【作者】 高笑；

【导师】 陈红；

【作者基本信息】 西南大学 ， 基础心理学， 2010， 博士

【摘要】 负面身体自我(negative physical self, NPS)是个体对身体的消极认知、消极情感体验和相应的行为调控。最近20年,有大量研究关注饮食失调(eating disorders, ED)患者或身体意象失调者对身体信息或食物信息的注意偏向。这些研究报道,对特定信息的注意偏向是饮食失调的影响因素和维持因素之一。然而至今为止,还没有研究系统探查负面身体自我者对身体信息注意偏向机制,包括在不同加工水平、信息的不同效价、注意偏向的时间进程的研究,亦没有研究正式提出负面身体自我者对身体信息注意偏向的理论模型。另外,很少研究涉及负面身体自我者对身体信息注意偏向的脑机制。本研究拟从社会认知取向出发,采用问卷法、实验法,结合眼动追踪技术、事件相关电位(event related potentials, ERP)技术,考查胖负面身体自我图式女大学生对身体信息注意偏向的行为模式及大脑机制,以此建立胖负面身体自我图式者注意偏向的理论模型。本文包括四个研究共9个实验,从横向与纵向两个方面考查胖负面身体自我图式女性对身体信息的注意偏向。研究一和研究二为横向的平行研究,分别从阈下、阈上两个加工水平对不同效价的身体信息注意偏向的时间进程进行考查；研究三在研究一、二的基础上,考查在不同的时程,对不同效价的身体信息注意偏向的资源动用特点；研究四在前三个研究基础上,采用ERP技术,进一步考查对不同效价的身体信息加工大脑活动的时间进程。具体而言,研究一采用视觉点探测掩蔽任务(masked version of the dot probe task),使用胖相关和瘦相关身体词语(实验1)和身体图片(实验2),刺激呈现时间14ms并伴有186ms的后掩蔽,考查胖负面身体自我图式者对身体信息是否存在阈下加工偏向；如果存在,进一步探讨其机制,是注意警觉、解除困难或最初回避。研究二着重考查胖负面身体自我图式女性对不同效价身体信息阈上注意偏向的时间进程机制。这部分研究设计了三个实验方案,实验3、4采用经典的点探测范式,通过改变不同的刺激间隔,考查对身体信息注意偏向的时间进程机制。实验5采用点探测范式与眼动追踪技术相结合的方法,更加精确、直接的探查注意偏向的成分：注意定向、探测速度、注意解除以及注意维持／回避。实验6、7采用经典的线索-靶子范式(cue-targetparadigm),通过改变不同的SOA,考查对身体信息注意解除的时间进程机制。研究三在研究一、二的基础上,着重考查在不同时间进程,胖负面身体自我图式女性对身体信息注意偏向的资源动用特点。图式者对身体信息的注意偏向是一种低效率、高耗能的注意偏向,还是一种高效率、低耗能的注意偏向?对这一问题的探查有助于进一步揭示不同注意偏向成分的认知资源动用特点。实验8采用单任务和双任务的快速序列视觉呈现范式(rapid serial visual presentation),以胖词、瘦词和中性词作为T1,分析在不同时间间隔,负面身体自我图式者对三种T1后T2判断的正确率,以探查不同时程注意偏向的认知资源动用特点。研究四采用快速序列视觉呈现任务,结合ERP技术,考查胖负面身体自我图式女性对身体信息加工的脑机制。研究结果发现,在不同的加工水平,图式者均对身体信息存在加工偏向,而且对胖相关信息和瘦相关信息存在加工分离。在阈下水平,图式者仅对胖相关信息存在加工偏向,且为一种反转的加工模式,即对后续行为反应存在减缓或抑制效应。阈上的注意偏向表现为：对身体信息存在早期的注意警觉；注意脱离或注意解除过程受生理因素(BMI)和心理因素(负面身体自我图式)的共同调节；晚期对胖词存在注意维持,对瘦词存在注意回避。在资源有限的情况下,身体信息能自动进入序列加工；并且在判断身体信息后出现的靶子所产生的注意瞬脱量减小了。这揭示图式者对瘦词和胖词的加工效率更高,需要的时间更短,占用的资源更少。对图式者加工身体信息的脑机制研究发现,胖词在图式者头皮的Fz电极和FCz电极诱发了更大的N1,而对照组没有显著差异。这揭示图式者存在对胖词的早期加工偏向。在顶枕联合区记录到的不同词语诱发的N220波幅亦在实验组被试身上存在差异。瘦词在左侧诱发了更小的N220,而胖词在右侧诱发了更大的N220,不同词语类型在对照组没有发现显著差异。这揭示图式者存在对胖词、瘦词的知觉加工分离。另外,410-480ms时间段在图式者头皮记录到的三种词语类型诱发的P3平均波幅大小关系呈现瘦词>胖词>中性词,而对照组三种词语类型诱发的P3平均波幅大小关系呈现瘦词、胖词>中性词,瘦词和胖词之间没有显著差异。这揭示图式者对胖词、瘦词加工存在晚期的控制加工分离。本文提出了负面身体自我图式者对身体信息的双重加工三阶段模型(dual processing and three stages model)。“双重加工”指两种不同的加工方式,包括自动的、快速的、不需要意志努力的负面身体自我图式联结式加工(associative processes)和精细的、理性的、意识参与的负面身体自我图式规则式加工(rule-based processes)。“三阶段”是在加工时间维度上进行的划分。第一阶段为负性偏向阶段,凡是能够对图式造成威胁的刺激均能够得到优先的心理加工。第二阶段为优势加工阶段,主要是对身体词和非身体词进行区别。第三阶段为精细加工阶段,这一阶段是继优势加工阶段之后对身体信息的进一步加工,能够在特定维度上对身体信息进行区分和评价,如情绪效价维度,内容维度,自我参照等等。更多还原

