Acoustic Startle Response in High and Low Hostiles Before And After A Cold Pressor Task

High-hostiles exhibit exaggerated physiological responses to stressors as seen by increased cardiovascular reactivity (BP & HR) (Rhodes, Harrison, & Demaree, 2002; Demaree & Harrison, 1997). This exaggerated physiological response style is associated with cardiovascular disease and premature death (Everson et al., 1997). This experiment hypothesized that diminished regulatory control would also be evident in the Acoustic Startle Response (ASR). In this experiment, high- and low-hostile undergraduate men (N = 40) were exposed to a series of startle probes before and after a cold pressor (CP). Startle responses were measured using electromyography (EMG) recorded over the orbicularis occuli. Cardiovascular measures of blood pressure and heart rate were also taken. A 2 X 2 mixed factorial ANOVA was performed with Group (high and low hostile) as the fixed factor, Condition (pre and post CP) as the repeated measure, and peak magnitude EMG (mV) of startle responses as the dependent variable. For startle responses, significant main effects for Group and Condition indicated that high hostiles had larger startle responses than low hostiles and startle responses decreased after the cold pressor (CP). A significant Group X Condition interaction effect was found. Post-hoc analyses revealed no significant group differences before the CP. After the CP, high-hostiles had significantly higher startle responses than-low hostiles. High-hostiles' startle responses did not change significantly after the CP, whereas low-hostiles' startle response magnitude decreased significantly after the CP. Low-hostiles HR increased significantly after the cold pressor and both groups SBP decreased significantly after the cold pressor.