this dissociation in behavioral performance suggests that object recognition is based on matching of image features rather than on 3-D mental transformations.     

Lateralized scratching in chimpanzees (Pan troglodytes): Evidence of a functional asymmetry during arousal

This study evaluated laterality in scratching by chimpanzees (n = 89) during socially arousing circumstances. Hand use and the side of the body scratched was recorded during a baseline and experimental condition. In the experimental condition, chimpanzees were shown a video of other conspecifics sharing, fighting over, and consuming a watermelon. Self-touches were categorized as either rubs or scratches. The chimpanzees showed a significant right hand bias for rubbing and also significantly directed the rubs to the right side of the body. For scratching, the chimpanzees showed no hand preference but a significant bias for scratching on the left side of the body. These results support the view that the right hemisphere regulates the autonomic nervous system during arousal.     

Amygdalectomy and responsiveness to novelty in rhesus monkeys (Macaca mulatta): generality and individual consistency of effects

Rhesus monkeys (Macaca mulatta) with bilateral ibotenic acid-produced lesions of the amygdala were compared with controls in several novel situations, including exposures to metal objects, toy animals, and a person. Early in testing, the monkeys with lesions showed reduced inhibitions on responsiveness compared with controls. With continuing exposures, differences between groups diminished sharply as inhibitions waned in the controls. This outcome is consistent with the hypothesis that the amygdala mediates caution in initial reactions to ambiguous or threatening novel situations, which, in the absence of adverse consequences, diminishes with repetition. Consistency of individual responsiveness across different situations, including pairing with other monkeys, was substantial in lesioned and normal monkeys, suggesting that stable qualities of temperament influenced the results in both groups.     

Does anhedonia in schizophrenia reflect faulty memory for subjectively experienced emotions?

The authors evaluated whether self-reported trait anhedonia in schizophrenia reflects faulty memory, such that patients are capable of experiencing pleasure while engaged in enjoyable activities but underestimate their pleasure in recalling these experiences. Thirty schizophrenia patients and 31 nonpatient control participants rated their emotional responses to pleasant and neutral foods and film clips and completed a surprise recall task for their emotions after a 4-hr delay. Despite reporting elevated trait anhedonia, patients did not significantly differ from control participants in immediate pleasant emotional responses to the stimuli or in delayed recall for these experiences. In-the-moment pleasure and short-term retention for emotional experiences thus appear to be relatively intact in schizophrenia. Alternative explanations for the hedonic deficit in this disorder are discussed.     

Examining the principles in principled conservatism: the role of responsibility stereotypes as cues for deservingness in racial policy decisions

Why do educated conservatives oppose affirmative action? Those in the "principled conservatism" camp say opposition is based on principled judgments of fairness about the policies. Others, however, argue that opposition is based on racism. The present article offers an alternative perspective that may reconcile these contradictory points of view. In 2 studies, the authors show 2 major findings: (a) that conservatives oppose affirmative action more for Blacks than for other groups, in this case women, and (b) that the relationship between conservatism and affirmative action attitudes is mediated best by group-based stereotypes that offer deservingness information and not by other potential mediators like old-fashioned racism or the perceived threat that affirmative action poses to oneself. The authors conclude that educated conservatives are indeed principled in their opposition to affirmative action, but those principles are group based not policy based.     

Native Americans and alcohol: past, present, and future

Native Americans have higher rates of alcohol use, frequency of use, and increased rates of fetal alcohol syndrome, compared with other ethnic groups (J. Hisnanick, 1992; P. A. May, 1996; J. M. Wallace et al., 2003). High prevalence rates of alcohol misuse among Native Americans must be understood in light of their unique history, which has resulted in trauma and exposure to many risk factors for problem alcohol use. Many risk factors have been identified in the general population; however, only some of these risk factors have been examined among Native American populations. The unique history and world view of Native Americans mean that, often, risk factors operate differently from the way they do in other populations. The authors discuss interventions and promising treatments.