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于调查沟通和态度时，研究人员传统上寻求识别与特定情感状态固有联系的反应。躯体内脏反应的多重决定因素以及固有生理反应与特定情感状态之间的微弱联系，极大地限制了先前对态度的生理评估的有效性。本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）的后期积极成分与分类过程之间更强大的关系来研究态度现象。在这种方法中，受试者的态度作为刺激分类的标准，同时记录erp。迄今为止的研究发现，ERP中的迟发正电位（late positive potential， LPP）随被试对目标刺激的态度与对目标刺激之前的态度之间的差异而变化。因此，在短序列的非常积极（消极）刺激中嵌入的消极（积极）态度刺激越多，头皮中央顶叶区域的晚期积极电位（LPP）振幅就越大（Cacioppo, Crites, Berntson, & & Coles, 1993; Cacioppo, Crites, Gardner, & & Berntson, 1994）；即使公开或口头反应不能准确反映被试的态度，也能发现这种关系（Cacioppo et al., 1993; Crites, Cacioppo, Gardner, & Berntson, 1995），而且这种关系在性别、季节、头部大小、单纯恐惧状态和实验（语义、图像）刺激（Cacioppo et al., 1993, 1994; Crites et al., 1995; Gardner, Cacioppo, Crites, & Berntson, 1995）中都有推广。这些结果表明，这种范式中的LPP振幅反映了态度分类（相对于反应选择或执行）过程。最后，五项不同的研究结果表明，当被试的态度作为刺激分类的标准时，LPP在右半球的振幅大于左半球；相反，当被试执行语义分类任务而不是评价分类任务时，LPP振幅不会横向化（Cacioppo, Crites, Gardner, &; Berntson, under review; Crites, 1994）。本研究的主要目的是利用erp来检验Cacioppo和Berntson（1994）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形模型进行对比。态度和说服过程的自我报告和行为测量依赖于双相测量（例如，“同意”到“不同意”）。这些测量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感到中立的人与感到矛盾或矛盾的人。例如，无法将对滥用药物或酒精既不感到积极也不感到消极的人与对药物或酒精既感到积极又感到强烈消极的人（例如，懊悔的瘾君子）区分开来。然而，药物或酒精滥用开始或持续的原因在这些群体之间差别很大。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和潜在动机基础的测量方法，它(1)不要求个人愿意准确地报告他们对人、物或问题的感受；(2)不仅区分了态度和决策背后的积极动机和消极动机，还区分了每种动机的力量（强度）。在这种方法中，受试者的态度作为刺激分类的标准，同时记录事件相关脑电位（ERPs）。迄今为止的研究发现，ERP中的迟发正电位（late positive potential， LPP）随被试对目标刺激的态度与对目标刺激之前的态度之间的差异而变化。因此，在短序列的非常积极（消极）刺激中嵌入的消极（积极）态度刺激越多，中脑顶叶区域的晚期正电位（LPP）振幅越大；这种关系即使在公开或口头反应不能准确反映被试态度的情况下也能观察到。该研究将在未来两年进行，其主要目标是利用erp来对比情感组织和处理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.