Pavlovian conditioned diminution of the unconditioned SCR using unpleasant stimuli as the unconditioned stimulus

In this study, we investigated the possibility of obtaining conditioned diminution of the unconditioned skin conductance response (SCR) in humans using as unconditioned stimulus (US) the simultaneous presentation of an unpleasant picture and a sound. Although initial reactivity to the stimuli was similar in the experimental and control groups, after the acquisition phase, conditioned response (CR) and unconditioned response (UR) diminution were both observed. These results reveal the possibility of obtaining UR diminution by substituting the traditional aversive USs (bursts of white noise and electric shocks) with stimuli whose aversiveness derives from their semantic content more than from their intensity.