The shaping power of market prices and individual choices on preferences. An experimental investigation

We repeatedly elicited individuals' Willingness to Accept (WTA) evaluations for an auctioned bad in an experimental setting in which truthful revelation is the (weakly) dominant strategy. We investigate whether the observation of supposedly irrelevant signals (the market price, the asks at either the bottom or the top of the distribution of asks) affect the elicited values. Our experimental sample was made up of 162 subjects partitioned in 18 independent markets characterized by different informational conditions. Our analysis provide two main findings. First, individuals’ WTA evaluations are remarkably driven by a strong although unexpected tendency to conform to the asks either at the bottom or the top of the distribution by a factor of 44-66\%. Second, although a clear tendency to adapt one's own ask to the market price (Shaping effect) emerges when no other information is being provided, the provision of information about the actual behavior of well identified (groups of) individuals more than halves its magnitude, suggesting that this effect may also qualify as a peculiar case of conformity. We conjecture that in the context at hand conformity emerges as an adaptive response to a problem of preferences imprecision. Our results are identified by means of a methodology not yet employed in the field, which helps in distinguishing between the dynamic and the asymptotic features of preference formation in the presence of either adaptive or rational expectations. The overall evidence suggests a decisive role for market interactions in the definition of preferences.