Extensive research with animals and humans indicates that rewarded effort contributes to durable individual differences in industriousness. It is proposed that reinforcement for increased physical or cognitive performance, or for the toleration of aversive stimulation, conditions rewards value to the sensation of high effort and thereby reduces effort's aversiveness. The conditioning of secondary reward value to the sensation of effort provides a dynamic mechanism by which reinforced high performance generalizes across behaviors. Applications to self-control, moral development, and education are described.