Economists and philosophers disagree about the concept of choice used in economics. Some behavioural economists argue that economic models of choice will improve as they become more and more psychologically realistic. Don Ross argues that this argument fails because its hidden assumption – that the economic concept of choice is the same as the psychological counterpart – is false. Ross conjectures that the economic concept of choice concerns a population-scale pattern of behavioural changes in response to incentives. We conduct a survey experiment to test two predictions that Ross’s conjecture generates. The statistical analysis of our data confirms our predictions, although with some qualifications. In interpreting our results, we distinguish two versions of commonsensible realism, strong and weak, and propose the weak one as a plausible explanation of our results. Weak commonsensible realism also produces further testable hypotheses. Some methodological implications of our study are discussed.