Where a friend solicits an office and fails, while another succeeds, may illustrate the potential mixing of pure chance with elements of skill. The successful case may reflect a comparative skill edge. Important laboratory experiments control for any skill effects by examining the effect of reversing the first movers' intended outcome with “pure” probabilityProbability 0.25. Second movers respond at rates approximately the same as when offers to cooperate are known to be intended, giving first movers the benefit of the doubt concerning intentionsIntention known to be unreliable in 25 percent of the cases. It seems that these responders to cooperative offers may be somewhat concerned not to discourage favorable social behavior if it was intended.