Focusing on responder behavior, we report panel data findings from both low and high stakes ultimatum bargaining games. Whereas Slonim and Roth (1998) find that offers are rejected fairly equally across rounds in both low and high stakes games, we find that learning does take place, but only when there is sufficient money on the table. The disparate results can be reconciled when one considers the added power that our experimental design provides-detecting subtle temporal differences in responder behavior requires a data generation process that induces a significant number of proportionally low offers.