Toward a Biological Understanding of Mortality Salience (And Other Threat Compensation process

Social Cognition, Vol. 30, No. 6, 2012, pp. 715–733 715 © 2012 Guilford Publications, Inc. Correspondence concerning this article should be addressed to Michael Inzlicht, Ph.D., Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada; E-mail: Michael.Inzlicht@utoronto.ca. TRITT ET AL. WHAT’S SO SPECIAL ABOUT DEATH? ToWarD a biologiCal UnDersTanDing of morTaliTy salienCe (anD oTher ThreaT CompensaTion proCesses) Shona M. Tritt and Michael Inzlicht University of Toronto eddie harmon-Jones University of New South Wales Terror management theorists have proposed explanations of why death anxiety has a special status beyond other anxieties and furthermore argue that awareness of death elicits a defense mechanism that is qualitatively different from other sorts of threat-defense mechanisms. Our review sug- gests that the biological mechanisms through which thoughts of mortality motivate defensive behavior are not unique. rather, we propose that an evolutionarily primitive, biologically based anxiety system underlies mor- tality salience (MS) effects. Death anxiety may well be a mainspring of hu- man activity, yet we suggest that a fundamental set of biological responses to uncertainty—and the processes associated with them—lie at the root of MS defenses. Our proposed motivational account of mortality salience provides a biologically informed, mechanistic elucidation of threat-com- pensation processes that may be applied to a wide range of social psycho- logical phenomena. Based upon cultural anthropologist Ernest Becker’s (1973) theory of Generative Death Anxiety, terror management theory (TMT; Greenberg, Pyszczynski, & Solo- mon, 1986) proposes that much of human behavior is unconsciously generated to deflect fear of inevitable death. TMT has been applied to a wide variety of do- mains and has a large following. Since its original conception in 1986, a new field of social psychology, experimental existential social psychology, has been established. Indeed, over 5,300 articles have been published citing the term terror management since the mid-80s and a widely disseminated, award-winning film, Flight from Death (Shen, 2006), has been produced. ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 高亮 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 高亮 ymjymj 高亮 ymjymj 铅笔 ymjymj 铅笔 716 TriTT eT al. TMT has not been without its detractors, however. Some have argued that the putative mortality salience defense effect is driven by fundamental psychologi- cal needs not specific to death management, such as general needs for certainty, meaning, and control. TMT theorists have accorded special status to death anxiety, arguing that it is distinct from—and supersedes—all other anxieties (Greenberg & Arndt, 2011; Greenberg et al., 1986). Yet such theorists have not proposed any biological mechanism to account for what they suggest is its pervasive influence upon human behavior. We review the research literature related to the biological basis of threat-defense responses in an effort to account for mortality salience effects. In doing so, we ad- dress the issue of whether awareness of death elicits a defense mechanism that is qualitatively different from other sorts of threat-defense process mechanisms. Based on this review, we suggest that the biological mechanisms through which thoughts of mortality motivate defensive behavior are not unique. Rather, a gen- eralized, evolutionarily primitive, anxiety system may underlie mortality salience effects. This broad-based motivational account of defense against death anxiety provides a biologically informed, mechanistic elucidation of threat-compensation processes that may be applied to a wide range of social psychological phenomena. morTaliTy salienCe Defense: a seleCTive revieW of The proposeD meChaniCs Proponents of TMT suggest that humans, unlike other animals, have the cognitive capabilities to conceive of their own mortality, which in turn instills in them an anxiety like no other (Greenberg & Arndt, 2011; Greenberg et al., 1986). As a result, they suggest that humans have developed a unique system of buffering this death anxiety. TMT posits a dual-process model in which (1) conscious thoughts of death are avoided by proximal defenses such as rational threat-focused attempts to sup- press awareness or distract attention from death, and (2) unconscious thoughts of death are defended against with distal defenses such as bolstering conceptions of self and reality that provide a sense of symbolic immortality (Pyszczynski, Green- berg, & Solomon, 1999). Distal defenses have been of particular interest to social psychologists. TMT theorists have proposed two fundamental defenses that alleviate existential terror: (1) a cultural worldview—a shared symbolic construction of reality that entails a set of standards for attaining