Effects of addiction science on conceived freewill and responsibility

Although there is speculation that medicalization of addiction undermines conceived agency, only relatively modest effects have been reported. Research participants generally have ideas about addiction that are informed both by personal experience and by media, and their views may not be wholly updated in response to study-information. Here we examine the potential impact of addiction science theories on perceived volition and responsibility by considering the issues in the context of a hypothetical new drug, "Z." Participants (N = 662) were provided one of three functional accounts that each corresponded to a prominent theory within addiction science: incentive-sensitization, impaired self-control, and habit-system dominance. For half of participants, additional neuroscience mechanism information was included with the functional account. Across explanations, the inclusion of mechanism information was associated with significantly less perceived volition and marginal reduction in blame, For several measures, there was a significant or marginally significant interaction between which addiction explanation was used and whether mechanism information was included, with mechanism generally having the largest impact given the impaired self-control explanation of addiction and little evidence of impact given the incentive-sensitization explanation of addiction. Taken together, these results suggest robust effects of addiction science on judgments of agency when presented in the context of a novel addiction. It is unclear whether a sustained scientific consensus around an existing theory could produce a similar impact on how people understand real addictive behavior.