Latent inhibition (LI) refers to the phenomenon of reduced conditioning seen after nonreinforced stimulus preexposure. Animal studies of LI typically employ a between-subject procedure to demonstrate LI. In such procedures, one group of subjects is preexposed (PE) to the to-be-conditioned stimulus (CS), whereas another group of subjects is not preexposed (NPE). The CS is subsequently paired with an unconditioned stimulus (US). LI is measured by the difference in some index of learning (e.g., conditioned fear) of the CS–US association between the PE and NPE groups, and is manifested as poorer learning in the PE group. As detailed in several chapters in the present volume by Weiner, Lubow, Kumari and Ettinger, Escobar and Miller and others, a number of theories have been put forward to explain LI as a form of learned inattention in which subjects learn to ignore or reduce attention to irrelevant stimuli (Lubow,1989). LI has also been characterized as a form of proactive interference in which the inattentional response (acquired as a consequence of a “CS–no-consequence” association) interferes with, or competes for, the expression or retrieval of the conditioned response (resulting from an effective CS–US association) (Miller & Escobar, 2009; Weiner, 1990, 2003, 2009).

Deficits in attention and information processing are central features in schizophrenia, and these deficits may lead to stimulus overload, cognitive fragmentation and thought disorder common in this disorder (Freedman et al., 1991; Perry et al., 1999; Strauss et al., 1993).