a sense of personal value, and (2) self-esteem, which is facilitated by the belief that one is living up to the standards of value proscribed by a cultural worldview (Pyszczynski et al., 1999). TMT advocates argue that research supports the existence of both of these pro- cesses. Reminding individuals of their mortality, a paradigm known as mortality salience (MS), leads them to exhibit an increased need to believe in their cultural worldview. Yet this effect is attenuated among individuals with stable, high self- esteem (Harmon-Jones, Simon, Greenberg, Pyszczynski, Solomon, & McGregor, 1997; Schmeichel, Gaillot, Filardo, McGregor, Gitter, & Baumeister, 2009). The MS paradigm has been exemplified in a great number of studies in which experimenters remind participants of their mortality, administer a distractor task to ensure that the participants are not able to work through their death anxiety with rational proximal defenses, and then take note of increased need for faith in ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 ymjymj 线条 WhaT’s so speCial aboUT DeaTh? 717 their cultural worldview (see Burke, Martens, & Faucher, 2010 for meta-analytic review). The increased need for faith in the worldview is often associated with measures of cultural worldview defense, which is operationalized in terms of either more positive or more negative evaluation of people and ideas that respectively support or disconfirm their worldview. For example, MS has been found to lead to more favorable evaluations of indi- viduals who uphold culturally accepted moral standards (e.g., Florian & Mikulinc- er, 1997), but to less favorable evaluations of individuals who have transgressed against culturally accepted morals (e.g., Florian & Mikulincer, 1997). Following MS, participants have also been shown to judge less positively others who have criticized their culture (e.g., Greenberg, Simon, Pyszczynski, Solomon, & Chatel, 1992), or are dissimilar in some way from themselves (e.g., McGregor et al., 1998). MS moreover leads to more discomfort when perceiving behavior that is coun- ter to cultural norms (Greenberg, Simon, Porteus, Pyszczynski, & Solomon, 1995). Consistent with the second type of distal MS defense strategy proposed by TMT, individuals with high, stable self-esteem show less anxiety in response to general anxiety threats (Greenberg, Solomon, et al., 1992) and less worldview defense in response to MS (Harmon-Jones et al., 1997; Schmeichel et al., 2009).1 TMT theorists suggest that it is the accessibility of death-related thoughts rather than the direct emotional experience of fear or anxiety that drives the MS defenses (see Pyszczynski et al., 1999). In other words, TMT suggests that MS causes in- dividuals to (nonconsciously) engage in defense mechanisms that allow them to avoid existential anxiety. Before moving further with our discussion of the role of emotion in MS effects, it is important to define and discuss a few terms and issues concerning affective pro- cesses. We use the broad term “affect” to describe the moods/emotions that may be created by MS. This is to avoid the baggage associated with the terms mood and emotion.2 Affective states are often regarded as involving subjective experi- ence, changes in physiological arousal, and behavioral expressions. Decades ago, affective scientists realized that these responses do not intercorrelate highly (Lang, 1968). More recently, research has suggested that affective states can occur without conscious subjective experience (Winkielman & Berridge, 2004). The experience of anxiety, then, may refer to a state of physiological arousal that is not necessarily accompanied by self-reported anxiety/distress. Thus, the affective state evoked by MS may be unconscious or at least not verbalizable, but it may be measurable with physiological or behavioral assessments. Some evidence suggests that this may be the case. MS inductions do not pro- duce increases in self-reported negative affect, anxiety, or distress. In addition, self-reported affect is consistently found not to mediate the worldview defense in 1. TMT is a wide-ranging theory that addresses the many ways in which death- and self-awareness impact human culture, behavior, and attitudes. As such, TMT is not a single bounded theory but is a literature composed of numerous independent theories dealing with human mortality. Our review specifically and exclusively focuses upon elucidating the biological mechanism through which MS elicits cultural worldview defense. This is because this phenomenon has been the subject of comprehensive empirical and theoretical investigation. 