Cardiac defense response as a predictor of fear learning.

Prior studies have demonstrated that differences in activation of the defensive motivational system - as indexed by cardiac responses to the CS+ during aversive conditioning - are related to differences in the acquisition of two-levels-of-learning: cognitive (contingency learning) and emotional (fear learning). Here we further explored these differences using an independent psychophysiological test to assess cardiac reactivity - Cardiac Defense Response (CDR) - prior to the aversive conditioning task. Participants were then classified as accelerators or decelerators based on the CDR second accelerative component. Both groups showed contingency learning, as indexed by greater skin conductance changes to CS+ than to CS- during acquisition and by consistent contingency awareness ratings after the conditioning task. However, only accelerators showed affective fear learning, as indexed by greater blinks to CS+ than to CS- during (acquisition) and after (extinction) aversive conditioning. These results extend evidence about differences in the two-levels-of-learning in aversive conditioning as a function of defensive reactivity, and suggest that the CDR second accelerative component could be a reliable predictor of fear learning.