1 THE AUTONOMIC PHYSIOLOGY OF TERROR MANAGEMENT ...

stimulation in dogs has been shown to buffer the effects of sympathetic stimulation on
heart rate (e.g., Levy, 1990) and in humans vagal influence on the heart appears to
override sympathetic influence on the heart (e.g., Uytdehaage and Thayer, 1989). Greater
tonic vagal tone also predicts protection from other physiological threat responses, such
as the eye-blink startle response and defensive cardiac patterns in response to various
stimuli (Ruiz-Padial, Sollers, Vila, and Thayer, 2003; Thayer, Friedman, Borkovec,
Johnsen, & Molina, 2000).
Psychological Parallels
In addition to these similar physiological correlates supportive of the hypothesis
that self-esteem promotes vagal tone, research links both self-esteem and vagal tone to
threat-related psychological experiences. Lower state self-esteem and insecure self-
esteem predict more psychological defensiveness, less anxiety, and less hostility (e.g.,
Schimel, Arndt, Pyszczynski, & Greenberg, 2001; Greenberg et al., 1992; Kernis,
Grannemann, & Barclay, 1989). Further, low state and/or insecure self-esteem has been
linked to depressed affect, particularly as it relates to concerns about the self, for
example, as a consequence of failure or as manifested in suicidality (de Man and
Gutierrez, 2002). Similarly, state decreases in vagal tone and/or insecurity of vagal tone
predict the experience of threat-related psychological responses. Vagal withdrawal or a
propensity for vagal withdrawal predicts various anxiety-related experiences and hostility
(e.g., Mauss, Wilhelm, & Gross, 2001; Thayer, Friedman, & Borkovec, 1996; Sloan,
Shapiro, Bigger, Bagiella, Steinman, & Gorman, 1994). Further, as with self-esteem, low
vagal tone or insecure vagal tone predicts depression particularly when tied to concerns
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