Hebb O Donald 1945

Hebb, D.O. (1949). Organization of Behavior: A Neuropsychological

Theory (New York: John Wiley and Sons).

Mind

If one is to be consistent, there is no room here for a mysterious agent that is defined as not physical and yet has physical effects (especially since many of the entities of physics are known only through their effects). “Mind” can only be regarded, for scientific purposes, as the activity of the brain…(introduction pp. xiii and xiv).

Thought

The central problem with which we must find a way to deal can be put in two different ways.  Psychologically, it is the problem of thought: some sort of process that is not fully controlled by environmental stimulation and yet cooperates closely with that stimulation. From another point of view, physiologically, the problem is that of the transmission of excitation from sensory to motor cortex. This statement may not be as much oversimplified as it seems, especially when one recognized that the “transmission” may be a very complex process indeed, with a considerable time lag between sensory stimulation and the final motor response. The failure of psychology to handle thought adequately (or the failure of neurophysiology to tell us how to conceive of cortical transmission) has been the essential weakness of modern psychological theory and the reason for a persistent difficulties in dealing with a wide range of experimental and clinical data, as the following chapters will try to show, from the data of perception and learning to those of hunger, sleep, an neurosis. In mammals even as low as the rat it has turned out to be impossible to describe behavior as an interaction directly between sensory and motor processes. Something like thinking, that is, intervenes. “Thought” undoubtedly has the connotation of a human degree of complexity in cerebral function and may mean too much to be applied to lower animals. But even in the rat there is evidence that behavior is not completely controlled by immediate sensory events: there are central processes operating also.  

What is the nature of such relatively autonomous activities in the cerebrum? Not even tentative answer is available. We know a good deal about the afferent pathways to the cortex, about the efferent pathways from it, and about many structures linking the two. But the links are complex, and we know practically nothing about what goes on between the arrival of an excitation at a sensory projection area and its later departure from the motor area of the cortex.  (introduction p. xvi)