Insights from the behavioural sciences and organisational psychology have a fundamental role to play in helping us to understand how to encourage better cyber security behaviours. This new RISCS Fellowship theme investigates how people behave and make decisions, both individually and in groups, and across different parts of the cyber security ecosystem. In particular, it will work with an innovative story stem methodology to sensitively explore our understanding of cognition and behaviour around security adoption decision-making. This research theme will help to guide the RISCS community towards new insights into the psychology of cyber security, and the behaviours upon which a positive cyber security culture is built.