Bidding challenges learning theories; even with the same bid, experiences vary stochastically: the
same choice can result in either a gain or a loss. In such an environment the question arises how
the nearly universally documented phenomenon of loss aversion affects the adaptive dynamics. We
analyse the impact of loss aversion in a simple auction using the experienced-weighted attraction
model of learning. Our experimental results suggest that individual learning dynamics are highly
heterogeneous and affected by loss aversion to different degrees. Apart from that, the experiment
shows that loss aversion is not specific to rare decision making.