EXPRESS: 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 conditioned inhibition and occasion setting 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 (Carver & White, 1994) and 4) Barratt Impulsivity (Patton et al., 1995) 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 whilst there may be superficial similarities between these different forms of inhibition they are likely to have different substrates.