The discount rate, γ, controls how strongly Q-learning values future rewards relative to immediate rewards. It ranges from 0 to 1: γ = 0 is myopic, while γ = 1 gives current and future rewards equal weight. This subjective preference differs from an interest rate. section 6.2.2
Financial planning example
For asset-allocation decisions, Q-learning updates the current action value using the observed reward plus γ times the best estimated value at the next wealth state. A smoker’s preference for an immediate cigarette illustrates why subjective discounting can differ from bond discounting. section 6.2.2
