  According to Brooks, his Creatures have no need for representations. Implementing an idea from ecological psychology, Brooks says that the activity layers in his robots connect “perception to action directly” (1991b, 144). A robot designed in this way need not represent the world because it is able to “use the world as its own model” (1991b, 139). The robot’s behavior evolves through a continuous loop: the body moves, which changes the stimulation its sensors receive, which directly causes new movement, and so on. Because nothing stands “in between” the sensory signals and the robot’s behavior, there is no need for something that plays the standard intermediating role of a representational state. The robot does not require, for instance, a model of its environment in order to navigate through hallways. The move-sense loop does its job without one.