Abstract
The behavioral immune system (BIS) is a suite of psychological mechanisms that cause individuals to avoid encountering pathogens. The BIS has been linked to socially conservative attitudes, outgroup bias and conformity to social norms. The potential role of the BIS in political polarization has yet to be explored. The present research filled this gap by partially replicating and extending a study by Van Boven, Ehret, & Sherman (2018). Like those authors, we found that while most Republicans and Democrats alike accepted climate change science as fact, the political party ostensibly proposing a climate change policy can significantly influence level of support for implementing it – that is, an ingroup-outgroup effect. In addition, we examined the role of the BIS – measured by the Perceived Vulnerability to Disease scale (PVD; Duncan, Schaller, & Park, 2009) – in producing this effect, taking into account two other potential moderators: Belief in a Dangerous World (BDW; Altemeyer, 1988) and Need for Closure (NFC; Webster & Kruglanski, 1994; Roets & Van Hiel, 2011). In addition, we experimentally tested whether priming participants to think of their immunity to diseases would reduce the ingroup-outgroup effect on climate change policy support relative to controls. We were able to replicate Van Boven et al.’s (2018) findings. In addition, although we found that PVD predicted the ingroup-outgroup effect, it was in the opposite direction to that hypothesized; greater PVD was associated with stronger participant support for climate policies proposed by their political outgroup than their ingroup. This effect remained when BDW and NFC were controlled. Potential explanations for these unexpected findings are discussed.