  We study a spatial, one-shot prisoner's dilemma (PD) model in which selection
operates on both an organism's behavioral strategy (cooperate or defect) and
its choice of when to implement that strategy across a set of discrete time
slots. Cooperators evolve to fixation regularly in the model when we add time
slots to lattices and small-world networks, and their portion of the population
grows, albeit slowly, when organisms interact in a scale-free network. This
selection for cooperators occurs across a wide variety of time slots and it
does so even when a crucial condition for the evolution of cooperation on
graphs is violated--namely, when the ratio of benefits to costs in the PD does
not exceed the number of spatially-adjacent organisms.
