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. Author manuscript; available in PMC: 2019 Apr 1.
Published in final edited form as: Pain. 2018 Apr;159(4):699–711. doi: 10.1097/j.pain.0000000000001132

Figure 2.

Figure 2

Theoretical process models. (A) Mediation model, in which the effect of stimulus temperature on the Autonomic Nervous System (ANS) response is statistically mediated by pain intensity. (B) Mediated Moderation model, in which the interaction effect between stimulus temperature and categorization in predicting the ANS response is statistically mediated by the interaction between stimulus categorization and intensity (experienced warmth or pain). In the mediation model, path c represents the overall effect of temperature on the ANS response, a represents the effect of temperature on intensity, b represents the effect of intensity on the ANS response, and c′ represents the direct effect of temperature on the ANS response, while subtracting the multiplicative indirect effect of temperature through intensity on the ANS response (path ab). In the mediated moderation model, paths represent the interaction effects of these model variables with the moderator stimulus categorization (nonpainful vs. painful). Individual-level models (i) are aggregated to the group-level using non-parametric bootstrapping.