Fig 4. The relation of reinforcement statistics to payoff and cost.

The graph shows a representative reinforcement distribution over the magnitude r of all received reinforcements. The parts of the distribution that indicate negative reinforcements (costs) are colored red, while the parts that indicate positive reinforcements (payoffs) are colored green. The mean q and the mean spread s are indicated above the distribution, the mean cost −n and the mean payoff p are indicated below the distribution.