Scholarly publishing plays a key role in disseminating scientific and technical knowledge and driving innovation. This paper argues that to manage the transition to the Open Access (OA) model of scholarly publishing we need to understand better what enables, encourages and inhibits the adoption of OA publishing among scientists, and to appreciate individual differences within disciplines. The study adopts a psychological perspective to elucidate motivations, capabilities and opportunities for OA publishing among bio-scientists in the UK. To identify individual differences within the discipline we interview bio-scientists with starkly different past practices for disclosing research data and technologies. Content analysis of the interview data reveals that the sampled bio-scientists face similar obstacles and enablers in their physical environment, but that their motivations and experience of their social environments differ. One group is strongly motivated to adopt OA publishing - mainly by their moral convictions and beliefs that OA benefits themselves, other scientists and society - and feels peer pressure related to OA. The other group expresses fewer pro-OA beliefs, holds beliefs that are demotivating towards adoption of OA publishing, but feels pressure from research funders to adopt this form of publishing. Our quantitative analysis reveals that the former group makes more frequent use of OA publishing compared to the latter group, which suggests that only those with strong motivations will work to overcome the obstacles in their social and physical environments. The individual differences within the discipline suggest that bio-scientists are unlikely to respond to OA policies in the same way and, thus, we question the appropriateness of one-size-fits-all OA policies. We show that psychological analyses of scientists’ behaviour can inform the design of more targeted policies and organisational interventions aimed at steering a transition to the OA model of academic publishing.