Appetitive latent inhibition in rats: now you see it (sign tracking), now you don't (goal tracking).

Latent inhibition (LI), the retardation of Pavlovian acquisition after nonreinforced preexposure to the conditioned stimulus, is a popular paradigm for studying basic attentional and memory processes from both behavioral and neurobiological perspectives. It is argued that whether LI emerges depends on the behavioral measure used to index conditioning. An experiment with rats demonstrates that stimulus preexposure retards the development of sign-tracking responses directed at the stimulus, but not the development of goal-tracking responses directed at the site of food delivery. These results are consistent with models that explain LI in terms of a deficit in retrieval.