The Neural Basis of Implicit Attitudes Damian Stanley,1 Elizabeth Phelps,1 and Mahzarin Banaji2
Total Page:16
File Type:pdf, Size:1020Kb
CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE The Neural Basis of Implicit Attitudes Damian Stanley,1 Elizabeth Phelps,1 and Mahzarin Banaji2 1New York University and 2Harvard University ABSTRACT—Evidence that human preferences, beliefs, and enable us to rapidly and efficiently react to simple sensory inputs behavior are influenced by sources that are outside the as well as to multifaceted experiences such as individuals, reach of conscious awareness, control, intention, and self- groups, objects, and events we encounter in our social worlds. reflection is incontrovertible. Recent advances in neu- Unlike other organisms, humans have the ability to introspec- roscience have enabled researchers to investigate the tively identify and even change the attitudes they hold. As Max neural basis of these implicit attitudes, particularly atti- Klinger of MnAnSnH said, ‘‘I used to be an atheist, but I gave it up tudes involving social groups. From this research, a model for lent.’’ This ability to examine the contents of our own minds with three identified neural components related to the and manipulate them is uniquely human. Its presence can automatic activation and regulation of implicit attitudes create the illusion that we control more about ourselves and our is beginning to emerge. The amygdala is implicated in the universe than we actually do, and that we know what our pref- automatic evaluation of socially relevant stimuli, while erences are and why we have them. Research in social psy- the anterior cingulate and dorsolateral prefrontal cortices chology has shown that, in addition to our conscious attitudes, are involved in the detection and regulation, respectively, we possess automatically triggered attitudes that can influence of implicit attitudes. Further support for this model comes behavior without our awareness (Fazio, Jackson, Dunton, & from the inclusion of these regions in current models con- Williams, 1995; Greenwald & Banaji, 1995). Because these cerning the cognitive regulation of emotion and the detec- attitudes are ‘‘introspectively unidentified (or inaccurately tion of conflict. The identification of a putative neural identified)’’ (Greenwald & Banaji, 1995, p. 8), they are termed substrate for implicit attitudes has had a direct impact on implicit, thereby distinguishing them from explicit attitudes that psychological research into their nature and operational reflect our conscious thoughts and beliefs. Current models of characteristics. We discuss how this emerging neural model social cognition posit that human social behavior is the com- has influenced current research on implicit attitudes and bined result of these two related but distinct sets of attitudes. describe the importance of such models for directing future research. IMPLICIT ATTITUDES KEYWORDS—implicit attitude; implicit bias; social cogni- tion; social neuroscience; amygdala The distinction between implicit and explicit attitudes emerged only in the last 20 years, primarily motivated by findings from cognitive psychology demonstrating the influence of implicit Attitudes or preferences are a fundamental component of all memory and unconscious cognition on behavior (Greenwald & living systems. They orient the organism toward or away from Banaji, 1995; Bargh & Chartrand, 1999). While theoretically people, things, and events in the world. When plants orient to- driven, in practice the distinction between implicit and explicit ward the sun and flies flee from swatters, their behavior is based often ends up being a methodological one. Studies assessing on a relatively simple and automatic system of preferences (e.g., implicit processes use indirect measures over which the partic- tropisms, taxis) without which survival would be compromised. ipant has little control and of which they may be unaware. Many In humans, the levels of preferences and attitudes that guide such measures require participants to respond as quickly as behavior range from the simple to the highly complex. Attitudes possible, thereby limiting introspection (e.g., Fazio et al., 1995; Nosek, Greenwald, & Banaji, 2006). Others measure physiolog- ical responses, such as skin conductance or indicators of neural Address correspondence to Damian Stanley, Department of Psy- chology, New York University, 6 Washington Place, Rm 865, New activity, to assess participants’ automatic reactions to target York, NY 10003; e-mail: [email protected]. stimuli or concepts (e.g., Phelps et al., 2000). In contrast, studies 164 Copyright r 2008 Association for Psychological Science Volume 17—Number 2 Damian Stanley, Elizabeth Phelps, and Mahzarin Banaji assessing explicit processes usually require conscious delibera- nuclei located