A hierarchical modular architecture for embodied cognition

Cognition can appear complex owing to the fact that the brain is capable of an enormous repertoire of behaviors. However, this complexity can be greatly reduced when constraints of time and space are taken into account. The brain is constrained by the body to limit its goal-directed behaviors to just a few independent tasks over the scale of 1-2 min, and can pursue only a very small number of independent agendas. These limitations have been characterized from a number of different vantage points such as attention, working memory and dual task performance. It may be possible that the disparate perspectives of all these methodologies can be unified if behaviors can be seen as modular and hierarchically organized. From this vantage point, cognition can be seen as having a central problem of scheduling behaviors to achieve short-term goals. Thus dual-task paradigms can be seen as studying the concurrent management of simultaneous, competing agendas. Attention can be seen as focusing on the decision as to whether to interrupt the current agenda or persevere. Working memory can be seen as the bookkeeping necessary to manage the state of the current active agenda items.