生活中，人们总是倾向于认为自己会事事顺心，而一些糟糕的事情不会发生在自己的身上。美国科学家近日的研究对此提供了支持，他们发现大脑中的两个区域能帮助人们对事物抱乐观态度。相关论文10月24日在线发表于《自然》上。
此次研究由美国纽约大学的认知神经学家Elizabeth Phelps领导完成。她和同事让15个志愿者去想象不同的生活事件，包括得意事件（如获奖）和不得意事件（如和情侣分手），并让其中一半的志愿者想象这些事件在未来发生，另一半则想象在过去发生。研究人员随后用功能核磁共振成像（fMRI）技术扫描了这些志愿者的脑部活动。
在扫描之后的调查问卷中，志愿者表示，相比较糟糕的未来景象，他们能更生动快速地想象出美好的未来事件。在乐观心理测试中得高分的人身上，这种差别尤其明显。
fMRI扫描结果给出了相关解释。扫描发现，大脑中的两个区域——杏仁核（amygdala）和前喙扣带皮质（rACC），其活性在志愿者想象未来积极事件时比在想象未来消极事件时要强得多。比较起来，最乐观的志愿者在想象消极未来事件时的rACC活性最低。
哈佛大学心理学家Daniel Schacter表示，杏仁核和rACC在调节情绪方面都具有重要作用，当人们想象消极未来事件时，它们活性的降低有助于减弱潜在的痛苦思想，使人不会沉浸到消极情绪中去。（科学网 梅进/编译）
原始出处:
Nature advance online publication 24 October 2007 | doi:10.1038/nature06280; Received 7 July 2007; Accepted 19 September 2007; Published online 24 October 2007
Neural mechanisms mediating optimism bias
Tali Sharot1,2, Alison M. Riccardi1, Candace M. Raio1 & Elizabeth A. Phelps1
Department of Psychology, New York University, New York 10003, USA
Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
Correspondence to: Elizabeth A. Phelps1 Correspondence and requests for materials should be addressed to E.A.P. (Email: liz.phelps@nyu.edu).
Humans expect positive events in the future even when there is no evidence to support such expectations. For example, people expect to live longer and be healthier than average1, they underestimate their likelihood of getting a divorce1, and overestimate their prospects for success on the job market2. We examined how the brain generates this pervasive optimism bias. Here we report that this tendency was related specifically to enhanced activation in the amygdala and in the rostral anterior cingulate cortex when imagining positive future events relative to negative ones, suggesting a key role for areas involved in monitoring emotional salience in mediating the optimism bias. These are the same regions that show irregularities in depression3, which has been related to pessimism4. Across individuals, activity in the rostral anterior cingulate cortex was correlated with trait optimism. The current study highlights how the brain may generate the tendency to engage in the projection of positive future events, suggesting that the effective integration and regulation of emotional and autobiographical information supports the projection of positive future events in healthy individuals, and is related to optimism.
