Chemero makes a curious statement about Gibson in a recent paper:
The claim that the cognitive system is not in the head at all, that cognition is to be explained entirely in terms of the interactions of whole animals and their environments, may seem like an automatic nonstarter and an idea so crazy that no one would have held it. That is not so. Skinnerian behaviorists still make claims like this (Hineline 2006), and the later work of Gibson (1979) can be interpreted as making claims like this. In both cases, the claim is that all of the explanatory work can be done by carefully studying the ways active animals interact with the environment. In the Skinnerian case, one focuses on the subtle ways that animal behavior is shaped by environmental outcomes, and claims that reinforcement learning can account for the whole gamut of behavior.In the Gibsonian case, one focuses on the breathtaking amount of information available to a perceiver, especially one that is moving, and claims that this information is sufficient for perception of the environment without the addition of information stored in the brain. Note that neither Gibson nor Skinnerians claim that the brain is not importantly involved in cognition; rather they claim that psychologists can do all their explanatory work without referring to the brain.
First claim: ecological information in the environment is sufficient for perception of the environment.
This sounds weirdly put to me. I think a better way of stating Gibson’s claim would this: the discrimination of ecological information from the environment is sufficient for the control of action in that environment. The point is not that “cognition ain’t going on in the head”, but rather, that the brain doesn’t need to build an internal model of the environment in order to successfully navigate it. If we define cognition as the “coordination of motor control”, then it seems metaphysically plausible that this is taking place inside the head, without violating the spirit of Gibsonian psychology.
Second claim: Gibson thought that psychology can be complete without referring to the brain.
I’d like to see some solid textual evidence supporting this interpretation. I do not recall Gibson ever saying such a ridiculous thing. If we want to give a complete account of how information is discriminated then we are going to have start talking about the brain. Gibson never talked about the brain only because so much more conceptual work needed to be done. It is only after we have laid down the basic foundation of affordance theory that we should investigate the brain, otherwise we might be prone to improperly determine the computational task. Gibson was against cognitivist theories only because he thought they were positing unnecessary steps in the computational process. For example, we don’t need to compute information about depth from a 2D picture because the information specific for depth is already available in the ambient optic array.
However, if we redefine cognitive computation in terms of controlling action-perception cycles, then there is a real sense in which the brain is computing information. Rather than doing the computation in terms of discrete mental representations and internal, lingua-form models (that get experienced as a rich picture of the external world), the computation of information is done in terms of sensorimotor connectivity. On Edward Reed’s selectionist account and Robbins’ subtractionist account, Gibson’s affordance theory actually makes empirical predictions about how variable neural activity is coordinated so as to produce functionally specific responses to changing environmental demands. Gibsonian information theory actually predicts that the brain will seek out invariances in the environment so as to “select” the most functionally advantageous course of action from out of the “virtual phasespace” of the neural population dynamics. This approach turns out to endorse a theoretically deep model of decision-making and attention-control at the prereflective level. Moreover, such a selectionist account is self-consciously compatible with evolutionary biology and developmental systems theory insofar as the emphasis is on plasticity and adaptation.
So, far from being a psychological theory that completes itself without referencing the brain, Gibsonian theory actually provides a radical new approach to understanding small and large scale brain dynamics. Once we have done the hard theoretical work of determining what kind of affordance information is available in the environment, we must then look into the brain and determine how the discrimination of such information allows for the coordination of neural dynamics in such a way as to bring about functionally specific, adaptive behavior in response to changing environmental demands.