奖赏刺激的脑电反应特征跨文化差异:一个ERP研究

本研究从文化--社会神经科学的角度出发,采用事件相关电位的方法来探究不同文化背景下的个体对具有进化和社会文化代表性的正性刺激—奖赏刺激的脑电反应特征是否具有差异。本研究采用the Door Task实验范式考察了26名中国人和24名高加索白人对不同反馈反应的脑电特征跨文化差异。结果显示,负性反馈条件下诱发的FRN平均波幅比正性反馈条件诱发的平均脑电波幅更负,这种正负反馈的波幅差异只在中国被试中有体现。在P3成分上,在正性反馈条件下,中国被试诱发的脑电波幅大于西方被试,负性反馈条件下,两组无显著差异。研究结果表明,相对于西方被试,中国被试对奖赏反馈刺激可能具有较高的敏感性。这说明中西方文化下的个体对正负性反馈刺激的加工的脑电反应特征存在显著的差异。     

反馈相关负波：一种抑郁症的生物标记物

反馈相关负波(feedback-related negativity, FRN)是一种反映个体奖赏敏感性的脑电成分; 而抑郁症患者的特征之一是奖赏敏感性的减弱。大量横向研究发现了重度抑郁症患者(major depressive disorder, MDD)及有患抑郁症风险群体的FRN异常; 另外, 纵向研究发现FRN的异常能够预测青春期抑郁发作及抑郁症状发展, 压力、睡眠等因素在其中起调节作用。这提示FRN可能在对抑郁症的诊断及分型、抑郁高危群体的筛查及干预等方面具有潜在价值。目前关于FRN的心理功能依然存在一些争议, 在未来的研究中应该进一步明确FRN的功能和测量方法, 并探明抑郁症的异质性和共病对FRN的作用, 也应关注老年人群体中FRN与抑郁症的关系。     

Aggression is associated with greater subsequent alcohol consumption: A shared neural basis in the ventral striatum

Alcohol use and abuse (e.g., binge drinking) are among the most reliable causes of aggressive behavior. Conversely, people with aggressive dispositions (e.g., intermittent explosive disorder) are at greater risk for subsequent substance abuse. Yet it remains unknown why aggression might promote subsequent alcohol use. Both aggressive acts and alcohol use are rewarding and linked to greater activity in neural reward circuitry. Through this shared instantiation of reward, aggression may then increase subsequent alcohol consumption. Supporting this mechanistic hypothesis, participants’ aggressive behavior directed at someone who had recently rejected them, was associated with more subsequent beer consumption on an ad‐lib drinking task. Using functional MRI, both aggressive behavior and beer consumption were associated with greater activity in the bilateral ventral striatum during acts of retaliatory aggression. These results imply that aggression is linked to subsequent alcohol abuse, and that a mechanism underlying this effect is likely to be the activation of the brain's reward circuitry during aggressive acts.

     

Gender and Compensation: Understanding the Impact of Gender and Gender Stereotypes in Children’s Rewards

Children’s understanding of rewards for task completion was examined in the context of gender, and gender-based stereotypes. Eighty-eight children (43 girls, M_overall?=?58.39 months) completed a measure assessing gender-based occupational stereotypes. This measure, along with gender, was used to predict children’s self-reward for undergoing the testing, as well as their reward for a fictional other child having undergone the same procedure. The methodology provided a novel approach for studying reward allocation in children, as it did not require children to divide resources between themselves and another child for completing the same task. An occupation-based stereotype measure was found to predict the self-reward, as well as the reward allocated to the other child. In addition, the participant’s gender predicted self-reward, and an interaction between participant gender and gender of the experimenter contributed to predicting the other child reward. Overall, these findings suggest that gender and gender-based stereotyping have an impact on reward allocation of young children. Implications of these results in the context of reward allocation research among children and adult populations are discussed.     

Exploring the black box of the contingent reward leadership–performance relationship: The role of perceived justice and emotional exhaustion

Using data collected from three different sources (N = 294), we examined a model in which perceived organizational justice (distributive, procedural, and interactional) and emotional exhaustion mediate the relationship between contingent reward leadership (CRL) and two performance indicators, namely organizational citizenship behaviours (OCB) and absenteeism. We found that procedural justice mediates the negative relationship between CRL and emotional exhaustion while controlling for work overload and transformational leadership. We also found that emotional exhaustion plays a mediating role in the relationship between two dimensions of justice (procedural and interactional) and both OCB and absenteeism. Interactional justice and distributive justice were also directly linked to OCB. Implications of these findings for research on leadership, psychological health, and organizational justice are discussed.     

