Behaviour is the function of person and environment
It is known in social psychology that behaviour is a function of person and environment. This means that behaviour is influenced by personal and situation factors. What is often forgotten is that environmental factors have a strong effect on behaviour. We can see how the environment effects behaviour at work, neighbourhoods on social behaviour and every day life, and the effects of public places and institutions on behaviour between people.
When designing for behavioural change, try to consider the effect that the environment can have on behaviour of individuals and groups. The interaction between environment and person is bigger than you think.