“惩前毖后”与“率先垂范”：第三方干预行为的影响效应

第三方干预是维持和发展社会规范的关键力量,对整个人类群体具有进化意义。补偿和惩罚是第三方干预的两种主要形式,二者均是维护社会规范的重要力量,具有恢复得失平衡以及促进规范遵从的积极作用。研究者广泛认可威慑效应是第三方惩罚促进规范遵从的主要作用机制,然而也有许多研究结果与该假说相悖。除威慑作用外,第三方干预行为作为高代价信号,也具有澄清社会规范、改变人们规范知觉的作用,这暗示着信号效应可能也是第三方干预促进规范遵从的重要作用机制。探究第三方惩罚促进规范遵从的边界条件、检验第三方补偿等非破坏性措施在维护社会规范方面的有效性是未来研究的重要方向。     

第三方惩罚对合作行为的影响:基于社会规范激活的解释

第三方惩罚对合作行为的影响有两面性,可能与其激活的社会规范有关。通过有/无第三方的独裁者博弈范式,研究发现合作行为在有第三方时主要受命令性规范影响;在无第三方时,主要受描述性规范影响。第三方惩罚频率越高,个体在有第三方时的合作行为也越高,撤去第三方后个体合作行为的下降也越大。这可能因为第三方惩罚不仅能有效提示群体中的命令性规范(应该如何做),还能暗示出该情境下的描述性规范(大多数人如何做)。     

认知控制在第三方惩罚中的作用

第三方惩罚是一种特殊的利他行为, 在维护社会规范和人类合作中发挥着重要作用。现有研究对遵守社会规范行为及其认知机制进行了大量探讨, 而第三方惩罚这一维护社会规范行为的认知加工过程, 尤其是认知控制在其中发挥的具体作用, 是目前研究的热点之一。通过(1)借助不同技术方法来探究认知控制在第三方惩罚中的具体作用; (2)从发展的视角, 在认知控制发展的关键阶段来考察其作用随年龄的发展变化, 用以解释第三方惩罚这一利他行为的发展轨迹, 完善对第三方惩罚的认知基础的理解, 并构建第三方惩罚决策的心理模型。     

公平与惩罚价格对第三方惩罚需求的影响

为了探讨第三方惩罚的影响因素,分析个体在不同公平情境下面临不同的惩罚成本时会采取怎样的第三方惩罚行为,本研究以171名大学生为被试,采用2×2的混合实验设计,通过设置高低两种不公平情境和3种惩罚价格,对被试的第三方惩罚需求进行实验研究。结果显示,个体的第三方惩罚需求都有随着惩罚价格的升高而降低的趋势;不公平程度显著影响第三方惩罚需求。研究表明,惩罚成本显著影响个体的第三方惩罚的实施;在低不公平情境中,被试面对不同惩罚成本时其第三方惩罚行为之间无显著差异,即各种惩罚成本下出现第三方惩罚行为的可能性均较小;而在高不公平情境中,被试面对不同惩罚成本时的第三方惩罚行为之间差异显著,惩罚成本越低出现第三方惩罚的可能性越大。     

第三方惩罚的演化与认知机制

第三方惩罚一般是指当违反社会规范的行为与自身利益无关时,个体牺牲自我利益来惩罚违规者的行为。最近的研究发现,对于个体而言,第三方惩罚是一种具有适应性的信号,包括建立良好的声誉以及威慑违规者。不同情境下第三方惩罚的功能有所差异,它是一种特殊的利他行为。第三方惩罚依赖于多个系统,涉及情绪反应、共情等社会认知能力以及认知控制等中央执行能力。探讨该行为的演化和认知机制也能贡献于个体、群体和人际层面的社会心理服务工作。     

右侧背外侧前额叶在视觉工作记忆中的因果性作用

以往的影像学研究表明右侧背外侧前额叶皮层(DLPFC)在视觉工作记忆中发挥重要作用, 然而缺乏因果性的证据。本研究旨在考察右侧DLPFC的激活与视觉工作记忆容量的因果关系, 并探讨这一关系受到记忆负荷的调节及其神经机制。被试接受经颅直流电刺激之后完成视觉工作记忆变化检测任务, 根据被试在虚假刺激情况下从负荷4到负荷6任务记忆容量的增量将被试分为低记忆增长潜力组(简称低潜力组)和高记忆增长潜力组(简称高潜力组), 结果发现正性电刺激右侧DLPFC相对于虚假电刺激显著提升了高潜力组被试在低记忆负荷(负荷4)下的记忆容量及其对应的提取阶段的脑电指标SPCN成分。表明右侧DLPFC在视觉工作记忆的提取阶段发挥重要的因果性作用; 正性经颅直流电刺激右侧DLPFC可使工作记忆容量高潜力被试获得更多的脑活动增益, 并导致更好的行为提升效果。     