Is an outgroup member in need a friend indeed? Personal and task‐oriented contact as predictors of intergroup prosocial behavior

Intergroup contact, particularly close personal contact, has been shown to improve intergroup relations, mainly by reducing negative attitudes and emotions toward outgroups. We argue that contact can also increase intergroup prosocial behavior. More specifically, we predict that different forms of contact will differentially impact on prosocial behavior directed at individual outgroup members and outgroups as a whole. Data of two studies (N₁ = 264, N₂ = 185), conducted with workgroups in two organizations, show that personal contact is a better predictor of prosocial behavior directed at individual outgroup members, whereas task‐oriented contact is a better predictor of prosocial behavior directed at an outgroup as a whole. Additionally, Study 2 provides evidence that empathy mediates the path from personal contact to individual‐directed prosocial behavior, whereas reward (but not cost) considerations mediate the path from task‐oriented contact to outgroup‐directed prosocial behavior. Implications for research on intergroup contact and prosocial behavior are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Making decisions about now and later: Development of future-oriented self-control

This study explored factors underlying preschoolers’ ability to make future-oriented choices. In a delay-of-gratification choice task, quantity and visibility of the reward was systematically varied. Participants included 90 typically developing children aged 2–4 years. Children made more choices to delay gratification as the quantity of the reward increased from 1 to 4 stickers, but covering the reward did not have an effect. The study extends previous findings on delay of gratification choice tasks in suggesting a developmental pattern beginning with an early appearing “hot” motivational system. Having children think about the present self versus the future self presumably activates a second “cool” representational system. Age differences in the development of this system and its integration with the motivational system may be at the heart of the “U” shaped function observed in the present work, one in which simpler abilities underlying self-control develop in parallel and integrate to produce more complex behaviour. The study thus contributes to our understanding of the development of future-oriented self-control, a milestone central to socialization and the definition of the self.     

Incentive theory: IV. Magnitude of reward

Incentive theory is successfully applied to data from experiments in which the amount of food reward is varied. This is accomplished by assuming that incentive value is a negatively accelerated function of reward duration. The interaction of the magnitude of a reward with its delay is confirmed, and the causes and implications of this interaction are discussed.     

Effects of reward distribution and performance feedback on competitive responding

To implement competitive contingencies, one must select a distribution of unequal rewards and a schedule of feedback for competitors regarding one another's performance. This study investigated three bases for distributing rewards and two performance feedback conditions. Pairs of college students competed over a series of 2-min contests in which the competitive response was a knob pull. A sum of money was divided using a proportional distribution or one of two fixed reward distributions. In the proportional distribution, a subject's proportion of the sum was his or her proportion of the total number of responses. The two fixed distributions were divisions of 100%/0% or 67%/33%. Also, in every contest either subject could make a response that would end the contest prematurely and give both subjects the same amount—a sum equal to 33% of the competitive total. In the two feedback conditions, cumulative responses by each subject were either shown to both subjects during the contest or were not shown. The proportional distribution was clearly superior to either of the fixed distributions in number of responses produced across contests. The proportional distribution with feedback produced the largest number of competitive responses, and the 100%/0% distribution without feedback produced the smallest number. Differences among distributions typically emerged only during later blocks of contests. Fixed distributions of rewards often produced decelerating rates of responding, with losing competitors ending the contests before they were completed. Response-rate decreases were greatest for pairs in which the 2 subjects differed most in their response rates and proportion of wins. The presence of feedback had a small effect, increasing responding for some pairs in the 100%/0% distribution. Performance patterns were interpreted in terms of the consequences arranged for the individual participants by the reward distributions and differences in performance between competitors.     

奖赏性线索启动和调控视觉搜索额顶网络的神经机制

近期关于奖赏性信息与视觉搜索任务的交互作用研究体现在两个层面, 其一是施加外部奖赏能够影响被试的视觉搜索反应时和正确率, 其二是搜索目标本身具有奖赏特性也能够影响行为反应。但是, 奖赏性信息对负责视觉搜索的额顶注意网络的动态启动和调控作用仍不清楚。本研究结合Posner空间预提示范式和视觉搜索范式, 采用快速事件相关功能磁共振成像技术, 分别操纵线索提示阶段的线索奖赏属性(奖赏性vs.非奖赏性)和线索空间注意属性(有效提示目标位置vs.无效提示目标位置), 并操纵目标搜索阶段的目标属性(奖赏性vs.非奖赏性), 探讨以下两个核心问题：(1)在线索提示阶段, 奖赏性线索产生的自上而下注意准备信号的神经基础, 以及该神经基础与传统的空间注意准备信号的异同; (2)在目标搜索阶段, 奖赏性线索对负责视觉搜索的额顶注意网络产生的启动和调控作用, 重点考察对正确的奖赏性信息的定向过程和对错误的奖赏性信息的重新定向过程。