*Background*: Recent studies show that secure coding is about not only technical requirements but also developers’ behaviour. *Objective*: To understand the influence of socio-technical contexts on how developers attend to and engage with security in code, software engineering researchers collaborated with social psychologists on a psychologically-informed study. *Method*: In a preregistered, between-group, controlled experiment, 124 developers from multiple freelance communities, were primed toward one of three identities, following which they completed code review tasks with open-ended responses. Qualitative analysis of the rich data focused on the attitudes and reasoning that shaped their identification of security issues within code. *Results*: Overall, attention to code security was intermittent and heterogeneous in focus. Although social identity priming did not significantly change the code review, qualitative analysis revealed that developers varied in how they noticed issues in code, how they addressed them, and how they justified their choices. *Conclusion*: We found that many developers do think about security – but differently from one another. Hence, effective interventions to promote secure coding must be appropriate to the individual development context.