第三方惩罚与社会规范激活——社会责任感与情绪的作用

社会规范需要被激活才能显著影响个体行为,第三方惩罚（TP）正是这样一个激活的过程。本研究将TP引入独裁者博弈（DG）,社会规范被激活的被试参与了TP与DG,未激活的被试只参与了DG。结果表明,前者在TP之后显著提升了DG中的亲社会行为。进一步的分析发现,在社会规范激活过程中,社会责任感越高的个体被激活的程度越高,对违背社会规范的行为产生的愤怒情绪也越高,从而产生了更高水平的亲社会行为。在排除了实验中其他因素和相关理论的解释后,这一基本的实验结果表明社会规范激活受到社会责任感的影响并伴随着特定情绪的激发。     

第三方惩罚对合作的溢出效应：基于社会规范的解释

第三方惩罚对合作的维系可能来自经济功能或规范提示功能。先前研究没有区分这两种功能, 因而未能回答：当惩罚不足以影响违规收益时, 是否还能促进合作?实验1 (N = 252)发现即使第三方惩罚无法降低违规收益, 依然能抑制自利行为。实验2 (N = 179)发现受过惩罚的违规者在其后的独裁者博弈表现出了更高的合作水平。2(是否旁观惩罚)×2(旁观前后)设计的实验3 (N = 179)显示, 旁观惩罚后被试的合作水平显著高于旁观前, 也高于未旁观惩罚的被试。后两个实验中, 社会规范在惩罚与合作之间均起中介作用。这进一步证实惩罚对合作的促进在很大程度上是通过规范激活来实现的, 并存在两种溢出效应：惩罚抑制了曾经的违规者(纵向溢出效应)和旁观者(横向溢出效应)在新博弈情境下的自私行为。这两种溢出效应的发现补充了文献中占主导地位的经济学解释, 并为理解人类社会长时间、大规模的合作提供了新视角。     

群体偏好与年级对小学生利他惩罚行为的影响

采用独裁者博弈（DG）探讨了群体偏好对不同年级小学生利他惩罚行为的影响。研究1对450名小学生利他惩罚行为的年级发展特点进行了测查。研究2以168名小学生为被试,考察了在独裁者博弈中与独裁者的关系、性别与年级对小学生（第三方）利他惩罚行为的影响。研究3以180名小学生为被试,考察了在独裁者博弈中与接受者的关系、性别与年级对小学生（第三方）利他惩罚行为的影响。结果发现：（1）利他惩罚行为在1至3年级之间有显著增长,3至5年级之间不仅没有增加反而有所下降。（2）3年级小学生开始表现出明显的群体偏好。（3）利他惩罚行为的性别差异不明显,与女生比男生更利他的预期相左。结论：小学生至少在6岁就已经出现了利他惩罚行为且逐渐表现出群体偏好;小学生道德行为发展中可能存在“3年级现象”;女生可能更愿意通过非惩罚的方式达成公平。     

支付与报复：成本形式对第三方惩罚的影响

第三方惩罚不仅对惩罚成本的数量敏感,也对成本形式敏感。在保持成本数量相等的情况下,不同形式的惩罚成本会对第三方惩罚的频率产生不同影响。相较支付形式,当惩罚成本采取报复形式时,被试的第三方惩罚频率显著下降。进一步的实验表明,惩罚频率的变化并非因为不同的成本形式所隐含的风险水平有所差异,而是因为被试对不同的成本形式赋予了不同的主观价值。进一步探索更多形式的惩罚成本是未来研究的重要方向。     

Effects of tDCS over the right DLPFC on attentional disengagement from positive and negative faces: An eye-tracking study

The aim of this study was to increase insight in the neural substrates of attention processes involved in emotion regulation. The effects of right dorsolateral prefrontal cortex (i.e., DLPFC) stimulation on attentional processing of emotional information were evaluated. A novel attention task allowing a straightforward measurement of attentional engagement toward, and attentional disengagement away from emotional faces was used. A sample of healthy participants received 20 minutes of active and sham anodal transcranial direct current stimulation (i.e., tDCS) applied over the right DLPFC on 2 separate days and completed the attention task after receiving real or sham stimulation. Compared to sham stimulation, tDCS over the right DLPFC led to impairments in attentional disengagement from both positive and negative faces. Findings demonstrate a causal role of right DLPFC activity in the generation of attentional impairments that are implicated in emotional disturbances such as depression and anxiety.     

