Effects of Differentially Modeled Stimuli on Vicarious Autonomic Arousal

Abstract

The present study examined effects of variations in modeled pain cues on level of vicarious arousal, using heart rate and blood-volume amplitude as psychophysiological measures. Students were assigned randomly to one of four groups in which they either (a) underwent directly the cold-pressor test, (b) observed a model exposed to the cold-pressor test and expressing pain by facial and bodily movements, (c) heard only the modeled verbal expressions of pain, or (4) observed the model express neither verbal expressions nor physical movements while undergoing the painful stimulation. The results show aversive stimulation increases heart rate whereas vicarious aversive stimulation produces reductions in heart rate. The deceleration of heart rate was not found in response to all three forms of modeling. Both direct and vicarious aversive stimulation produced decreases in the amplitude of vasomotor responses. The size of the decrement between direct stimulation and the minimal modeling condition of vicarious arousal showed significant differences, but differences between direct stimulation and the maximal modeling condition were not significant. The vasoconstriction was found in response to two forms of modeling.

Autonomic Arousal And Experimentally Induced Pain: A Critical Review of the Literature

“…Across the lifespan, cold pressor stimulation increased cardiovascular response when compared with baseline (27,(30)(31)(32)(33), warm pressor (34) and vicarious experience (35). Additionally, imagery-based distraction (28) and odourant administration (36) diminished vasoconstriction and blood pressure responses to cold pressor while simultaneously increasing pain tolerance and decreasing pain report, although greater sensory input from odourant administration may have increased heart rate.…”

“…When studies used truly uniform and painful stimuli, they generally found significant results for autonomic response (30,(32)(33)(34)39,57,58,61,62,66). Despite the potential influence of anxiety or fear of upcoming noxious stimulation, or the influence of being in a novel laboratory environment, only four studies reported waiting for stable autonomic activity before painful stimulation began (27,31,38,61), with seven other studies including prestimulation adaptation periods lasting 10 min or longer (33,35,41,44,45,49,51). Similarly, studies administering stimulation more than once differed from seconds to days in their interstimulus intervals.…”

“…Design issues: The majority of the studies reviewed failed to distinguish stimulus-specific response patterns by examining painful stimuli alone. Although eight studies did make comparisons with other stimuli, only some comparative stimuli were informative: slides of homicide victims (43), arithmetic and projective test stressors (44), warm pressor (34,37), maximum inspiratory breath hold (61) and vicarious experience (35).…”

“…Investigations assessing responses for brief, selected durations may have missed patterns of responding occurring outside of measurement periods such as differences in autonomic responding reported in investigations that included poststimulation assessment (4,23,28,30,33,42,56,62). In grouping autonomic responses measured continuously for extended periods into average values without accounting for habituation (35,43,51,52), however, studies could have missed important patterns of responding because other studies offered evidence that habituation occurred in response to repeated stimulation (23,47,50,53,55).…”

“…Smaller samples can be appropriate when studying a larger effect, but the studies reviewed with smaller sample sizes offered no justification for sample size, which reduces power and impairs interpretation of nonsignificant results. Only six studies reviewed (4,27,36,38,42,54) included a sample of ≥74 participants, and seven studies had groups with as few as 10 participants (30,33,35,41,49,50,59). Furthermore, many researchers presented nonsignificant findings as evidence of no effect, which is faulty logic in a null hypothesis testing paradigm, and only six studies reviewed reported statistics regarding effect size to offer insight into the clinical or practical utility of findings (27,29,42,47,48,54).…”