In the near future, Paul Cisek’s latest paper will appear and the abstract on the pre-publication is:
How does the brain decide between actions? Is it through comparisons of abstract representations of outcomes or through a competition in a sensorimotor map defining the actions themselves? Here, I review strengths and limitations of both of these proposals, and suggest that decisions emerge through a distributed consensus across many levels of representation.
This peaked my interest in Cisek’s work. Here is how he introduces his research on his website:
I am interested in how the brain controls behavior. Many scientists approach this very large question by starting with perception and asking how the brain builds an internal representation of the world, and how it then uses this representation to guide action. In contrast, I study behavior by starting with a concrete task such as a voluntary movement and asking what parameters of the task the brain must specify and control, and what information from the environment it may employ toward that specification. The goal here is an understanding of brain mechanisms for mediating interaction with the world, not necessarily of mechanisms for representing the world. A research program based on such an approach begins with questions concerning motor control and gradually works its way toward the perceptual systems which guide that control. One could say I’m going backwards through the brain…
This is not the usual approach. Although, he is not the first person to say it would be better to start with action rather than the senses, he is pursuing the idea consistently in his research.
A couple of years ago his group published a review paper (citation below). This is its abstract:
The neural bases of behavior are often discussed in terms of perceptual, cognitive, and motor stages, defined within an information processing framework that was originally inspired by models of human abstract problem solving. Here, we review a growing body of neuro-physiological data that is difficult to reconcile with this influential theoretical perspective. As an alternative foundation for interpreting neural data, we consider frameworks borrowed from ethology, which emphasize the kinds of real-time interactive behaviors that animals have engaged in for millions of years. In particular, we discuss an ethologically-inspired view of interactive behavior as simultaneous processes that specify potential motor actions and select between them. We review how recent neuro-physiological data from diverse cortical and subcortical regions appear more compatible with this parallel view than with the classical view of serial information processing stages.
He starts with animal behaviour (ethology) rather than human cognition because:
Contrary to popular belief, brain evolution has been remarkably conservative. Since the development of the telencephalon, the basic outline of the vertebrate nervous system has been strongly conserved . The conservative nature of brain evolution motivates us to think about large-scale theories of neural organization from the perspective of the kinds of behaviors that animals engaged in many millions of years ago, when that neural organization was being laid down. … their nervous systems have been preoccupied by almost constant interaction with a complex and ever changing environment, which continuously offers a potentially bewildering variety of opportunities and demands for action.
He describes his theory, Affordance Competition Hypothesis , in which ‘action selection’ and ‘action specification’ are simultaneous. He concludes:
Brains evolved for sensorimotor control and retained much of that architecture—even the neocortex is still part of that old circuit.
Natural interactive behavior requires sensorimotor control and selection systems to operate continuously and in parallel.
Distinctions between perceptual, cognitive, and motor processes, although descriptively useful, might not reflect the natural categories of the brain’s functional organization.
Decisions appear to be made through a distributed consensus that emerges in competitive populations.
Neurophysiological data may be more readily interpreted from the perspective of interactive behavior than from the perspective of serial information processing.
This has bearing on the interpretation of the Libet and similar experiments. If there is not a serial sensory-cogitive-motor pattern that is separated in time and location, it is very unlikely that conscious intention precedes action, possibly it is impossible.
Paul Cisek, & John Kalaska (2010). Neural Mechanisms for Interacting with a World Full of Action Choices Annu. Rev. Psychol. DOI: 10.1146/annurev.neuro.051508.135409