This work uses four different experiments to explore some of the factors that can help explain and predict cooperative/prosocial behaviour. The first two experiments use the social dilemma of a two–player public goods game to explore the role of observability by others, along with, the role of beliefs/norms. Both find robust evidence in support of guilt aversion where an individual experiences a disutility simply from failing to meet the expectations of others (or their belief of what these expectations are), this being possible even when there is no observability by others. Both also find evidence for some people behaving in a “shame averse” way, this being where individuals experience a disutility from their behaviour being observed by others, in combination with, (as with guilt aversion) this behaviour failing to meet (their belief about) the expectations of others. The other two experiments look at a more specific situation, that of paying a “queue jumping bribe”. It is found that both “citizens” and “officials” choose/accept a bribe less when there is a negative time externality attached to it (a third party being “pushed down the queue” and having to wait longer for service delivery). Citizens are also less likely to choose the bribe when a more costly “fast track fee” is available.