Proceedings of the Annual Meeting of the Cognitive Science Society

Prevalence-induced concept change describes a cognitivemechanism by which someone’s definition of a concept shiftsas the prevalence of exemplars of that concept changes. Forinstance, in a task where people have to judge whether thecolour of an ambiguously-coloured dot is blue or purple, if thefrequency of objectively blue dots in the environmentdecreases, people expand their concept of blueness and judgemore dots to be blue than they did initially. In a series ofexperiments, Levari et al. (2018) demonstrated that thisphenomenon extends to higher-order decision-making, suchas ethical judgments as well. What these findings suggest isthat conceptual spaces (whether it’s about colours or ethicalstatements) in humans are not fixed, but are sensitive tochange. While Levari et al. (2018) established thisphenomenon in young adults, it is unclear how it affects olderadults: do they outsource control and become moresusceptible to concept change or are they rigid enough in theirbeliefs to be resistant to it? In the current study, we explorehow prevalence-induced concept change affects older adults’lower-level, perceptual, and higher- order, ethical,decision-making. We find that older adults are less sensitiveto prevalence-induced concept change than younger adultsacross both domains. A computational model reveals thatthese differences might in part be explained by older adults’tendency to perseverate (repeat responses). Our resultssuggest that older adults’ concept space may be less flexiblethan younger adults’ when faced with a changing world.