A novel test of conditioned inhibition correlates with personality measures of schizotypy and reward sensitivity

Conditioned inhibition is demonstrated when the meaning of one signal (conditioned stimulus, CS) is qualified by another (conditioned inhibitor, CI). Whilst the CS presented alone reliably predicts the outcome (unconditioned stimulus, US), when presented in conjunction with the CI the otherwise expected US will not occur. Conditioned inhibition has long been established in animal research but there have been difficulties in establishing reliable procedures suitable for use in human research. Such procedures are necessary to investigate disorders in which cognitive inhibitory mechanisms are known to be deficient, e.g., schizophrenia. In healthy participants, individual differences in the tendency to show conditioned inhibition should be related to personality measures of cognitive inhibition. In the present study, this was measured using an automated test procedure, in which visual stimuli predict the occurrence or non-occurrence of a visual outcome US, and BIS/BAS and schizotypy scales.Conditioned inhibition was reliable across two alternative test variants, in which the non-occurrence of the US was specified differently, and was confirmed by summation tests. The level of CI shown was positively associated with BAS Reward Responsiveness but did not correlate significantly with any of the other BIS/BAS scales. Conversely, the level of CI shown was negatively associated with schizotypy. We suggest that this novel conditioned inhibition task should now be applied to investigate a range of disorders that have some basis in dysfunctional inhibitory processes, such as schizophrenia.