Hibbing et al. present persuasive research linking threat sensitivity to conservative political beliefs. Yet further study into the possible confound between negative valence and arousal is needed before it can be affirmed that negative valence, rather than arousal more generally, underlies the psychological motivations to endorse conservative political belief.

Arousal and valence have often been confounded. For decades, psychologists have assumed that humans have a negativity bias, responding more intensely to negative than to positive and/or neutral information (e.g., Baumeister et al. Reference Baumeister, Bratslavsky, Finkenauer and Vohs2001; Cacioppo et al. Reference Cacioppo, Gardner and Berntson1999; Öhman Reference Öhman, Campbell, Haynes and Richardson1992; Smith et al. Reference Smith, Cacioppo, Larsen and Chartrand2003). However, some of the support for such a bias may have come from the use of positive stimuli that are low in arousal (e.g., scenes of leisure activities) instead of stimuli that are high in arousal (e.g., erotica). Indeed, recent psychophysiological studies that have used positive and negative stimuli with the same mean arousal ratings, have found equally enhanced attention to positive as well as negative compared to neutral images (e.g., see Weinberg & Hajcak Reference Weinberg and Hajcak2010).

Political psychology research may have similarly confounded valence and arousal, leading to the false conclusion that negative valence per se is associated with conservative political beliefs. The confounded nature of arousal and valence is reflected in Hibbing et al.'s interpretation of experimental, psychophysiological, neurobiological, and personality research.

For example, Hibbing et al. cited experimental studies that supported the idea that threat leads to conservative shifts in political beliefs. However, most of the studies referenced neglected to assess the impact of non-negative forms of arousal. Could positively-arousing stimuli lead to similar conservative shifts? It is premature to conclude that negative valence causes conservative shifts when the impact of positively valenced arousing stimuli has not been assessed. Hibbing et al. reviewed only one experimental study that included positively valenced stimuli, happy faces (Lodge & Taber, Reference Lodge and Taber2013). Yet because happy faces have elsewhere been found to be less motivationally salient/arousing than unhappy/angry faces (e.g., Hansen & Hansen Reference Hansen and Hansen1988), it remains unclear whether valence or arousal underlie such findings.

Citing the relevant psychophysiological research, Hibbing et al. similarly concluded that conservatives preferentially process negative information, even though the studies they considered did not include an arousing, non-negatively valenced condition. Instead, researchers either assessed how individuals process negative compared to neutral information (Dodd et al. Reference Dodd, Balzer, Jacobs, Gruszczynski, Smith and Hibbing2012; Fodor et al. Reference Fodor, Wick, Hartsen and Preve2008; Oxley et al. Reference Oxley, Smith, Alford, Hibbing, Miller, Scalora, Hatemi and Hibbing2008; Smith et al. Reference Smith, Oxley, Hibbing, Alford and Hibbing2011) or how participants processed highly arousing negative compared to less arousing positively valenced information, thus confounding the effect of arousal and valence (Carraro et al. 2011; Dodd et al. Reference Dodd, Balzer, Jacobs, Gruszczynski, Smith and Hibbing2012; McLean et al., in press). Dodd et al., for example, used three photographic stimuli of each valence type; positive stimuli included depictions of a happy child, a bowl of fruit, and a cute rabbit, whereas negative stimuli included depictions of a spider walking across a man's face, an open wound infested with maggots, and a violent altercation between a man and a group of people. Without the engagement of equally arousing positive and negative stimuli, findings in these studies remain questionable.

Hibbing et al. also cited studies that documented enhanced volume and activity of the amygdala among conservatives as support for their greater sensitivity to threat and uncertainty (Kanai et al. Reference Kanai, Feilden, Firth and Rees2011; Schreiber et al. Reference Schreiber, Fonzo, Simmons, Dawes, Flagan, Fowler and Paulus2013. Yet, recent evidence suggests that the amygdala is implicated in detecting a broad range of motivationally relevant stimuli, including positive rewards (Cunningham Reference Cunningham2012; Murray Reference Murray2007). Thus, enhanced amygdala activity/volume may reflect heightened motivational arousal, in general, rather than specific sensitivity to threat and uncertainty.

Additionally, if political conservatism is fundamentally associated with sensitivity to negative valence specifically, then it should be at least somewhat positively correlated with neuroticism, a personality trait that clearly subsumes fear, anxiety, and aversion to uncertainty (e.g., Hirsh & Inzlicht Reference Hirsh and Inzlicht2008). Neuroticism, however, has not been linked in any consist manner to political belief (e.g., Hirsh et al. Reference Hirsh, DeYoung, Xu and Peterson2010).

In fact, the personality research cited by Hibbing et al., which indicates that conservatism is linked with intolerance of uncertainty, may arguably be interpreted to indicate intolerance of arousal rather than threat. Uncertainty or novelty is not always experienced as aversive, and is just as likely to activate the dopaminergic exploratory systems as the threat/anxiety system (Gray Reference Gray1982). Moreover, uncertainty or novelty can intensify the impact of positive as well as negative emotional events (see Bar-Anan et al. Reference Bar-Anan, Wilson and Gilbert2009).

Not only is it conceivable that the effects of arousal and valance have been confounded in past studies but there are compelling reasons independent of these studies to believe that conservatism is motivated by arousal rather than by valance. Lines of research have recently indicated a link between conservative political belief and positive emotional states such as happiness (e.g., Taylor et al. Reference Taylor, Funk and Craighill2006). Moreover, although a negative valence model would suggest that conservative political parties are most likely to be voted into power during times of instability, recession and threat, historically, this has not always been the case. Extreme right-wing political parties such as Denmark's Folk party and Norway's Progress Party, for example, rose to power during the boom years of the mid-2000s, when unemployment hovered around only 5% in both countries. A review of studies examining economic influences on voting behavior provides similar evidence: Societies become more conservative in times of economic boom, rather than recession (Monroe Reference Monroe1979). In addition, premarital and unconventional sex, sexually explicit literature and representation, and recreational drug use, although typically decried by conservatives (Dombrink Reference Dombrink2006), are not obviously fear- inducing but rather appear to be more accurately construed as arousing. Finally, we have recently demonstrated that positive, like negative mood induction, can lead to conservative shifts in belief preference (Tritt et al. Reference Tritt, Peterson and Inzlicht2013).

In short, it is reasonable to conclude that arousal, regardless of valence, may underlie conservative shifts in political beliefs, and to posit that conservatives are more sensitive to arousing stimuli than to threat, per se. At the very least, further research is needed to distinguish the effects of arousal and valence before it can be definitively concluded that differences in negativity bias underlie variations in political ideology.