Attention as an effect not a cause

• Current models of attention are based on the premise of limited sensory resources.
• We propose that attention arises as a byproduct of value-based decision making.
• Decision making requires estimating the current state of the animal and environment.
• Filter-like properties of attention arise from weighted inputs to the current state.
• The brain mechanisms involve a subcortical circuit motif that predates the neocortex.

Attention is commonly thought to be important for managing the limited resources available in sensory areas of the neocortex. Here we present an alternative view that attention arises as a byproduct of circuits centered on the basal ganglia involved in value-based decision making. The central idea is that decision making depends on properly estimating the current state of the animal and its environment and that the weighted inputs to the currently prevailing estimate give rise to the filter-like properties of attention. After outlining this new framework, we describe findings from physiological, anatomical, computational, and clinical work that support this point of view. We conclude that the brain mechanisms responsible for attention employ a conserved circuit motif that predates the emergence of the neocortex.