Latent Inhibition in Humans: Single-Cue Conditioning Revisited

Latent inhibition in human Pavlovian conditioning was assessed by way of autonomic responses. In Experiment 1 (N = 72), three pairs of conditioning and control groups were preexposed to 0, 10, or 20 to-be-conditioned stimuli (to-be-CSs), respectively. Acquisition of electrodermal first-interval and heart rate response conditioning were detectable only in the zero preexposure condition. However, 20 preexposures were needed for latent inhibition of vasomotor response conditioning. In Experiment 2 (N = 48), preexposure to the to-be-CS was compared with preexposure to a stimulus that was not presented during subsequent acquisition. CS preexposure completely abolished electrodermal first-interval and heart rate response conditioning. Although vasomotor conditioning was not affected by preexposure, latent inhibition of second-interval electrodermal response conditioning was obtained. Taken together, the data from both experiments provide clear evidence for latent inhibition in human Pavlovian conditioning.