Recency effectThe first element is to take the influence of time into account, and assume that propensity will decay with time. Denote the constant decaying rate by j. Then equation (2) can be developed into equation (3).A reasonable range of the parameter j is between 0 and 1. If j ¼ 1, the propensity of the last period qi,t1 will be completely ignored (forgotten), and the strengthupdating only depends on the most recently received payoffs. On the other hand, if j ¼ 0, the past propensity will not decay at all, and it in its entirety will roll over to this period. Hence, j is also known as the forgetting parameter.