A note on making humans randomize

•We study behavior in a two-person 4×4 pure coordination game.•We want that subjects select all options with the same probability.•The display of actions must be free from salient properties.•We identify two sets of action labels that produce a uniform choice distribution.•Our design can be used to compare risk with strategic uncertainty.

This note presents results from an experiment studying a two-person 4×4 pure coordination game. We explore different strategy labels in an attempt to implement the mixed-strategy equilibrium that selects all four strategies with equal probability. Such strategy labels must be free from salient properties that might be used by participants to coordinate. Testing 23 different sets of strategy labels, we identify two sets that produce a distribution of subjects’ choices which approximate the uniform distribution quite well. Our results are relevant for studies intending to compare the behavior of subjects who play against a random mechanism with that of participants who play against human counterparts.