Transcranial direct current stimulation of the right temporoparietal junction impairs third-person perspective taking

Given the current debates about the precise functional role of the right temporoparietal junction (rTPJ) in egocentric and exocentric perspective taking, in the present study we manipulated activity in the rTPJ to investigate the effects on a spatial perspective-taking task. Participants engaged in a mental body transformation task, requiring them to mentally rotate their own body to the position of an avatar, while undergoing anodal, cathodal, or sham transcranial direct current stimulation (tDCS) of the rTPJ. As a control task, participants judged the laterality of a stimulus feature with respect to a fixation cross on the screen. For the first half of the experiment (only during online tDCS), a task-selective effect of tDCS was observed, reflected in slower reaction times following anodal than following cathodal and sham tDCS for the mental body transformation task, but not for the control task. The effects of tDCS were most pronounced for stimuli implying a more difficult mental body transformation. No effects of tDCS were observed during the second half of the experiment. The effects of tDCS were most pronounced for participants scoring low on aberrant perceptual beliefs and spiritual transcendence, suggesting a relation between third-person perspective taking and bodily and perceptual experiences. The finding that anodal stimulation of the rTPJ impairs third-person perspective taking indicates a key role of this region in exocentric spatial processing.     

Noninvasive brain stimulation over M1 and DLPFC cortex enhances the learning of bimanual isometric force control

Motor learning plays an important role in upper-limb function and the recovery of lost functionality. This study aimed to investigate the relative impact of transcranial direct current stimulation (tDCS) on learning in relation to the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) during bimanual isometric force-control tasks performed with both hands under different task constraints. In a single-blind cross-over design, 20 right-handed participants were randomly assigned to either the M1 group (n = 10; mean age, 22.90 ± 1.66 years, mean ± standard deviation) or the DLPFC group (n = 10; mean age, 23.20 ± 1.54 years). Each participant received 30 min of tDCS (anodal or sham, applied randomly in two experiments) while performing the bimanual force control tasks. Anodal tDCS of the M1 improved the accuracy of maintenance and rhythmic alteration of force tasks, while anodal tDCS of the DLPFC improved only the maintenance of the force control tasks compared with sham tDCS. Hence, tDCS over the left M1 and DLPFC has a beneficial effect on the learning of bimanual force control.     

Augmenting Visual Search Performance With Transcranial Direct Current Stimulation (tDCS)

Military personnel endure rigorous and demanding man-hours designated to monitoring and locating targets in tasks such as cyber defense and Unmanned Aerial Vehicle (UAV) operators. These tasks are monotonous and repetitive, which can result in vigilance decrement. The objective of the study was to implement a form of noninvasive brain stimulation known as transcranial DC stimulation (tDCS) over the left frontal eye field (LFEF) region of the scalp to improve cognitive performance. The participants received anodal and cathodal stimulation of 2 mA for 30 min as well as placebo stimulation on 3 separate days while performing the task. The findings suggest that anodal and cathodal stimulation significantly improves detection accuracy. Also, a correlation was detected between percent of eye closure (PERCLOS) and blinking frequency in relation to stimulation condition. Our data suggest that tDCS over the LFEF would be a beneficial countermeasure to mitigate the vigilance decrement and improve visual search performance.     

