The effect of fast and slow decision-making on equity-efficiency tradeoffs and moral repugnance.

Fast-and-slow models of decision-making are commonly invoked to explain economic behaviour. However, past research has focused on human cooperation and generosity and thus largely overlooked situations where there are sharp conflicts between efficiency and equality, or between efficiency and more intuitive moral values (repugnance). Here, we contribute to fill this gap in the literature. We conducted a preregistered experiment ( = 1500 recruited from Prolific) to assess the effects of fast, intuitive decisions, under time pressure versus slow, deliberate decisions, under time delay, on (i) people's distributional preferences and (ii) their attitudes toward repugnant transactions. The results show increased preference for equality and decreased preference for efficiency under time pressure, but no effects on moral repugnance. Exploratory analyses revealed that most of the observed treatment effects in our data were accounted for by women. Our results provide some support for theories that associate controlled cognition with concern for efficiency, and intuitive, emotional responses with inequality aversion.