The idea of the was introduced by Herbert A. Simon and developed in economics by Richard Cyert and James March in their 1963 book "A Behavioral Theory of the Firm". The aspiration level is the payoff that the agent aspires to: if the agent achieves at least this level it is satisfied, and if it does not achieve it, the agent is not satisfied. Let us define the aspiration level ' and assume that . Clearly, whilst it is possible that someone can aspire to something that is better than the optimum, it is in a sense irrational to do so. So, we require the aspiration level to be at or below the optimum payoff.