Proceedings of the Annual Meeting of the Cognitive Science Society

Rock, Paper, Scissors (RPS) is a competitive game. There arethree actions: rock, paper, and scissors. The game’s rules aresimple: scissors beats paper, rock beats scissors and paper beatsrock (all signs stalemate against themselves). Over multiplegames with the same opponent, optimal play according to aNash Equilibrium requires subjects to play with genuinerandomness. To examine randomness judgments in the contextof competition, we tested subjects with identical sequences intwo conditions: one produced from a dice roll, one fromsomeone playing rock, paper, scissors. We compared thesefindings to models of subjective randomness from Falk andKonold (1997) and from Griffiths and Tenenbaum (2001),which explain assessments of randomness as a function ofalgorithmic complexity and statistical inference, respectively.In both conditions the models fail to adequately describesubjective randomness judgements of ternary outcomes. Wealso observe that context influences perceptions of randomnesssuch that some isomorphic sequences produced fromintentional play are perceived as less random than dice rolls.We discuss this finding in terms of the relation betweenpatterns and opponent modeling.