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81.
    
This article presents an interpretation of autoshaping, and positive and negative automaintenance, based on a neural-network model. The model makes no distinction between operant and respondent learning mechanisms, and takes into account knowledge of hippocampal and dopaminergic systems. Four simulations were run, each one using an A-B-A design and four instances of feedfoward architectures. In A, networks received a positive contingency between inputs that simulated a conditioned stimulus (CS) and an input that simulated an unconditioned stimulus (US). Responding was simulated as an output activation that was neither elicited by nor required for the US. B was an omission-training procedure. Response directedness was defined as sensory feedback from responding, simulated as a dependence of other inputs on responding. In Simulation 1, the phenomena were simulated with a fully connected architecture and maximally intense response feedback. The other simulations used a partially connected architecture without competition between CS and response feedback. In Simulation 2, a maximally intense feedback resulted in substantial autoshaping and automaintenance. In Simulation 3, eliminating response feedback interfered substantially with autoshaping and automaintenance. In Simulation 4, intermediate autoshaping and automaintenance resulted from an intermediate response feedback. Implications for the operant-respondent distinction and the behavior-neuroscience relation are discussed.  相似文献   
82.
This article articulates joint priorities for the fields of prevention science and community psychology. These priorities are intended to address issues raised by the frequent observation of natural tensions between community practitioners and scientists. The first priority is to expand the knowledge base on practitioner–scientist partnerships, particularly on factors associated with positive outcomes within communities. To further articulate this priority, the paper first discusses the rapid growth in community-based partnerships and the emergent research on them. Next described is an illustrative research project on a partnership model that links state university extension and public school delivery systems. The article then turns to the second, related priority of future capacity-building for diffusion of effective partnership-based interventions to achieve larger-scale health and well-being across communities. It outlines two salient tasks: clarification of a conceptual framework and the formulation of a comprehensive capacity-building strategy for diffusion. The comprehensive strategy would require careful attention to the expansion of networks of effective partnerships, partnership-based research agendas, and requisite policy-making.  相似文献   
83.
    
Human participants and recurrent (“connectionist”) neural networks were both trained on a categorization system abstractly similar to natural language systems involving irregular (“strong”) classes and a default class. Both the humans and the networks exhibited staged learning and a generalization pattern reminiscent of the Elsewhere Condition (Kiparsky, 1973). Previous connectionist accounts of related phenomena have often been vague about the nature of the networks’ encoding systems. We analyzed our network using dynamical systems theory, revealing topological and geometric properties that can be directly compared with the mechanisms of non‐connectionist, rule‐based accounts. The results reveal that the networks “contain” structures related to mechanisms posited by rule‐based models, partly vindicating the insights of these models. On the other hand, they support the one mechanism (OM), as opposed to the more than one mechanism (MOM), view of symbolic abstraction by showing how the appearance of MOM behavior can arise emergently from one underlying set of principles. The key new contribution of this study is to show that dynamical systems theory can allow us to explicitly characterize the relationship between the two perspectives in implemented models.  相似文献   
84.
    
The magnitude and predictors of longitudinal behavioral change are reported in a cohort of homosexual men at risk for AIDS. Self-reports of sexual behavior were obtained at two points in time separated by an interval of approximately six months. These self-reports were used to construct both dichotomous and continuous measures of changes in behavior consistent with reduction in the transmission of the AIDS virus (HIV). Although there was considerable variability in behavior. mean changes were consistently in the desired direction. Avoidance of anonymous sexual partners, monogamy, and modification of receptive anal sex to reduce exposure to semen by condom use or withdrawal prior to ejaculation appeared to be especially important in this cohort. Both multiple linear regression and multiple logistic regression were used to examine the relationship between a model of health behavior and these outcomes. Variables examined included knowledge of AIDS. perceived risk of AIDS. the perceived efficacy of behavior in reducing AIDS risk, difficulties with sexual impulse control, belief in biomedical technology to provide a prevention or cure, social norms supportive of behavioral change, and gay network affiliation. Of all these factors, only the availability of supportive peer norms was consistently, significantly and positively related to multiple measures of outcome. Differences between these analyses and longitudinal analyses reported elsewhere are discussed. These results suggest the policies regarding HIV antibody testing should be developed cautiously. taking account of the failure of a sense of risk to predict subsequent behavioral change. They also emphasize the important role of gay organizations in developing social norms supportive of behavioral risk reduction.  相似文献   
85.
    
