This study examines the relationship between three types of Internet use (information, entertainment, and interactive contacts) and two types of political efficacy (external and internal) among U.S. college students. Information related Internet use and interactive contacts predict college students' internal political efficacy. An unexpected finding was that visiting public agency sites negatively influenced college students' external political efficacy. This implies that the quality of current public sites is below the expectation of college students and that respondents who visited those sites might develop political cynicism. This study also reveals that online news sites are becoming a primary news source for college students. 相似文献
The dentate gyrus (DG) is among the few areas in the mammalian brain where production of new neurons continues in the adulthood. Although its functional significance is not completely understood, several lines of evidence suggest the role of DG neurogenesis in learning and memory. Considering that long-term potentiation (LTP) is a prime candidate for the process underlying hippocampal learning and memory, these results raise the possibility that LTP and neurogenesis are closely related. Here, we investigated whether or not LTP induction in the afferent pathway triggers enhanced proliferation of progenitor cells in the DG. LTP was induced by tetanic stimulation in perforant path-DG synapses in one hemisphere, and the number of newly generated progenitor (BrdU-labeled) cells in the DG was quantified. Compared with the control hemisphere (stimulated with low-frequency pulses), the LTP-induced hemisphere contained a significantly higher number of newly generated progenitor cells in the dorsal as well as ventral DG. When CPP, an NMDA receptor antagonist, was administered, tetanic stimulation neither induced LTP nor enhanced progenitor cell proliferation, indicating that NMDA receptor activation, rather than tetanic stimulation per se, is responsible for enhanced progenitor proliferation in the control animal. Our results show that tetanic stimulation of perforant path sufficient to induce LTP increases progenitor proliferation in adult DG in an NMDA receptor-dependent manner. 相似文献
Dennis and Ahn (2001) found that during contingency learning, initial evidence influences causal judgments more than does later evidence (a primacy effect), whereas López, Shanks, Almaraz, and Fernández (1998) found the opposite (a recency effect). We propose that in contingency learning, people use initial evidence to develop an anchoring hypothesis that tends to be underadjusted by later evidence, resulting in a primacy effect. Thus, factors interfering with initial hypothesis development, such as simultaneously learning too many contingencies, as in López et al., would reduce the primacy effect. Experiment 1 showed a primacy effect with learning contingencies involving only one outcome but no primacy effect with two outcomes. Experiment 2 demonstrated that the magnitude of the primacy effect correlated with participants' verbal working memory capacity. It is concluded that a critical moderator for exhibition of the primacy effect is task complexity, presumably because it interferes with initial hypothesis development. 相似文献
The theory-based model of categorization posits that concepts are represented as theories, not feature lists. Thus, it is interesting that the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) established atheoretical guidelines for mental disorder diagnosis. Five experiments investigated how clinicians handled an atheoretical nosology. Clinicians' causal theories of disorders and their responses on diagnostic and memory tasks were measured. Participants were more likely to diagnose a hypothetical patient with a disorder if that patient had causally central rather than causally peripheral symptoms according to their theory of the disorder. Their memory for causally central symptoms was also biased. Clinicians are cognitively driven to use theories despite decades of practice with the atheoretical DSM. 相似文献
Abstract— Spoken word recognition is characterized by multiple activation of sound patterns that are consistent with the acoustic-phonetic input. Recently, an extreme form of multiple activation was observed: Bilingual listeners activated words from both languages that were consistent with the input. We explored the degree to which bilingual multiple activation may be constrained by fine-grained acoustic-phonetic information. Ina head-mounted eyetracking experiment, we presented Spanish-English bilinguals with spoken Spanish words having word-initial stop consonants with either English- or Spanish-appropriate voice onset times. Participants fixated interlingual distractors(nontarget pictures whose English names shared a phonological similarity with the Spanish targets) more frequently than control distractors when the target words contained English-appropriate voice onset times. These results demonstrate that fine-grained acoustic-phonetic information and a precise match between input and representation are criticalfor parallel activation of two languages. 相似文献
Objective: This study was to evaluate the effects of psychosocial interventions on survival in adult patients with cancer.
Method: MEDLINE via PubMed, Cochrane Library CENTRAL, CINAHL, and Korean electronic databases (September 2014) were searched. Methodological quality was assessed using Cochrane’s Risk of Bias for randomized studies. The RevMan 5.3 program of the Cochrane library was used for data analysis.
Results: Fifteen randomized controlled trials met the inclusion criteria, with a total of 2940 participants. Overall, psychosocial interventions was not associated with better survival (HR = .83, 95% CI [.68, 1.10], p = .06, I2 = 64%). In subgroup analysis, based on six trials with 1448 subjects, psychoeducational interventions for cancer patients with non-metastatic at intervention implementation resulted in a 41% reduction in the risk of dying of cancer (HR = .59, 95% CI [.49, .71], p < .001, I2 = 0%). For psychoeducational intervention, significant survival benefit were found when health staff delivered the intervention and at a follow-up time of more than 10 years.
Conclusions: Use of psychoeducational interventions for cancer patients at early stage appeared to have beneficial effects on survival, preferably for delivering of health staff. However, conduct of further psychosocial studies with adequate power will lead to better understanding of the effects of treatments on survival outcome. 相似文献
The criterion problem was one of the focal points of early studies of creativity, but several useful criteria have been developed in the last few decades. The investigation reported here represents additional progress. This report (a) describes a new quality of creative achievement index for each domain of the Creative Activity and Accomplishment Checklist (CAAC); (b) compares quality and quantity of creative activity and accomplishment using CAAC data from 202 students; and (c) introduces 2 new scales for the CAAC, one representing everyday creativity and the other technological creativity. The advantages of the modified CAAC include the assessment of both quality (i.e., socially recognized) and quantity of creative achievement, as well as additional breadth in the domains that can be reliably assessed. Analyses of CAAC data confirmed that (a) all domains, including everyday and technological creativity, were reliable in the sample of students and (b) the quality of creative activity did indeed differ from its quantity. There were few sex differences, but boys outperformed girls in technological creativity and girls outperformed boys in the arts. Limitations and future research are noted. 相似文献