The psychosemantics of free riding: dissecting the architecture of a moral concept.

For collective action to evolve and be maintained by selection, the mind must be equipped with mechanisms designed to identify free riders--individuals who do not contribute to a collective project but still benefit from it. Once identified, free riders must be either punished or excluded from future collective actions. But what criteria does the mind use to categorize someone as a free rider? An evolutionary analysis suggests that failure to contribute is not sufficient.