奖赏预期对面孔情绪加工的影响：一项事件相关电位研究

采用事件相关电位(ERPs)技术考察了奖赏预期对人类面孔情绪识别的影响。实验采用线索-目标范式, 分别记录了被试在奖赏预期条件下以及无奖赏预期条件下对正性、中性和负性面孔进行情绪辨别任务的ERP数据。行为结果显示, 被试在奖赏预期条件下的反应时快于无奖赏预期条件下的反应时, 对情绪面孔的反应时快于对中性面孔的反应时。ERPs数据显示, 奖赏线索比无奖赏线索诱发了更正的P1、P2和P300成分。目标刺激诱发的P1、N170波幅以及N300均受到奖赏预期的调节, 在奖赏预期条件下目标诱发了更正的ERPs。P1、N170、VPP等成分没有受到面孔情绪的影响, 而额中央位置的N300波幅显示情绪(正性与负性)面孔与中性面孔加工的差异。重要的是, N300波幅出现奖赏预期与情绪的交互作用, 正、负情绪加工效应以及负性偏向效应受奖赏预期的差异性影响。正性情绪加工效应不受奖赏预期的影响, 而负性情绪加工效应和负性偏向效应在奖赏预期条件下显著大于无奖赏预期条件下。这些结果说明, 奖赏预期能够调节对面孔情绪的加工, 且不同加工进程中奖赏对情绪加工的调节作用不同。动机性信息调节注意资源的分配, 促进了个体在加工面孔情绪时的负性偏向。

Monetary Incentives Modulate the Processing of Emotional Facial Expressions: An ERP Study

It is widely reported that monetary reward improves performance of cognitive tasks, such as spatial orienting, visual search, and conflict control by increasing task concentration and engagement. The current study used event-related potentials (ERPs) technique to investigate the impact of monetary reward on the discrimination of emotional facial expressions. Participants were asked to discriminate a happy, neutral, or angry face presented at the center of the computer screen, which was preceded by a monetary incentive or a non-incentive cue, and was followed by a feedback stimulus regarding the fastness and correctness of the response. Participants were informed that they would gain additional monetary reward if their reaction times (RTs) on incentive trials meet certain criteria. Behavioral results showed that RTs to emotional faces were generally faster than to neutral faces, and RTs in incentive trials were faster than that in non-incentive trials. Cue-elicited ERPs were modulated by monetary incentive, such that incentive cue elicited larger P1 (130~200 ms), P2 (200~300 ms), and P300 (300~600 ms) amplitude than the non-incentive cue. Target-elicited occipito-temporal P1, N170 and frontal-central N300 amplitudes were modulated by reward anticipation, such that target elicited more positively-going ERPs in incentive condition than that in non-incentive condition. Early P1, N170 and VPP amplitudes were not affected by emotional facial expressions. The neural processes involved in processing emotional faces (happy, angry) and neutral faces diverged 300 ms after stimulus onset. Results showed more positive N300 in emotional conditions than in neutral conditions. Additionally, the amplitude of N300 was influenced by both reward anticipation and emotional valence. While the positive emotion processing effect was not modulated by reward anticipation, the negative emotion processing effect and negative bias effect for the N300 component were larger in incentive condition than in non-incentive condition. These results suggested an impact of reward anticipation on the processing of upcoming emotional facial expressions. Motivational factors may modulate the distribution of attentional resources, which then bias the processing of negative emotion.