Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
The Condorcet jury model with costless but informative signals about the true state of the world predicts that the efficiency of group decision-making increases unambiguously with the group size. However, if signal acquisition is made an endogenous and costly decision, then rational voters have disincentives to purchase information as the group size becomes larger. We investigate the extent to which human subjects recognize this trade-off between better information aggregation and greater incentives to free-ride in a laboratory experiment where we vary the group size, the cost of information acquisition and the precision of signals. We find that the theory predicts well in the case of precise signals. However, when signals are imprecise, free-riding incentives appear to be much weaker as there is a pronounced tendency for subjects to over-acquire information relative to equilibrium predictions. We rationalize the latter finding using a quantal response equilibrium that allows for risk aversion.