2. Although psychological scientists who study affective processes often suggest that emotions and moods are distinct affective processes, Frijda (1986, p. 60) argued that the distinction between mood and emotion is “unsharp.” This is exemplified, for instance, by the fact that moods, which are viewed as differing from emotions in that they are longer in duration and have a less definite cause, may sometimes be of long durations but be associated with known triggers (see Frijda, 1993). ymjymj 线条 718 TriTT eT al. response to MS (e.g., Arndt, Allen, & Greenberg, 2001; Pyszczynski et al., 1999). Indeed, some studies have found an inverse relationship between the amount of death-related distress expressed and the extent of worldview defense observed (e.g., Greenberg, Simon, Harmon-Jones, Solomon, Pyszczynski, & Lyon, 1995). In one of only a few examinations of physiological responses, however, Arndt and colleagues (2001) found that following a subliminally presented MS prime, indi- viduals had greater muscle activity over their brows (corrugator muscle region). This is a psychophysiological correlate of increased negative affect, which suggests that mortality salience does induce physiologically experienced affect, though this did not mediate the effect of MS on cultural worldview defense. Greenberg and colleagues (2003) provided evidence that they argue confirmed that it is the potential for anxiety and not the actual experience of anxiety that leads to cultural worldview defense following MS. Participants who believed that they had been given a memory enhancing drug exhibited cultural worldview defense following MS, whereas those who thought that they had taken an antianxiety drug did not. This finding suggests that the effects of MS are reduced (or even elimi- nated) when participants do not believe that they are capable of experiencing anxi- ety. According to the authors, this substantiates the notion that it is the potential for anxiety and not anxiety itself that leads participants to defend their cultural worldview in response to MS. It should be noted, however, that expecting to take an antianxiety drug might actually reduce experienced anxiety due to the well- known placebo effect. Placebos, which modify participant’s expectations of their capacity to experience negative affect, have been found to alleviate symptoms of anxiety (e.g., see Clayton, Stewart, Fayyad, & Clary, 2006), depression (e.g., see Fournier et al., 2009), and pain (e.g., Benedetti & Amanzio, 1997). Recent func- tional neuroimaging research has suggested that placebo pills attenuate activation of neural processes associated with negative emotional responses to aversive vi- sual stimuli (Petrovic et al., 2005). Accordingly, Greenberg and colleagues’ (2003) findings may alternatively be interpreted as showing that the expectation of no anxiety created by labeling the pill influenced participants’ experienced affective state, which in turn, influenced MS effects. In sum, it seems that more evidence is needed to substantiate the notion, put forward by TMT, that it is the potential for and not the actual experience of anxiety that leads to cultural worldview defense following MS.3 The psyChologiCal meChanism of morTaliTy salienCe Defense: inTegraTing alTernaTive Theories Several alternative explanations have been put forward in recent years to account for the MS phenomenon. Taken together, these imply that cultural worldview de- fense is elicited by a general mechanism for dealing with a wide array of psycho- 3. Indeed, the only supporting evidence for the notion that cultural worldview defense is not mediated by self-reported negative affect relies on a null effect. Because any number of factors can cause a null effect, the lack of mediation does not provide strong evidence. This is particularly problematic because the measures used to assess cultural worldview defense are influenced by variables besides MS (e.g., pre-existing attitudes), which may negate its sensitivity to detect significant relationships with mediating variables. ymjymj 线条 WhaT’s so speCial aboUT DeaTh? 719 logical threats, associated with experienced rather than potential for anxiety per se, as has been hypothesized in the TMT literature. Misattribution of arousal, uncon- scious vigilance, cognitive dissonance, and uncertainty management, for instance, have all been suggested as psychological mechanisms, unrelated to death anxiety, which may underlie the MS effect. Misattribution of Arousal (Dutton & Aron, 1974; Schachter & Singer, 1962)—which occurs when individuals are induced to feel arousal and then falsely attribute such arousal to an unrelated activity—has been argued to underlie the MS effect (e.g., Proulx & Heine, 2008). Participants may misattribute their aroused state in re- sponse to MS to their positive or negative reactions to in-groups and out-groups, respectively, causing the cultural worldview defense phenomena. This seems par- ticularly plausible given that a distraction exercise is often administered follow- ing MS, which may distract participants from acknowledging the cause of their arousal (death anxiety). In support of the notion that misattribution of arousal