An Event Related Brain Potential Analysis of Affect and Attitudes

态度和说服过程的自我报告和行为测量依赖于态度刺激引起的二价行为倾向，尽管存在反应扭曲的可能性。当外周躯体内脏测量被用来调查交流和态度时，研究人员传统上试图确定与特定情感状态内在联系的反应。身体内脏反应的多种决定因素，以及内在生理反应和特定情感状态之间的微妙联系，大大限制了先前对态度的生理学评估的有用性。这项研究不依赖于反应倾向或外周生理反应，而是利用事件相关脑电位(ERP)的晚期正向分量与分类过程之间更牢固的关系来研究态度现象。在这种方法中，受试者的态度作为记录事件相关事件时对刺激进行分类的标准。到目前为止的研究中，已经发现ERP中的后期正向电位(LPP)随着受试者对目标刺激的态度和他们对目标刺激之前的刺激的态度之间的差异而变化。因此，嵌入在一个非常积极(消极)刺激的短序列中的态度刺激越消极(积极)，中央顶叶头皮区域的晚期正电位(LPP)幅度就越大(Ccioppo，Crites，Berntson，&amp；Coles，1993；Ccioppo，Crites，Gardner，&amp；Berntson，1994)；即使公开的或口头的反应不能准确反映受试者的态度，这种关系也被发现(Cacioppo等人，1993；Crites，Cacioppo，Gardner，&Amp；这种关系涵盖了性别、一年中的季节、头部大小、简单的恐惧症状态和实验性(语义的、图画的)刺激(Ccioppo等人，1993,1994；Crites等人，1995；Gardner，Ccioppo，Crites，&amp；Berntson，1995)。这些结果表明，这一范式中的LPP波幅反映了态度分类(与反应选择或执行相反)过程。最后，五项不同研究的结果表明，当被试的态度作为对刺激进行分类的标准时，LPP波幅在右半球大于左半球；相反，当被试执行语义分类任务而不是评价性分类任务时，LPP波幅没有被侧化(Ccioppo，Crites，Gardner，&Amp；Berntson，正在审查中；Crites，1994)。本研究的主要目的是使用事件相关电位来检验Ccioppo和Berntson(1994)的评价空间模型中关于情感组织和加工的假设，并将这些预测与情感组织的环丛模型所做的预测进行比较。对态度和劝说过程的自我报告和行为测量依赖于两极测量(例如，“同意”到“不同意”)。这些措施不仅容易受到反应扭曲的影响(例如，撒谎)，而且它们也无法区分对刺激或决定持中立态度的人与那些感到矛盾或冲突的人。例如，对滥用毒品或酒精既不感到积极也不感到消极的人，无法与对毒品或酒精既感到强烈积极又感到强烈消极的人(例如，悔恨的上瘾者)区分开来。然而，开始或继续吸毒或酗酒的原因在这些个人群体之间有很大的不同。在目前的研究中，我们继续致力于开发一种基于大脑的态度测量和潜在的动机基础，该测量方法(1)不要求个人愿意准确地报告他们对人、物体或问题的感觉；(2)不仅区分态度和决定背后的积极和消极动机，而且区分每个动机基础的力量(强度)。在这种方法中，受试者的态度作为对刺激进行分类的标准，同时记录事件相关脑电位(ERPs)。到目前为止的研究中，已经发现ERP中的后期正向电位(LPP)随着受试者对目标刺激的态度和他们对目标刺激之前的刺激的态度之间的差异而变化。因此，在一短串非常积极(消极)的刺激中嵌入的态度刺激越消极(积极)，中央顶叶头皮区域的晚期正电位(LPP)幅度就越大；即使公开的或口头的反应不能准确反映受试者的态度，也可以观察到这种关系。这项研究将在接下来的两年时间里进行，其主要目标是使用事件相关电位来对比情感组织和加工的相互竞争的理论模型，以更好地理解生产性和反生产性决策和行为背后的心理和大脑机制。

Self-report and behavioral measures of attitudes and persuasion processes have relied on the bivalent action disposition aroused by the attitude stimulus despite the potential for response distortion. When peripheral somatovisceral measures have been used to investigate communication and attitudes, investigators have traditionally sought to identify responses that were inherently linked to specific affective states. The multiple determinants of somatovisceral responses and the tenuous links between inherent physiological responses and specific affective states have placed strong limits on the usefulness of prior physiological assessments of attitudes. Rather than relying on response dispositions or peripheral physiological responses, the proposed research exploits a more robust relationship between the late positive component of the event-related brain potential (ERP) and categorization processes to study attitude phenomena. In this approach, a subject's attitude serves as the criterion along which stimuli are categorized while ERPs are recorded. In research to date, a late positive potential (LPP) in the ERP has been found to vary as a function of the discrepancy between subjects' attitude toward a target stimulus and their attitude toward the stimuli that preceded the target stimuls. Thus, the more negative (positive) the attitude stimulus embedded within a short sequence of very positive (negative) stimuli, the larger a late positive potential (LPP) amplitude over the centroparietal scalp region (Cacioppo, Crites, Berntson, & Coles, 1993; Cacioppo, Crites, Gardner, & Berntson, 1994); this relationship was found even when overt or verbal responses did not accurately reflect a subject's attitude (Cacioppo et al., 