An exploration of relationships between associative and non-associative measures of inhibition.

Conditioned inhibition and occasion setting are two examples of inhibitory associative phenomena that have traditionally been studied in isolation from non-associative inhibition. Non-associative inhibition has been assessed using a variety of measures (e.g., stop signal reaction time and impulsivity questionnaires) and weak non-associative inhibition has been linked to a variety of disorders including addiction. However, even though both associative and non-associative inhibition have a common core-both involve suppression of behaviour, there has been relatively little study of potential relationships between these different forms of inhibition. In the current investigation, we carried out exploratory analyses to look for possible links between associative inhibition and four non-associative measures of inhibition, namely, (1) stop signal reaction time, (2) delay discounting, and scores on (3) the Behaviour Inhibition System/Behaviour Activation System and (4) Barratt Impulsivity questionnaires. Despite the fact that we carefully selected data to minimise noise in the measurement of associative inhibition, we found no clear evidence of links between associative and non-associative inhibition. We therefore conclude that while there may be superficial similarities between these different forms of inhibition they are likely to have different substrates.