Piero Scaruffi

These are excerpts and elaborations from my book "The Nature of Consciousness"

The Primacy Of Connections The US psychologist Edward Thorndike, a student of William James had already explained how Skinner's reinforcement occurs. Thorndike had been the first psychologist to propose that animals learn based on the outcome of their actions (the "law of effect") and Skinner simply generalized his ideas. The “law of effect” stemmed from the observation that animals do not learn from the success of other animals; nor do they learn if guided to the correct solution. They learn based on how their own actions succeed or fail. The “law of effect” states that the probability that a stimulus will cause a given response is proportional to the satisfaction that the response has produced in the past, and inversely proportional to the dissatisfaction. This principle was consistent with both natural selection and behaviorist conditioning/reinforcement.  It complied with Darwinism because it assumed that responses were initially random and later “selected” by success or failure. It improved Pavlovian conditioning because it explained how new patterns of behavior could emerge. Thorndike modeled the mind as a network of connections among its components. Learning occurs when elements are connected. A habit is nothing more than a chain of “stimulus-response” pairs. Behavior is due to the association of stimuli with responses that is generated through those connections. This model was also consistent with gestalt holism because in a vast network of connections the relative importance of an individual connection is negligible. Connectionism can be viewed at various levels of the organization of the mind.  At the lowest level, it deals with the neural structure of the brain. The brain is reduced to a network of interacting neurons. Each neuron is a fairly simple structure, whose main function is simply to transmit impulses to other neurons. When anything happens to a neuron, it is likely to affect thousands of other neurons because its effects can propagate very quickly from one neuron to the other. From the outside, the only thing that matters is the response of the brain to a certain stimulus. But that response is the result of thousands of messages transmitted from neuron to neuron according to the available connections.  A given response to a given stimulus occurs because the connections propagate that stimulus from the first layer of neurons to the rest of the connected neurons until eventually the response is generated by the last layers of neurons. As long as the connections are stable, a given stimulus will always generate the same response. When a connection changes, a different response may be produced. Connections change, in particular, when the brain “learns” something new. The brain "learns" what response is more appropriate to a given stimulus by adjusting the connections so that next time the stimulus will produce the desired response. The functioning of the brain can be summarized as a continuous refining of the connections between neurons. Each connection can be strengthened or weakened by the messages that travel through it. In 1949 the Canadian physiologist Donald Hebb realized that strengthening and weakening of connections depend on how often they are used. If a connection is never used, it is likely to decay, just like any muscle that is not exercised. If it is used very often, it is likely to get reinforced. A Darwinian concept came to play a key role in the organization of the brain: competitive behavior. Connections "compete" to survive.  At a higher level, a connectionist organization can be found in the way our mind organizes concepts. Concepts are not independent of each other: a concept is very much defined by the other concepts it relates to. The best definition of a concept is probably in terms of other concepts and the way it relates to them. Concepts also rely on an associative network. Therefore, William James’ four maxims also apply to concepts. Ultimately, the connectionist model explained the functioning of the brain by employing the same paradigm that Darwin had used to explain the evolution of life: design without a designer.   Back to the beginning of the chapter "Inside The Brain" | Back to the index of all chapters