Studies of brain activity during perception by animals trained to discriminate
olfactory, visual, auditory, or tactile stimuli have led to a view of perception
as goal-directed action that is organized by large scale neural interactions
in the limbic system. Such action is intentional, in that it forms within
a framework of space and time that has been constructed from recent and remote
experiences of action and its sequellae, and it is realized by directed action
into the world, intended to shape the self in accordance with what is there,
leading to knowledge of the world through such action. The motor "commands"
that issue through the septum and amygdala are accompanied by reafferent "corollary
discharges" sent by the limbic system to all of the sensory cortices, which
constitute attention by shaping the dynamic sensitivities of the cortices in
respect to the anticipated changes in sensory inflow that will follow the intended
actions. Thus the sensory systems are already primed to respond in selective
ways to the stimuli that are being sought through listening, looking, sniffing,
etc. Closure of the action-perception cycle takes place following the de-stabilization
of the sensory cortices, their construction by nonlinear dynamic interactions
of spatial patterns of activity, the convergence of these patterns into the
limbic system, whence issued the request for input, and finally the updating
of the limbic activity.
In historical perspective the ancestor of this dynamic view of brain function was Thomas Aquinas, who conceived the process of intentionality as the "stretching forth" by the brain through its body into the environment, and coming to know the environment through re-shaping itself, what we now call learning through the plasticity of the brain (Freeman, 1995). Independently a similar conception of brain function was put forth by the pragmatists, most clearly by James, and by Dewey in his critique of the conditioned reflex. It was further developed by Gestalt psychologist Köhler, who studied the impact on brains of objects perceived as embedded in environmental contexts, leading to the conception of a field of force. Koffka expanded this to include interaction between fields of force in the environment and in the brain. Gibson further conceived of behavior as generated within brains in the definition of objects by means of affordances:
" ... the affordance, being invariant, is always there to be perceived. An affordance is not bestowed upon an object by a need of an observer and his act of perceiving it. The object offers what it does because it is what it is. ... It says only that the information to specify the utilities of the environment is accompanied by information to specify the observer himself. ... exteroception is accompanied by proprioception ... to perceive is to coperceive oneself."
(Gibson, 1979, p. 139).
Gibson's conception of "information" constituting "in-forming" the brain is closely analogous to the Aquinian intentional act of "stretching forth" and conforming to the environment by learning, with the difference that an affordance refers primarily to an object, whereas an intent refers to an inner brain state of an emergent goal with its unity of inner context. In Aquinian intent there is no transfer of information across the boundary of the self; all knowledge is constructed within.