Effects of luminance change in preview search: Offsets and onsets can be concurrently prioritized but not in isolation

Two experiments are performed to investigate how luminance change contributes to prioritized selection of new over old elements. Experiment 1 demonstrates that observers prioritize items that undergo a luminance change irrespective of the direction of that change. Experiment 2 shows that foreknowledge concerning the direction of luminance change signaling the target does not allow observers to prioritize the selection of luminance onsets over offsets and vice versa. The results suggest that prioritized selection of new over old elements is mediated by a general mechanism that is sensitive to luminance change, irrespective of its direction.     

African Philosophy and the Universalist Thesis

This article examines the contention, frequently defended by contemporary African philosophers, that philosophy is universal. Examples of the thesis are cited; various interpretations of its meaning are analyzed; and arguments against it by other African philosophers are presented. The article argues that the universalist thesis, however interpreted, contributes nothing to African philosophy and should be abandoned.     

CHRONIC SOCIAL STRESS, AFFILIATION, AND CELLULAR IMMUNE RESPONSE IN NONHUMAN PRIMATES

Abstract ——We report the first experimental study of the effect of long–term (over 2 years) exposure to a stressor on cellular immune response Forty–three male cynomolgus monkeys were randomly assigned to stable or unstable social conditions for 26 months The proportion of time spent in affiliative behaviors was assessed by observations made twice weekly T–cell immune response (mitogen–stimulated cell proliferation) was assessed weekly for 3 weeks immediately following the 26–month manipulation The possibility that affiliative behavior represents an attempt to cope with social stress was supported by greater affiliation among animals m the unstable condition than in the stable condition Animals in the unstable condition also demonstrated relatively suppressed immune response More affiliative animals showed enhanced immune response, with the beneficial effects of affiliation occurring primarily among unstable animals The data are interpreted as consistent with the stress–buffering hypothesis, that IS, affiliation protects animals from the potentially pathogenic influences of chronic social stress