Year: 1954
Type: book
Abstract: The book is not a treatise on all cerebral mechanisms but an attempt to solve a specific problem : the origin of the nervous system's unique ability to produce adaptive behaviour.The work has as basis the fact that the nervous system behaves adaptively and the hypothesis that it is essentially mechanistic ; it proceeds on the assumption that these two data are not irre- concilable.It attempts to deduce from the observed facts what sort of a mechanism it must be that behaves so differently from any machine made so far.Many other workers have proposed theories on the subject, but they have usually left open the question whether some different theory might not fit the facts equally well.I have attempted to deduce what is necessary, what properties the nervous system must have if it is to behave at once mechanistically and adaptively.Proceeding in this way I have deduced that any system which shows adaptation must (1) contain many variables that behave as step-functions, (2) contain many that behave as part-functions, and (3) be assembled largely at random, so that its details are determined not individually but statistically.The last require- ment may seem surprising : man-made machines are usually built to an exact specification, so we might expect a machine assembled at random to be wholly chaotic.But it appears that this is not so.Such a system has a fundamental tendency, shown most clearly when its variables are numerous, to so arrange its internal pattern of action that, in relation to its environment, it becomes stable.If the system were inert this would mean little ; but in a system as active and complex as the brain, it implies that the system will be self-preserving through active and complex behaviour.The work may also be regarded as amplifying the view that the nervous system is not only sensitive but ' delicate ' : that its encounters with the environment mark it readily, extensively, and permanently, with traces distributed according to the 4 accidents ' of the encounter.Such a distribution might be expected to produce a merely chaotic alteration in the nervous system's behaviour, but this is not so : as the encounters multiply there is a fundamental tendency for the system's adaptation to improve, for the traces tend to such a distribution as will make its behaviour adaptive in the subsequent encounters.* The summary is too brief to be accurate ; the full text should be con- sulted for the necessary qualifications.
Source: Wiley eBooks
Author: William Ross. Ashby
Language: English
Topic: Memory and Neural Mechanisms
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W4235796286