Why scarcity can both increase and decrease prosocial behaviour: A review and theoretical framework for the complex relationship between scarcity and prosociality.

In recent years, scholars from different fields have studied the effects of scarcity on social behaviour, producing mixed findings. This review synthesizes the most recent literature on the topic and proposes a framework to organize the evidence. According to this framework, scarcity produces an attentional shift towards the scarce resource and a cognitive load that triggers heuristic thinking; this affects social behaviour in various ways, depending on individual and contextual factors, which can be transient (e.g., emotional states or social expectations), or enduring (e.g., personality or social environment). We then apply this framework to explain when and how scarcity influences parochialism. We conclude with a caution against the uncritical use of scarcity salience as a tool for social behavioural change.