Despite the influence of social support on physical and mental health, few studies have examined why some close ties are more supportive than others. Though religion provides a rich context for social interaction and a meaningful social identity, it has received little attention in the social support literature. A growing literature on religion and health offers insight into how religion affects social support processes. Using dyadic network data derived from the nationally representative 2006 Portraits of American Life Study, I examine how the religious dimensions of close, nonhousehold ties relate to provision of social support. Results from logistic regression analyses indicate that (controlling for a range of other social tie characteristics) same‐faith ties are significantly more likely to be sources of help “in times of need,” while religious discussion is a strong predictor of receiving both help and advice. The effect of religious homophily is strongest for evangelical Protestants and African‐American Protestants. My findings underscore the need for social support researchers to consider the role of religion in shaping support processes in close relationships.  相似文献   
86.
The Wernicke-Lichtheim-Geschwind (WLG) theory of the neurobiological basis of language is of great historical importance, and it continues to exert a substantial influence on most contemporary theories of language in spite of its widely recognized limitations. Here, we suggest that neurobiologically grounded computational models based on the WLG theory can provide a deeper understanding of which of its features are plausible and where the theory fails. As a first step in this direction, we created a model of the interconnected left and right neocortical areas that are most relevant to the WLG theory, and used it to study visual-confrontation naming, auditory repetition, and auditory comprehension performance. No specific functionality is assigned a priori to model cortical regions, other than that implicitly present due to their locations in the cortical network and a higher learning rate in left hemisphere regions. Following learning, the model successfully simulates confrontation naming and word repetition, and acquires a unique internal representation in parietal regions for each named object. Simulated lesions to the language-dominant cortical regions produce patterns of single word processing impairment reminiscent of those postulated historically in the classic aphasia syndromes. These results indicate that WLG theory, instantiated as a simple interconnected network of model neocortical regions familiar to any neuropsychologist/neurologist, captures several fundamental "low-level" aspects of neurobiological word processing and their impairment in aphasia.  相似文献   
87.
The three lineages of information,—the genetic, the cultural and artifactual—will increasingly merge their constituent information contents through advances in biotechnology and information technology. This will redefine what constitutes “social” and what constitutes “community.” A community's members communicate with their “significant others” and change their internal information states (and their internal and external behaviors). Under conditions of merging, information exchanges occur across all the three lineages. In this sense, the concept of significant other,—that is, a communicating entity—, is now spread from human communities to encompass also the biological and the artifactual. A seamless merging between the three realms now occurs affecting their respective internal information stores. The resulting image of interactions that now arises is of multiple oceans of communities, operating at different levels, the genetic, the cultural and the artifactual. There are exchanges across the different levels, up and down and sideways, as information is translated from one realm to the other. These dynamics result in changes in the evolutionary characteristics of each lineage and sub‐lineage, including the internal perceptions from within a lineage, namely in the language of evolutionary epistemology, its “meanings” and “hypotheses” on the world. A future sociology must necessarily take into account these factors and incorporate the dynamics of all three realms.  相似文献   
88.
Transactive memory theory suggests that general awareness of expertise location in a group is sufficient to predict expertise seeking. Yet expertise seeking is, at least in part, a social phenomenon between two individuals embedded in a network of social relationships. Taking a multilevel, network perspective, we examined the interplay of affective relationships and awareness on expertise seeking in groups. Hypotheses were tested using network data collected from 693 employees in 53 sales groups. HLM analysis results indicated that awareness of expertise distribution positively influenced the decision to seek expertise at all levels of analysis examined. In addition, both positive and negative affective relationships influenced expertise seeking, although their pattern of influence differed across different levels of analysis. More specifically, having either a positive or a negative affective relationship with another group member affected the decision to seek expertise from that person. Although having many positive relationships had a positive effect on expertise seeking, having many negative affective relationships had no effect. Moreover, having both an awareness and a positive affective relationship with another group member amplified their positive effect on expertise seeking. Last, individuals who had more negative affective ties were less likely to leverage the positive impact of each awareness relationship on expertise seeking.  相似文献   
89.
In spite of their unusual orthographic and phonological form, acronyms (e.g., BBC, HIV, NATO) can become familiar to the reader, and their meaning can be accessed well enough that they are understood. The factors in semantic access for acronym stimuli were assessed using a word association task. Two analyses examined the time taken to generate a word association response to acronym cues. Responses were recorded more quickly to cues that elicited a large proportion of semantic responses, and those that were high in associative strength. Participants were shown to be faster to respond to cues which were imageable or early acquired. Frequency was not a significant predictor of word association responses. Implications for theories of lexical organisation are discussed.  相似文献   
90.
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