Latent inhibition in smokers vs. nonsmokers: interaction with number or intensity of preexposures?

Latent inhibition (LI) refers to the slowing of learning about a stimulus after preexposure, i.e., previous presentation of the stimulus without any consequence. This report summarizes results of four studies investigating the effect of being a smoker or nonsmoker on auditory LI as a function of procedural parameters, namely number (10 vs. 30) and intensity (low vs. high) of preexposed stimuli. In general, the number of preexposures did not affect LI, whereas low-intensity stimuli led to greater LI than high-intensity stimuli. These findings underline the importance of automatic vs. controlled processing of the preexposed stimuli for the development of human LI. Smokers showed increased LI compared to nonsmokers in low-intensity task versions as well as compared to both smokers and nonsmokers in high-intensity versions. These findings may indicate that nicotinic effects on LI depend on the robustness of LI in the control group.