Kicking the habit: Why evidence for habits in humans might be overestimated

Researchers typically classify behavior as habitual if it occurs independently of changes in the value of its outcomes (revaluation test) or the impact it has on those outcomes (contingency degradation test). We argue that these tests are valid only if they (a) are sufficiently sensitive and (b) target the outcomes that might actually control behavior. These criteria resemble the sensitivity and information criteria that are widely adopted in research on learning without awareness. We argue that past and future evidence for habits should be evaluated in light of these criteria and illustrate this approach by applying the information criterion to the studies conducted by de Wit et al. (2007, 2013). In three experiments that were modelled after these studies, we used alternative revaluation and contingency degradation tests that targeted other outcomes than those targeted in the original studies. These alternative tests consistently provided evidence for knowledge of outcomes that could have controlled seemingly habitual behavior. Our results suggest that the revaluation test used by de Wit et al. (2007, 2013) did not meet the information criterion, which questions the validity of their conclusions regarding the habitual nature of the observed behavior.