We propose a model of cognitive process allowing virtual agents to exhibit anticipatory abilities. With user experiments, we show that this mecha- nism brings about an improvement in the efficiency of the behavior generated, and check that external observers are able to perceive it. We also confirm that this improvement in efficiency leads, up to a point, to an improvement in be- lievability as judged by human observers. Beyond this level of efficiency, be- lievability reaches a plateau.