Behavioural public policy should take the psychology of poverty into account.

Psychological variability is central to understanding behavioural interventions. Over the past 15 years, many behaviourally informed public policies have proven effective; however, they often yield highly heterogeneous outcomes, and the reasons for this variability remain unclear. We posit that these mixed results are due to researchers and policy makers designing interventions around behavioural strategies that perform well on average, overlooking how individuals differ in their responses. We review discoveries from the psychology of poverty to show how variations in traits such as conformism, present orientation, personal agency, and social vigilance correspond with levels of resource availability. We then demonstrate how these psychological differences systematically shape individual reactions to behavioural policy tools such as default options, self-regulation devices, information campaigns, social-belonging interventions, and social norms. Ultimately, we argue that an applied behavioural science of poverty is essential for crafting interventions that are both effective and equitable.