  In the present article we emphasize the importance of modeling time in the
context of agent-based models. To this end, we present a (selective) survey of
the Cellular Automata-literature on updating and draw parallels to the issue of
agent activation in agent-based models. By means of two simple models,
Schelling's segregation model and Epstein's demographic prisoner's dilemma we
investigate the influence of choosing different regimes of agent activation.
Our experiments indicate that timing is not a critical issue for very simple
models but bears huge influence on model behavior and results as soon as the
degree of complexity increases only so slightly. After a brief review of the
way commonly used ABM simulation environments handle the issue of timing, we
draw some tentative conclusions about the importance of timing and the need for
more research towards that direction, similar to the concerted effort on
updating in cellular automata.
