"We have suggested that thought consists in modeling the environment and using the method to predict the future state of the world....By introducing the idea of a payoff function, we can control the motivational input to the organism, and so increase the likelihood of having its insights manifested in action. We then proposed an hypothesis relating S-R behavior and insightful behavior, and described some scraps of evidence in its support. Finally we pointed to the need for an independent measure of "problem complexity" before we could get to the critical problem of the relation between the motivational structure of the person and the characteristics of the insight he reveals.".