There are a number of plausible ways in which a given amount of available time can be allocated
to a set of to-be-learned items. For instance, one might spend most time on those items that are
judged to be the most difficult or furthest away from a learned state (Dunlosky and Hertzog, 1998).
Alternatively, time may be allocated disproportionately to items of intermediate difficulty, with
more challenging items receiving attention only when time pressure is not binding (Metcalfe, 2002).
In these and other related theories, the idea of optimality has often been invoked, but without the
development of a rigorous model of optimizing behavior. This is the gap in the literature that we
seek to fill.