plays a role in MS defense, research indicates that when participants are given external cues upon which they can misattribute their feelings, the effects of MS disappear (Goldenberg, Arndt, Hart, & Routledge, 2008). If it is the case that MS defense effects are attributable to misattribution of arousal, then this might suggest that experienced anxiety stem- ming from any threat—rather than the potential for death anxiety, specifically— should lead to cultural worldview defense, provided that individuals do not cor- rectly attribute their negative affect or arousal to the actual cause of the arousal. In support of this possibility, Proulx and Heine (2008) exposed participants to absurdist information that violated their expectations and found that this led to cultural worldview defense reactions. However, this effect only occurred when participants were not given an explanation of their arousal. This suggests, then, that the consequences of MS may be due to arousal that is not worked though, rather than death anxiety, specifically. In a similar vein, Holbrook, Sousa, and Hahn-Holbrook (2011) have suggested that cultural worldview defense may be caused by unconscious vigilance—a state of arousal initiated by alarm cues processed below the threshold of consciousness that heighten the intensity of reactions to positive and negative affective stimu- li. These researchers argue that MS-induced unconscious vigilance (rather than death anxiety, per se) leads to polarized perceptions of in-groups and out-groups. Support was found for this hypothesis in a series of four studies where MS led to biased judgments of sounds and images unrelated to cultural worldview, and where subliminal threats unrelated to death evoked cultural worldview defense (Holbrook et al., 2011). The reduction of cognitive dissonance (Festinger, 1957) may provide yet another explanation of MS defense. Cognitive consistency is an essential component of any cultural worldview. Some theorists (e.g., Jonas, Greenberg, & Frey, 2003) have accordingly argued that a cultural worldview may alleviate cognitive dissonance, an aversive mental state that occurs when one’s expectations have been violated (Festinger, 1957). MS may cause feelings of dissonance between an individual’s behavior, which tends to serve long-term goals, and the realization that life could end at any instant. This dissonance may cause individuals to engage in world- view-consistent cognitions and behaviors as a means of reducing the dissonance. In other words, MS might arouse cognitive dissonance and worldview defense might act to relieve dissonance. 720 TriTT eT al. In sum, a number of theories suggest that more general psychological mech- anisms than those articulated by TMT, associated with experienced rather than potential anxiety, may function to produce the MS/cultural worldview defense phenomenon. If this is the case, then psychological threats besides death anxiety should elicit cultural worldview defense. Although some studies have indicated that cultural worldview defense is elicited in response to death anxiety but not other anxiety-producing stimuli such as thoughts of physical pain, worries about life after college, or failing an exam (e.g., Greenberg, Pyszczynski, Solomon, Si- mon, & Breus, 1994; Greenberg, Simon, Harmon-Jones, et al., 1995), these stimuli may not be sufficiently troublesome and at the right level of unconsciousness to provide a good comparison for the effects of MS. It may be that a stimulus needs to be sufficiently anxiety provoking and at the right level of unconsciousness in order to incite a state of unconscious vigilance/arousal that motivates defensive reactions. Much research into the effects of affective states on other perceptions and judgments has revealed that consciousness of the source of the affective state and/or the affective state itself can eliminate the direct effect of the affective state on the perception/judgment (Berkowitz, 2000). Indeed, other studies that have compared the effects of MS to threats to other salient psychological needs have suggested that cultural worldview defense may not be specific to death anxiety. Threats to psychological needs such as certainty (e.g., McGregor, Zanna, Holmes, & Spencer, 2001; van den Bos, 2001), meaning (Proulx & Heine, 2008; Proulx, Heine, & Vohs, 2010; Randles, Proulx, & Heine, 2011; Simons & Rensink, 2005), affiliation/attachment security (Baumeister & Leary, 1995; Hart, Shaver, & Goldenberg, 2005), faith in the social system (e.g., Jost & Banaji, 1994; Lerner, 1980), and personal control (Kay, Gaucher, Napier, Callan, & Laurin, 2008; Whitson & Galinsky, 2008)—like MS threats—have all been found to evoke cultural worldview defense. Accordingly, some researchers have argued that a psychological need other than to buffer death anxiety may represent the prime mover of human behavior that underlie responses to MS (e.g., Hart et al