  Theory purports that animal foraging choices evolve to maximize returns, such
as net energy intake. Empirical research in both human and nonhuman animals
reveals that individuals often attend to the foraging choices of their
competitors while making their own foraging choices. Due to the complications
of gathering field data or constructing experiments, however, broad facts
relating theoretically optimal and empirically realized foraging choices are
only now emerging. Here, we analyze foraging choices of a cohort of
professional day traders who must choose between trading the same stock
multiple times in a row---patch exploitation---or switching to a different
stock---patch exploration---with potentially higher returns. We measure the
difference between a trader's resource intake and the competitors' expected
intake within a short period of time---a difference we call short-term
comparative returns. We find that traders' choices can be explained by foraging
heuristics that maximize their daily short-term comparative returns. However,
we find no one-best relationship between different trading choices and net
income intake. This suggests that traders' choices can be short-term win
oriented and, paradoxically, maybe maladaptive for absolute market returns.

Populations and Evolution;Physics and Society