Trials-to-criterion latent inhibition in humans as a function of stimulus pre-exposure and positive-schizotypy.

Latent inhibition (LI) is a phenomenon during which non-reinforced pre-exposure to a stimulus retards later learning of associations with that same stimulus. It has been suggested that LI is a positive function of the amount of stimulus pre-exposure (PE) and that with very small amounts of PE, facilitation rather than inhibition will occur-particularly in high positive-schizotypes. Although LI has been demonstrated as a function of the amount of pre-exposure in animals, human findings have not proved to be so uniform or consistent. The primary objective of the present study was to establish LI as a function of numbers of pre-exposure on visual and auditory trials-to-criterion tasks, with a secondary objective to establish latent facilitation (LF) with very low numbers of pre-exposure in high positive-schizotypes. Results revealed a uniform pattern of learning across pre-exposure conditions, including latent facilitation, on the visual, but not the auditory task. LF was also observed in the high, but not low, scorers in positive-schizotypy with very low numbers of pre-exposure on the visual task.