We live in a world in which inconsistency is the rule rather than the exception and this is particularly true with regard to rewards and frustrations. In some cases, rewards and frustrative nonrewards appear to occur randomly for what seems to be the same behavior; in others a sequence of rewards is suddenly followed by nonrewards, or there are large rewards followed by small rewards. Sometimes we are rewarded for responding quickly, other times for responding slowly. The important common factor in these and other cases is frustration, how we learn about it and how we respond to it. Without...