Proceedings of the Annual Meeting of the Cognitive Science Society

Humans perceive facial expressions categorically, though physical features of emotions vary continuously. How do cat-egorical representations of facial expressions emerge or update? We explored how supervised and unsupervised learninginfluence emotion category boundaries. 91 children (6-8-years-old) and 105 adults categorized emotions varying along aneutral-angry continuum. Participants completed a supervised learning phase, which explicitly taught an emotion cate-gory boundary. Then, participants completed an unsupervised learning phase. Without feedback, participants categorizedexpressions sampled from statistical distributions that matched or did not match the distribution categorized during su-pervised learning. Participants learned the boundary via supervised learning, but responses rapidly shifted followingthe statistical distribution via unsupervised learning. Thus, participants quickly updated emotion categories, indicatingboundaries are highly context-sensitive. Such flexibility allows individuals to adjust across situations and organize re-sponses based on extant, versus explicitly taught, socio-emotional cues. Follow-up research explores how participantsadjust category boundaries for multiple individuals varying in expressivity.