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751.
This study examined the development of infants' ability to perceive, learn, and remember the unique face-voice relations of unfamiliar adults. Infants of 2, 4, and 6 months were habituated to the faces and voices of 2 same-gender adults speaking and then received test trials where the faces and voices were synchronized yet mismatched. Results indicated that 4- and 6-month-olds, but not 2-month-olds, detected the change in face-voice pairings. Two-month-olds did, however, discriminate among the faces and voices in a control study. Results of a subsequent intermodal matching procedure indicated that only the 6-month-olds showed matching and memory for the face-voice relations. These findings suggest that infants' ability to detect the arbitrary relations between specific faces and voices of unfamiliar adults emerges between 2 and 4 months of age, whereas matching and memory for these relations emerges somewhat later, perhaps between 4 and 6 months of age.  相似文献   
752.
This study explores multiple relational contexts that promote vulnerability and protection against early pregnancy in a potential risk group of Portuguese adolescents. A comparative analysis was made between two groups of female adolescents of low socioeconomic status: pregnant adolescents (n=57) and adolescents without a history of pregnancy (n=81). Results suggest that several variables belonging to different contexts-family and school and peer relations--are important in the characterization of the two groups. Lower levels of mother's overprotection and father's emotional support, presence of early pregnancy in adolescent's mother, lower level of emotional proximity to peer relations, and higher number of school failures are significantly associated with adolescent pregnancy.  相似文献   
753.
Two studies investigated the impact of past ingroup experiences on individual aspirations and effort. Participants were told that in the past, members of their group had either been offered no opportunities (closed), few opportunities (token), or equal opportunities (open) to achieve a desired outcome. The results show that past group experiences determine responses to current opportunities and affect the perceived feasibility of individual success as well as individual performance. Exposure to a token system has different effects, depending on whether the group is historically advantaged or disadvantaged. Whereas those with a collective history of success see token mobility as a challenge and show superior performance, the same situation constitutes a threat to members of a historically disadvantaged group, who fail to take advantage of the opportunities offered to them and perform suboptimally.  相似文献   
754.
Current evidence appoints a central role to cholinergic interneurons in modulating striatal function. Recently, a long-term potentiation (LTP) of synaptic transmission has been reported to occur in these neurons. The relationship between the pattern of cortico/thalamostriatal fibers stimulation, the consequent changes in the intracellular calcium concentration ([Ca2+]i), and the induction of synaptic plasticity was investigated in striatal cholinergic interneurons from a rat corticostriatal slice preparation by means of combined electrophysiological intracellular recordings and microfluorometric techniques. Different protocols of stimulation were considered, varying both the frequency and the duration of the train of stimuli. High-frequency stimulation (HFS) (three trains at 100 Hz for 3 sec, 20-sec interval) induced a rise in [Ca2+]i, exceeding by fivefold the resting level, and caused a LTP of synaptic transmission. Tetanic stimulation delivered at lower frequencies (5-30 Hz) failed to induce long-term changes of synaptic efficacy. The observed elevation in [Ca2+]i during HFS was primarily mediated by L-type high-voltage activated (HVA)-Ca2+ channels, as it was fully prevented by nifedipine. Conversely, blockade of NMDA and AMPA glutamate receptor did not affect either LTP or the magnitude of the [Ca2+]i rise. Interestingly, the pharmacological analysis of the post-tetanic depolarizing postsynaptic potential (DPSP) revealed that LTP was attributable, to a large extent, to the potentiation of the GABA(A)-mediated component. In conclusion, the expression of LTP in striatal cholinergic interneurons is a selective response to a precise stimulation pattern of induction requiring a critical rise in [Ca2+]i.  相似文献   
755.
Following the September 2001 terrorist attacks on the United States, much support for torture interrogation of terrorists has emerged in the public forum, largely based on the “ticking bomb” scenario. Although deontological and virtue ethics provide incisive arguments against torture, they do not speak directly to scientists and government officials responsible for national security in a utilitarian framework. Drawing from criminology, organizational theory, social psychology, the historical record, and my interviews with military professionals, I assess the potential of an official U.S. program of torture interrogation from a practical perspective. The central element of program design is a sound causal model relating input to output. I explore three principal models of how torture interrogation leads to truth: the animal instinct model, the cognitive failure model, and the data processing model. These models show why torture interrogation fails overall as a counterterrorist tactic. They also expose the processes that lead from a precision torture interrogation program to breakdowns in key institutions—health care, biomedical research, police, judiciary, and military. The breakdowns evolve from institutional dynamics that are independent of the original moral rationale. The counterargument, of course, is that in a society destroyed by terrorism there will be nothing to repair. That is why the actual causal mechanism of torture interrogation in curtailing terrorism must be elucidated by utilitarians rather than presumed.  相似文献   
756.