【Abstract】 Negative physical self (NPS) is defined as the negative cognition, negative emotion and behavior-regulation to his/her own body. During the last 20 years, dozens of studies have focused on attentional bias toward body shape or foods among eating disorders patients and body image distorted individuals. It was reported that attentional bias to body or food related information is one of the risk factors and maintenance factors of eating disorders. So far, few have systematically investigated attentional bias toward body related information among individuals with NPS, and no theoretical model has been well established. Moreover, these researches seldom related to the brain and neural mechanism of the attentional bias. From a social cognitive point of view and by eye tracking and event-related potentials technique, this study aimed to explore the behavior and brain mechanism of attentional bias to body related information in the females with weight-related negative physical self schema, and also establish a theoretical model.Utilizing masked version of the dot probe task, Study 1 investigated subliminal processing of fatness and thinness related information. Study 2 investigated supraliminal processing of fatness and thinness related information. Study 3 explored cognitive resources mechanism of attentional bias toward body related information. Using rapid serial visual presentation and event related potentials, Study 4 investigated brain mechanism of attentional bias toward body related information. The results are as follows:Subliminal processing bias of fatness related information was observed among females with NPS schema, with an inhibition effect on impending behavioral reaction. Supraliminal attentional bias was also obtained with hypervigilance-maintenance pattern of fatness information and hypervigilance-avoidance pattern of thinness related information. Attentional disengagement was modulated by NPS, body mass index (BMI) and also the interaction of NPS and BMI. ERP component are modulated by NPS and body related words. Fatness related words elicited larger N1 amplitudes than thinness related and neutral words did only among females with NPS, which indicated a negative bias toward fatness related words in females with NPS. Thinness related words elicited smaller N220 amplitude at left sites and fatness related words elicited larger N220 amplitude at right sites only among females with NPS, indicating processing dissociation during perception.In light of the present results, we propose a dual processing and three stages model for understanding the behavior and brain mechanism of attentional bias toward body related information among females with NPS schema. Dual processing refers to NPS schema associative processes and NPS schema rule-based processes. Along the time course, three stages were divided, which were not completely independent but is interconnected. The first stage is negative bias stage. Schema related threat information could be processed with higher priority in the first stage. The second stage is advantage processing stage, during which body related information could be distinguished from others. The third stage is precise processing stage. Body related information could be further analyzed and rated on particular dimensions.更多还原