1993; Crites, Cacioppo, Gardner, & Berntson, 1995), and this relationship generalizes across gender, seasons of the year, head sizes, simple phobia status, and experimental (semantic, pictorial) stimuli (Cacioppo et al., 1993, 1994; Crites et al., 1995; Gardner, Cacioppo, Crites , & Berntson, 1995). These results suggest that the LPP amplitude in this paradigm reflects attitude categorization (in contrast to response selection or execution) processes. Finally, the results of five different studies indicate that the LPP amplitude is larger over the right than left hemisphere when a subject's attitude serves as the criterion along which stimuli are categorized; when subjects perform a semantic rather than an evaluative categorization task, in contrast, the LPP amplitude is not lateralized (Cacioppo, Crites, Gardner, & Berntson, under review; Crites, 1994). The primary goal of the proposed research is to use ERPs to test hypotheses regarding affective organization and processing from Cacioppo and Berntson's (1994) model of evaluative space and to contrast these predictions with those made by the circumplex model of affective organization. Self-report and behavioral measures of attitudes and persuasion processes have relied on bipolar measures (e.g., "agree" to "disagree"). These measures are not only susceptible to response distortions (e.g., lying) but they also fail to differentiate individuals who feel neutrally about a stimulus or decision from those who feel ambivalent or conflicted. For instance, individuals who feel neither positive nor negative about abusing drugs or alcohol cannot be differentiated from those who feel both strongly positive and strongly negative about drugs or alcohol (e.g., a remorseful addict). The reasons for the onset or continuation of drug or alcohol abuse, however, differ dramatically between these groups of individuals. In the current research, we continue work on developing a brain-based measure of attitudes and underlying motivational bases that (1) does not require that individuals be willing to report accurately how they feel about persons, objects, or issues; and (2) differentiates not only between the positive and negative motivations underlying attitudes and decisions but also the force (intensity) of each motivational su bstrate. In this approach, a subject's attitude serves as the criterion along which stimuli are categorized while event related brain potentials (ERPs) are recorded. In research to date, a late positive potential (LPP) in the ERP has been found to vary as a function of the discrepancy between subjects' attitude toward a target stimulus and their attitude toward the stimuli that preceded the target stimuls. Thus, the more negative (positive) the attitude stimulus embedded within a short sequence of very positive (negative) stimuli, the larger a late positive potential (LPP) amplitude over the centroparietal scalp region; this relationship is observed even when overt or verbal responses do not accurately reflect a subject's attitude. The primary goal of the research to be conducted over the next two-year period is to use ERPs to contrast competing theoretical models of affective organization and processing to better understand the psychological and cerebral mechanisms underlying productive and counterproductive decisions and behaviors.