in contrast to the symbolic approach, distributed systems of action selection actually have no one "box" in the agent which decides the next action. at least in their idealized form, distributed systems have many modules running in parallel and determining the best action based on local expertise. in these idealized systems, overall coherence is expected to emerge somehow, possibly through careful design of the interacting components. this approach is often inspired by artificial neural networks research. in practice, there is almost always "some" centralised system determining which module is "the most active" or has the most salience. there is evidence real biological brains also have such executive decision systems which evaluate which of the competing systems deserves the most attention, or more properly, has its desired actions disinhibited.