The security is created, by and for the humans. Security decisions are heavily influenced by human behaviours that decide how much security is adequate, and what is the good or bad security. More often than not, the needs of the security protection arise from risk perception rather than actual risks. Entire physical security program relies heavily on the deterrence factor and other psychological elements to improve the sense of security.

Most, if not all, of the security threat sources are from humans. Meanwhile humans are also the weakest links in security defence. Therefore, security professionals must understand human behaviour and its impact on security decisions when designing effective programs. No security program will succeed without understanding human behaviour.

Human behaviour is a science, can be observed, explained and predicted; Incorporated human behaviour into security decisions is an art, where personal experience, judgement and skills are needed. Hence, behavioural security is both science and art.