Detailed neurological models of the brain lie at the other end of the machine consciousness spectrum. Rodney Cotterill, a neuroscientist at the Technical University of Denmark near Copenhagen, analyses brain scans from living brains, both human and animal, to identify the neurochemical interactions in the brain that he believes are essential for consciousness. On a computer, he builds simulations of these interactions to model how consciousness might emerge.
His idea requires us to understand the way in which an organism probes its environment and acts on it – the “action plans” which he says are the basis of conscious thought. Cotterill points to specific structures in the brain that appear to have evolved to help the organism interact with its environment. He has produced a full map of the brain that highlights the role that many constituent parts play in generating action plans.
Going further in the direction of neurophysiology, Pentti Haikonen, a principal scientist at Nokia in Helsinki, has recognised that to model the activity in brain modules the corresponding artificial modules need to contain many neurons and be highly interactive.
Haikonen’s work supports my own idea, which is based on an overwhelming body of neurophysiological evidence suggesting there are cells in the brain that compesate for motion, such as eye movement, in oder to represent objects as they are in the real world. This allows us to get a sensation of the real world despite the constantly changing stream of sensory inputs, such as smell, vision and so on, that feeds our brains. To me, this evidence implies that our brains contain some sort of persistent representation of the outside world, encoded in the electrochemical impulses in their neurons.
And so my own design for a conscious machine starts by assuming that there is a neural “depiction” in the brain that exactly matches every scrap of our inner sensations. In order to form consciousness, these depictions have to have at least five major qualities. First, there is a sense of place. Depiction makes me feel that I am in the middle of an “out there” world. Second, I am aware of the past. I know that depictions of the past can occur simultaneouely with depictions of the present. Third, I can focus. I am conscious only of that to which I attend. Fourth, I can predict and plan. Depictions can occur which lay in my mind alternative scenarios of the future – how the world might respond to my actions. Finally, I can feel emotions. Emotions guide me in my choice of which plans are good for me and which are not.
I believe that these five major axioms can be accomplished by what scientists have called artificial neural networks; these are simple approximations to the way neurons in the brain actually work. We have built machines that incorporate the first four axioms. The fifth axiom is still the subject of intensive work.