We offer an evolutionary model of the emergence of concepts of salience through similarity-based learning. When an individual faces a new decision problem, she chooses an action that she perceives as similar to actions that, when chosen in similar previous problems, led to favourable outcomes. If some similarities are more reliably perceived than others, this process will favour the emergence of conventions that are defined in terms of reliably-perceived similarities. We present experimental evidence of such learning in recurrent play of similar but not identical pure coordination games.