This paper compares stimulus response (SR) and belief-based learning (BBL) using data from experiments with sender-receiver games. The environment, extensive form games played in a population setting, is novel in the empirical literature on learning in games. Both the SR and BBL models fit the data reasonably well in games where the preferences of senders and receivers are perfectly aligned and where the population history of the senders is known. The test results accept SR and reject BBL in games without population history and in all but one of the games where senders and receivers have different preferences over equilibria. Estimation is challenging since the likelihood function is not globally concave and the data become uninformative about learning once equilibrium is achieved.
