Consider the following passage:

At first blush, this summary of the literature seems couched in scientifically impartial language. Yet, a moment's reflection reveals that this passage could just as readily been worded as follows:

Carraro et al.'s choice of conservatives' rather than liberals' personality as the explanandum may appear inconsequential. Nevertheless, the question of how to conceptualize differences in political ideology may hold largely unappreciated implications for the conduct and interpretation of research in personality and clinical psychology.

In their incisive article, Duarte et al. lay bare the troubling scientific ramifications of political uniformity for social psychology. I extend Duarte et al.’s important arguments by examining the implications of this lack of political diversity for a problem they did not explicitly address – namely, the framing of findings in two fields allied with social psychology: personality and clinical psychology (see also Groeger Reference Groeger2011).

Over the past several decades, researchers have demonstrated that conservatives and liberals differ in sensitivity to threat (Hibbing et al. Reference Hibbing, Smith and Alford2014; Jost et al. Reference Jost, Glaser, Kruglanski and Sulloway2003) and openness to experience (Carney et al. Reference Carney, Jost, Gosling and Potter2008), with conservatives being higher in the former and lower in the latter. The assertions of some writers to the contrary (Ferguson Reference Ferguson2012), these differences are robust, replicable, and generalizable across diverse samples (Hibbing et al. Reference Hibbing, Smith and Alford2014).

Although these differences are value-free, they have commonly been framed by researchers as reflecting poorly on conservatives. For example, conservatives' higher sensitivity to threat relative to liberals' has frequently been portrayed as reflecting “negativity bias” (Hibbing et al. Reference Hibbing, Smith and Alford2014) or “motivated closed-mindedness” (Thórisdóttir & Jost Reference Thórisdóttir and Jost2011), and conservatives' lower levels of openness to experience relative that of liberals has been portrayed as reflecting a reliance on “system-justifying ideologies” (Jost & Hunyady Reference Jost and Hunyady2005).

Furthermore, many authors who have examined the personality correlates of political ideology have framed them in terms of explaining the sources of conservatives', rather than liberals', political ideology, thereby implying inadvertently that only the former necessitates explanation. As exemplified by such book titles as The Republican Brain (Mooney Reference Mooney2012b), these writers have often treated conservatives as the reference class and liberals as the comparison class. For example, although Jost et al. (Reference Jost, Glaser, Kruglanski and Sulloway2003) maintained that political conservatism is rooted partly in a desire to satisfy certain “psychological motivational needs” (p. 340), they did not address the possibility that political liberalism stems from different emotional needs. Similarly, the “negativity bias” of conservatives, which appears to reflect their heightened threat sensitivity (Lilienfeld & Latzman Reference Lilienfeld and Latzman2014), can just as validly be conceptualized as a “bias away from threat” on the part of liberals.

The one-sided framing of liberal-conservative differences neglects research suggesting that high and low levels of most, if not all, personality traits are neither inherently maladaptive nor adaptive. Instead, extremes on both poles of these traits probably entail differing trade-offs (Nettle Reference Nettle2006). For example, although high levels of threat sensitivity are tied to risk for certain anxiety disorders and other internalizing disorders (Nelson et al. Reference Nelson, McGowan, Sarapas, Robison-Andrew, Altman, Campbell, Gorka, Katz and Shankman2013), these trait levels may be adaptive in circumstances of high objective danger, such as the gathering storm clouds of war. Conversely, although low levels of threat sensitivity are tied to risk for psychopathic personality and other externalizing conditions, such as conduct disorder (Patrick et al. Reference Patrick, Fowles and Krueger2009), these trait levels may predispose to adaptive risk-taking and perhaps prosocial altruism (Smith et al. Reference Smith, Lilienfeld, Coffey and Dabbs2013). Trade-offs may also be evident for extremes on the dimension of openness to experience. Although high openness to experience is associated with heightened creativity and artistic accomplishment (Li et al. Reference Li, Li, Huang, Kong, Yang, Wei, Li, Cheng, Zhang, Qiu and Liu2015), it is also associated with elevated levels of schizotypy and paranormal beliefs (Kwapil et al. Reference Kwapil, Barrantes-Vidal and Silvia2008). On the flip side of the coin, low openness to experience is linked to high levels of rigidity, authoritarianism, and perhaps prejudice (Cullen et al. Reference Cullen, Wright and Alessandri2002), but it may also be linked to better reality contact and a relative immunity to psychotic ideation.

Moreover, many individuals on both poles of personality dimensions may seek out and occupy certain “ecological niches” (Hutchinson Reference Hutchinson1978) in which their dispositions facilitate adaptation. For example, individuals with low openness to experience may thrive in occupations marked by a high need for structure, such as tax law, whereas individuals with high openness to experience may thrive in largely unstructured occupations, such as literature.

A nuanced and comprehensive understanding of personality requires researchers to appreciate that individual differences are rarely adaptive or maladaptive per se, but are associated with both advantages and disadvantages as a function of still poorly understood moderating variables, including other personality variables and situational factors. The lack of political diversity in psychology may contribute to a one-sided perspective that implicitly regards extremes in certain individual differences as inherently maladaptive. As a consequence, psychologists have accorded insufficient attention to (a) personality dispositions associated with liberalism and (b) the potential advantages of high threat sensitivity and low openness to experience, thereby impeding our understanding of the relations between personality and ideology on both ends of the political spectrum.

As Duarte et al. observe, most psychologists appear to be politically liberal. Because most of us are blind to the existence of our psychological blind spots (Pronin et al. Reference Pronin, Lin and Ross2002), many psychologists may be largely oblivious of the extent to which their political biases subtly shape their framing of research on political ideology.