The effect of bicephalic stimulation of the dorsolateral prefrontal cortex on the attentional bias for threat: A transcranial direct current stimulation study

Previous stimulation studies demonstrated that the dorsolateral prefrontal cortex (DLPFC) is involved in threat processing. According to a model of emotional processing, an unbalance between the two DLPFCs, with a hyperactivation of right frontal areas, is involved in the processing of negative emotions and genesis of anxiety. In the present study, we investigated the role of the right and left DLPFC in threat processing in healthy women who also completed the State-Trait Anxiety Inventory (STAI). We simultaneously modulated the activity of the right and left dorsolateral prefrontal cortex by applying bicephalic transcranial direct current stimulation (tDCS) before participants completed a modified version of the classic Posner task using threatening and nonthreatening stimuli as spatial cues. Anodal stimulation on the right DLPFC with a simultaneous cathodal stimulation over the left side induced a disengagement bias in individuals with low STAI scores and a facilitation bias in individuals with high STAI scores. Anodal stimulation on the left DLPFC with the simultaneous cathodal stimulation over the right side did not affect threat processing. The findings of the present study provided specific support to the hypothesis that unbalanced activation between left and right hemispheres with enhanced activation of the right DLPFC is critical in early top-down threat processing in healthy individuals.     

Transcranial Direct Current Stimulation (tDCS) over the Intraparietal Sulcus Does Not Influence Working Memory Performance

Mixed results of the impact of transcranial direct current stimulation (tDCS) on working memory have been reported. Contrarily to previous studies who focused mainly on stimulating the dorsolateral prefrontal cortex, we modulated the left intraparietal sulcus (IPS) area which is considered to support attentional control aspects of working memory. Using a within-participant experimental design, participants completed three different conditions: anodal stimulation of the IPS, cathodal stimulation of the IPS, and sham stimulation of the IPS. Both visual and verbal working memory tasks were administered. In the visual task, participants had to memorize a random set of colored figures. In the verbal task, participants had to memorize a string of letters. Working memory load was manipulated in both tasks (six figures/letters vs. two figures/letters). No significant differences in accuracy or reaction time between the anodal, cathodal and sham conditions were found. Bayesian analysis supported evidence for an absence of effect. The results of the present study add to the growing body of contradictory evidence regarding the modulatory effects of single session tDCS on working memory performance.     

Cerebellum and processing of negative facial emotions: Cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.     

左右侧颞顶联合区对道德意图信息加工能力的共同作用——基于经颅直流电刺激技术

行为人的意图动机是我们对日常行为的对错做出判断的重要依据。以往研究表明,左右侧颞顶联合区(TPJ)都可能与信念意图的整合加工能力相关,尤其是近年来越来越多的神经刺激研究为TPJ区域与心理状态归因能力之间的因果关系提供了证据。然而,这些研究在实验任务的选取,实验设计的优化,实验结论的稳健性上仍然有改进的空间。基于此,本研究开展了两个在设计上互相补充的实验。实验中被试的TPJ区域会接受一段时间的经颅直流电刺激,并完成一系列的道德判断任务,任务是由意图和结果,以及负性和中性2×2双变量构成的4种条件的故事:无伤人、伤人未遂、意外伤人和伤人成功,被试要对故事主角的行为做出谴责程度的道德判断。结合道德判断的谴责程度和决策时间数据发现,当人们在处理信念意图信息时,左右侧TPJ区域可能是协同互动、共同发挥作用的。在激活右侧TPJ并限制左侧TPJ的情况下,人们对负性结果的谴责程度变高,人们变得更加依赖于行为结果做出道德判断;而在限制右侧TPJ并激活左侧TPJ的情况下,人们对负性意图的谴责程度变高,人们变得更加依赖于行为者的动机做出道德判断。     

Reduction of implicit cognitive bias with cathodal tDCS to the left prefrontal cortex

Implicit associations can interfere with cognitive operations and behavioral decisions without direct intention. Enhancement of neural activity with anodal transcranial direct current stimulation (tDCS) was proposed to reduce implicit associations by means of improved cognitive control. However, a targeted reduction of distractive implicit associations by inhibitory cathodal tDCS, recently shown in spatial–numerical associations, provides an interesting alternative approach to support goal-directed behavior with transcranial brain stimulation. To test this rationale with a sham-controlled cross-over design, a standardized Implicit Association Test (IAT) was performed by 24 healthy participants parallel to 1 mA cathodal or sham tDCS to the left prefrontal cortex. In this double-classification task, insect versus flower pictures and negative versus positive words are mapped together onto two shared response keys with crossed response assignments in separate blocks. Responses were faster when insect + negative and flower + positive stimuli required the same answer (IAT effect). Most critically, the IAT effect was reduced during cathodal tDCS as compared to sham stimulation. Thus, results are consistent with the proposed stimulation rationale, with previous observations, and complementary to previous studies using different tDCS configurations.     

Cerebellum and processing of negative facial emotions: cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.