Latent inhibition and recall/recognition of irrelevant stimuli as a function of pre-exposure duration in high and low psychotic-prone normal subjects.

Learning to ignore non-relevant stimuli (coloured geometric shapes) was evaluated in high and low psychotic-prone normal subjects in two experiments. In the first, subjects were tested in a latent inhibition paradigm in a 2 x 2 x 3 factorial design (high vs. low psychotic proneness, as measured by MMPI subscales; pre-exposure of the stimuli such that they were non-relevant before the test but relevant in the test vs. absence of such pre-exposure; three levels of pre-exposure duration: 3-, 6- and 15-min). Low psychotic-prone subjects showed the latent inhibition effect (poorer learning as a result of pre-exposure to the non-relevant stimuli as compared to no pre-exposure) at 6- and 15-min durations, but not at 3-min. High psychotic-prone subjects failed to show latent inhibition at 3- and 6-min durations, but did show the effect at 15-min. The second experiment employed a 2 x 3 design (high vs. low psychotic proneness; three levels of pre-exposure duration of the same stimuli used in Expt 1). High psychotic-prone normal subjects recalled and recognized more previously non-relevant stimuli than low psychotic-prone subjects, particularly after 6-min pre-exposure to those stimuli. The data of the two experiments suggest that the attenuation of latent inhibition in high psychotic-prone subjects as compared to low psychotic-prone subjects is a result of the increased attention to non-relevant information.