Humans routinely form groups to achieve goals that no individual can accomplish alone. I will describe three paradigms for studying how effective coordination in a group can emerge even when the members cannot explicitly communicate with one another. In “Group Binary Search,” a computer generates a mystery random number between 1 and 100, and every member of a 2-17 person group guesses a number. On every round, the computer compares the sum of the guesses to its mystery number and gives exact feedback to every group member about how much the group’s sum was off by. In “Battles of the Exes” two players move their avatars to low and high payoffs, but if they both pick the same target then neither player receives any payoff. In “Find the Unicorn” two players overturn tiles to determine whether a unicorn is present or absent, earning points if they are correct but having points deducted when they both overturn the same tile. In all three paradigms, we find that good group coordination involves not the members all doing the same thing at the same time, but rather a division of labor. successful division of labor is facilitated by players assuming specialized roles, with players becoming consistent in their own behavior, and becoming differentiated from the other players. The computational models that fit human behavior the best and perform the best have mechanisms to strategically differentiate a player’s behavior from others – to fit well with what the player thinks the other players are trying to do.


Robert Goldstone is Distinguished Professor in the Psychological and Brain Sciences department and Cognitive Science program at Indiana University. His research interests include concept learning and representation, perceptual learning, educational applications of cognitive science, decision making, collective behavior, and computational modeling of human cognition. He won the 2000 APA Distinguished Scientific Award for Early Career Contribution to Psychology, and a 2004 Troland research award from the National Academy of Sciences. He was the executive editor of Cognitive Science from 2001-2005, Director of the Indiana University Cognitive Science Program from 2006-2011, and is current executive editor of Current Directions in Psychological Science. He has been elected as a fellow of the Society of Experimental Psychologists, the Cognitive Science Society, and the American Academy of Arts and Sciences.