A range of behavior-much deemed problematic by society-is treated with behavioral methods or psychotropic medications. Although the processes associated with behavioral interventions have been investigated using conceptual, experimental, and applied analyses, less is known about the behavioral processes associated with the use of psychotropic medication. Psychotropic drugs produce at least two types of effects of behavioral interest: (a) primary effects of drug action on target behaviors and (b) side effects that change the target or other behavior. Although an empirical literature exists regarding the former effects, little attention has been given to the latter topic. In this paper we offer a conceptual analysis of the side effects of psychotropic medication. We propose that the side effects of various drugs can influence behavior by functioning as motivating operations, conditional or discriminative stimuli, or by establishing new response-reinforcer relations. This conceptualization may facilitate the empirical analysis of how psychotropic drugs change behavior.  相似文献   
757.
This study examined the contribution of individual and family variables to depressive symptoms among youths in a family-centered culture. Participants were 262 Mexican adolescents (mean age = 15.9 years). At the individual level, gender (being female) and higher levels of perceived stressfulness of life events and ruminative coping style were correlated with higher frequency of depressive symptoms. At the family level, higher levels of perceived parental warmth and acceptance and parental monitoring were correlated with lower levels of depressed mood, whereas higher levels of parent-adolescent conflict were associated with greater frequency of depressive symptoms. Regression analyses confirmed our prediction that both individual factors (gender, ruminative coping) and family factors (parental warmth and parental monitoring) would make unique contributions to depressive symptoms. The model comprised of individual and family variables accounted for 50% of the variance in depressed mood. Moreover, parental warmth and acceptance attenuated the impact of ruminative coping style on adolescents' depressive symptomatology. Findings are discussed in relation to previous research on adolescents in another family-centered culture (China), and directions for future research are proposed.  相似文献   
758.
The brain's histaminergic system has been implicated in hippocampal synaptic plasticity, learning, and memory, as well as brain reward and reinforcement. Our past pharmacological and lesion studies indicated that the brain's histamine system exerts inhibitory effects on the brain's reinforcement respective reward system reciprocal to mesolimbic dopamine systems, thereby modulating learning and memory performance. Given the close functional relationship between brain reinforcement and memory processes, the total disruption of brain histamine synthesis via genetic disruption of its synthesizing enzyme, histidine decarboxylase (HDC), in the mouse might have differential effects on learning dependent on the task-inherent reinforcement contingencies. Here, we investigated the effects of an HDC gene disruption in the mouse in a nonreinforced object exploration task and a negatively reinforced water-maze task as well as on neo- and ventro-striatal dopamine systems known to be involved in brain reward and reinforcement. Histidine decarboxylase knockout (HDC-KO) mice had higher dihydrophenylacetic acid concentrations and a higher dihydrophenylacetic acid/dopamine ratio in the neostriatum. In the ventral striatum, dihydrophenylacetic acid/dopamine and 3-methoxytyramine/dopamine ratios were higher in HDC-KO mice. Furthermore, the HDC-KO mice showed improved water-maze performance during both hidden and cued platform tasks, but deficient object discrimination based on temporal relationships. Our data imply that disruption of brain histamine synthesis can have both memory promoting and suppressive effects via distinct and independent mechanisms and further indicate that these opposed effects are related to the task-inherent reinforcement contingencies.  相似文献   
759.
Receiving instrumental support at work: when help is not welcome   总被引:4,自引:0,他引:4  
Although the role of social support in promoting employees' health and well-being has been studied extensively, the evidence is inconsistent, sometimes even suggesting that social support might have negative effects. The authors examined some psychological processes that might explain such effects. On the basis of the threat-to-self-esteem model, the authors tested the hypothesis that receiving imposed support elicits negative reactions, which are moderated by someone's need for support. The authors distinguished 3 different reactions: (a) self-related, (b) interaction-related, and (c) physiological. The results of an experiment with 48 temporary administrative workers generally confirmed the hypothesis. Imposed support elicited negative reactions, except when there was an unsolvable problem, but even then the effect of imposed support was not positive but neutral.  相似文献   
760.
People have knowledge about relationships (i.e., relational schemas) that is based on their experiences. Because most people have experience with complementary behavior (interaction partners behaving similarly in terms of affiliation but oppositely in terms of control), they expect complementary behavior in their relationships. Like other beliefs about relationships, expectations of complementarity affect self-construal. The authors provide evidence for complementary self-construal; people assimilate to relevant relationship partners on the affiliation dimension and contrast on the control dimension. Consistent with the proposed role of relationship knowledge in these effects, complementary self-construal was moderated by the familiarity of the target, whether people focused on their relationship with or the appearance of the target, and whether the context was relevant for the interpersonal dimension.  相似文献   
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