bilaterally in the anterior temporal lobe that has tion on the part of the participant and/or rely on self-report. been studied extensively with respect to implicit emotional Indirect measures have been used to assess a wide range of learning and memory, as well as with respect to the automatic implicit attitudes including, but not limited to, those toward effects of emotional stimuli upon cognition and perception (for race, gender, sexual orientation, age, religion, and political review, see Phelps & LeDoux, 2005). Structurally, the amygdala issues (Greenwald, Poehlman, Uhlmann, & Banaji, in press; is well situated to combine social and cognitive input and to Nosek et al., 2007). While informative about specific attitudes, modulate cognition and automatic aspects of behavior. Input to these data have also provided a wealth of information about the the amygdala is diverse, including contributions from low-level characteristics of implicit attitudes in general. Implicit attitudes sensory areas and from brain regions underlying memory and predict behavior such as choices, judgments, and nonverbal higher cognitive processes. Output from the amygdala is also behaviors toward members of other social groups, and in some widespread, ranging from the brain stem and hypothalamus to cases they can be more informative than explicit attitudes are early sensory cortices and cortical association areas. (Fazio et al., 1995; Greenwald et al., in press). In particular, A range of studies have demonstrated that, with its diverse measures of implicit attitudes outperform measures of explicit projections, the amygdala modulates a range of cognitive func- attitudes in socially sensitive domains (e.g., stereotyping and tions, such as memory and attention, as well as autonomic re- prejudice; Green et al., 2007). Implicit attitudes are triggered sponses, in the presence of emotionally salient stimuli (Phelps & automatically, often without awareness, in a manner that can LeDoux, 2005). In particular, the amygdala has been shown to be depend upon the particular social context (Blair, 2002; Fazio et critical for fear learning—that is, the implicit, physiological al., 1995; Greenwald & Banaji, 1995). In addition, they are expression of emotional responses to neutral stimuli that have pervasive, in that they are found across different demographic been paired with an aversive stimulus. Importantly, the amyg- groups and topics (Nosek et al., 2007). Implicit attitudes are dala is also recruited when fear learning is induced indirectly, related to explicit attitudes, but they are distinct in that neither is either through observation or instruction (Phelps & Banaji, robustly predictive of the other (Greenwald et al., in press; Nosek 2005; Phelps & LeDoux, 2005), indicating that it is sensitive et al., 2007). to the types of social cues imperative in the formation of implicit These qualities have led to interest in implicit attitudes and attitudes. The amygdala’s role in evaluative aspects of social their influence on behavior across disciplines as diverse as so- interactions is further supported by lesion and functional cial psychology, neuroscience, law, developmental psychology, imaging work in monkeys (Adolphs, 2003) and humans (Phelps and market research (Greenwald et al., in press; Nosek et al., & LeDoux, 2005). 2007; Phelps & Banaji, 2005). Accompanying this interest is a The amygdala was first linked to implicit attitudes in a study desire to better understand the underlying phenomena that give by Phelps et al. (2000). The authors used fMRI to measure blood- rise to implicit attitudes, as well as to learn how we might reg- oxygen-level dependent (BOLD) responses in White American ulate their impact on our own behavior. Neuroscientific tech- participants while they viewed faces of unfamiliar Black and niques such as functional magnetic resonance imaging (fMRI) White males. In addition, they collected behavioral measures and electroencephalography (EEG) have enabled researchers to assessing the participants’ implicit and explicit race-related begin to elucidate the neural systems involved in the expression attitudes. The magnitude of the amygdala BOLD response when and regulation of implicit attitudes. Importantly, these tech- participants viewed Black (compared to White) faces was sig- niques make it possible not only to investigate the neural sub- nificantly correlated with measures of individuals’ implicit, but strate of implicit attitudes in humans but also to draw not explicit, race-related behavioral attitudes (see Fig. 1a). comparisons across species, allowing animal models to inform These data suggested that the amygdala plays a role in the research on implicit attitudes. The merging of neuroscience and evaluation of other social groups and that this role reflects in- psychology has influenced current theories