Adult residents of Lincoln, Nebraska who differed in terms of their political views were administered two tasks that are commonly used to gauge threat sensitivity. In one task, participants viewed threatening images (e.g., of spiders, bloody faces, and rotten food), in comparison with neutral and positive images, while the experimenters measured their skin conductance responses (SCR). Heightened SCR reflects increased sweat gland activity associated with a sympathetic nervous system response that is characteristic of fear. As hypothesized, participants who held right-wing (vs. left-wing) views exhibited significantly larger SCRs in response to these threatening images, whereas SCRs to neutral and positive images were uncorrelated with political views. This pattern remained statistically significant after adjusting for the effects of age, gender, education, and income.
Second, Oxley et al. (2008) examined the defensive startle reflex, which was indexed in terms of the magnitude of participants eyeblink in response to a very loud and unexpected burst of white noise while they viewed a fixation cross on a computer monitor. Stronger contraction of the muscle surrounding the eye (oribularis oculi) indicates a stronger reflexive defensive reaction to the startling event. All participants exhibited the typical eyeblink reflex in response to the noise burst, but this defensive reaction was significantly stronger for participants who held right-wing (vs. left-wing) views, after adjusting for age, gender, and socioeconomic status.