“…A token earned, as opposed to one freely given, may be more highly valued. A study by Miller, DeLeon, Toole, Lieving, and Allman (), for example, found that participants who earned their own tokens were more risk averse (less likely to gamble those tokens) than participants given noncontingent (free) tokens. These findings, along with those from a similar study (Brandt, Sztykiel, & Pietras, ), suggest that the contingent delivery of tokens may enhance their value relative to those freely delivered.…”