Are good students desirable friends? Evidence for friendship selection among elementary students / ¿Son los buenos estudiantes amigos deseables? Evidencia para la selección de amistad entre estudiantes de educación primaria

Abstract

This study assesses the relationship between friendship networks and academic performance among third graders from one school in Santiago, Chile. Longitudinal social network analysis (RSiena) was used to test whether friendship selection is driven by academic performance and if befriended peers tend to influence each other on their academic performance, including gender as a covariate. Results show a positive relationship between academic performance and number of friendship nominations received, and a higher probability of same-gender friendships. Students with higher academic achievement are more likely to be nominated as friends, especially by peers with lower academic achievement. These results suggest that elementary students value high performance as a desirable characteristic in their friends.     

The structure of “communities” and communications in the new millennium

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.     

Psychoacoustic cues to emotion in speech prosody and music

There is strong evidence of shared acoustic profiles common to the expression of emotions in music and speech, yet relatively limited understanding of the specific psychoacoustic features involved. This study combined a controlled experiment and computational modelling to investigate the perceptual codes associated with the expression of emotion in the acoustic domain. The empirical stage of the study provided continuous human ratings of emotions perceived in excerpts of film music and natural speech samples. The computational stage created a computer model that retrieves the relevant information from the acoustic stimuli and makes predictions about the emotional expressiveness of speech and music close to the responses of human subjects. We show that a significant part of the listeners’ second-by-second reported emotions to music and speech prosody can be predicted from a set of seven psychoacoustic features: loudness, tempo/speech rate, melody/prosody contour, spectral centroid, spectral flux, sharpness, and roughness. The implications of these results are discussed in the context of cross-modal similarities in the communication of emotion in the acoustic domain.     

Impact of negative affectively charged stimuli and response style on cognitive-control-related neural activation: An ERP study

The canonical AX-CPT task measures two forms of cognitive control: sustained goal-oriented control (“proactive” control) and transient changes in cognitive control following unexpected events (“reactive” control). We modified this task by adding negative and neutral International Affective Picture System (IAPS) pictures to assess the effects of negative emotion on these two forms of cognitive control. Proactive and reactive control styles were assessed based on measures of behavior and electrophysiology, including the N2 event-related potential component and source space activation (Low Resolution Tomography [LORETA]). We found slower reaction-times and greater DLPFC activation for negative relative to neutral stimuli. Additionally, we found that a proactive style of responding was related to less prefrontal activation (interpreted to reflect increased efficiency of processing) during actively maintained previously cued information and that a reactive style of responding was related to less prefrontal activation (interpreted to reflect increased efficiency of processing) during just-in-time environmentally triggered information. This pattern of results was evident in relatively neutral contexts, but in the face of negative emotion, these associations were not found, suggesting potential response style-by-emotion interaction effects on prefrontal neural activation.     

Cognitive consequences of individual differences in arousal asymmetry

Prior research has demonstrated that semantic organization in the right hemisphere (RH) is more diffuse and specialized for distant semantic associates than is semantic organization in the left hemisphere (LH). The present research explored individual differences in this regard. If the RH is more specialized for distant semantic associates, then individuals with a more active RH should display greater activation of distant semantic associations. Two experiments were conducted to examine this issue. In both studies a line bisection task was used to assess arousal asymmetry. In Experiment 1, greater RH activation was associated with the ability to generate remote associates to three word stimuli. In Experiment 2, relatively greater RH activation was associated with enhanced priming of distant semantic associates. Taken together, these experiments demonstrate that arousal asymmetry is an individual difference variable that is related to variability in semantic organization and retrieval.     

Birth of an Abstraction: A Dynamical Systems Account of the Discovery of an Elsewhere Principle in a Category Learning Task

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.     

Magnitude and determinants of behavioral risk reduction: Longitudinal analysis of a cohort at risk for AIDS

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.     

视觉词汇加工的动态神经网络及其形成

揭示大脑加工的神经网络机制成为认知神经科学研究的最新取向.本研究以视觉词汇加工脑区(VWFA)的神经功能作为切入点,探讨视觉词汇加工神经网络的动态机制及其形成.研究一考察VWFA在刺激驱动和任务调节下的动态激活,及其与语音、语义脑区所组成神经网络的动态机制.研究二通过跨文化对比以及儿童阅读发展研究,阐明语言经验对视觉词汇加工网络的塑造作用.研究三对比功能网络、静息网络以及白质纤维束联结,探讨视觉词汇加工网络的动态联结及其形成.研究结果有助于建构视觉词汇加工的神经生理模型,为基于脑科学的阅读教学和阅读障碍矫治奠定理论基础,为认知神经科学研究提供了新的思路.     

伤害回避的脑机制及其生物基础

伤害回避是指个体对厌恶刺激信号做出强烈的反应,并学会被动地回避惩罚的一种倾向,这一倾向使得个体反复思考未来的结局,并谨慎小心地对待不确定情景中的事件,进而更有可能诱发情感障碍。伤害回避涉及的神经网络包括三个子网络,即额顶叶-前扣带皮层的连接、皮层-杏仁核的连接和白质通道的结构性连接,这三个子网络分别与羞怯感-易疲劳性、预期担心以及不确定环境中的害怕情绪有关。而其生物基础则包括单一基因多态性和基因多态间的交互作用。今后的研究应该集中在深化伤害回避神经网络与生物基础间的联合机制、研究三种及以上基因多态间的交互作用、考察其他因素对基因效应的调节作用、注重伤害回避四种亚型相关神经网络之间的连接、探讨5-HT4等其他几种5-羟色胺受体多态性与伤害回避的关系以及分析伤害回避内部机制在抗抑郁治疗中的作用等方面。     

The impact of interpersonal affective relationships and awareness on expertise seeking: A multilevel network investigation

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.