Are Karl Lashley's theories of mass action and equipotentiality wrong? : LUSENET : History & Theory of Psychology : One Thread

Francis Crick wrote in The Astonishing Hypothesis that "Karl Lashley...was almost always wrong..." (p. 169). Although Crick does not specifically mention Lasley's concepts of mass action and equipotentiality Crick's sweeping dismissal of his views would appear to include them.

Are Lashley's theories generally considered to be false?

-- John Hedlin (, February 01, 2002


In "Mass function and equipotentiality: A reanalysis of Lashley's retention data," (Psychological Reports, 1970, 27, 899-902) I showed that a "finer grain" analysis of the some of the data Lashley included in his 1929 monograph, Brain mechanisms and intelligence, which established the principles of mass function and equipotentiality, did not support the principles. I suspect there is little remaining support for equipotentiality, as Lashley defined it. However, the mass function interpretation is sustainable in a number of contexts, including that of the neural mechanisms of learning and memory where Lashley first framed the principles. By way of an example, I taught neuroanatomy for many years, and as a "take-home" Final Exam, I often structured a seemingly simple behavioral event and had the students discuss the major neuroanatomical structures, pathways, etc, that might be involved. For example, a wolf and a rabbit see each other at the same time. Choose either the wolf or the rabbit and identify sequentially the neuroanatomical systems that will be activated between the moment that the wolf or rabbit detects the other until it initiates a response. (the students constructed two abstract "time lines," T1, T2, etc., one describing the behavioral sequence and one describing associated neuroanatomical involvement...acknowledging that many activities will be concurrent). My point here is that this will occur in about a second most likely, yet nearly every part of the central nervous system will have been involved (e.g., in detection, recognition, autonomic activation, initiation of a response). Even a simple rat learning task will have receptor, memorial, and effector components that will engage many areas of the nervous system (mass function?). I suspect the ultimate answer to whether Crick or Lashley was wrong will involve a synthesis of localization of function and mass function. Lashley has few research-oriented defenders or sympathizers these days. One the most effective and among the last of these may be E. Roy John. I can't locate my copy right now, but one of his articles was published in Science in 1986, and see his book, Mechanisms of memory, Academic Press, 1967.

-- Roger K. Thomas (, February 02, 2002.

I may have addressed your question too narrowly above. For a recent assessment of Lashley's theoretical contributions, as well as reprints of some of Lashley's important works, please see Jack Orbach's book, THE NEUROPSYCHOLOGICAL THEORIES OF LASHLEY AND HEBB [University Press of America, 1998 xiv, 395 pp. ISBN: 0-761-81165-6] which was discussed extensively in the on-line journal, Psycoloquy, beginning with:

I think you will find in that discussion, which involved some very competent contributors, that many of Lashley's theoretical views continue to be regarded as being useful and valuable.

-- Roger K. Thomas (, February 05, 2002.

[Posted for DB by cdg.]

Here's an off-the-top-of-my-head answer to the question. I think it is fair to say that Crick's statement is accurate. However, its damning nature has to be qualified in a number of ways. For example, Lashley was very good at showing the deficiencies in existing theory. He was also terrific at identifying important problems -- that of serial order is one of them. His serial order paper is brilliant. He was also wonderful in tossing out conjectures as to what might be going on at the level of brain to account for psychological phenomena. I like to think of him as a Popperian scientist -- proposing hypotheses and then trying to refute them. In one respect, and a very important one, however, Lashley was right. Memories are not stored in particular places. Their formation, storage, and retrieval requires the coordination of a number of different brain structures. In other words, the memory system is distributed. The research he did to show this was hardly definitive -- in fact, it's pretty weak -- but he had the right answer.

-- Darryl Bruce (dbruce@HUSKY1.STMARYS.CA), February 06, 2002.

These are very helpful responses. If Lashey's theories were false my next question was, "What is the location of memories?"

Implicitly permeating my questions is the question, "If some functions are specific to a location in the brain, what general (distributed) function co-ordinates the specific (non-distributed) functions? Given that sentient beings move about in an organized purposeful way it seems reasonable that there would be a corresponding general and co-ordinating neural function. Memory (and implicitly learning and skill) would seem to be likely candidates.

Although I'm sure Crick is a very skilled biologist I find his philosohical perspective problematic. He divides the brain into two parts, a conscious part and a non-conscious computational part (p. 265ff) The non-conscious computational part causes "decisions". The "decisions" *appear* to the conscious part as "free" although really they are not free.

There are many problematic implications to that frame. It has a Kantian flavour, namely, we know a thing as it appears to us, but not as it is in itself. If so, how could we know anything?

Further, Crick's view has a dualistic conscious/ non-conscious structure. But, I surmise, if there is a function(s) (eg memory, learning, skill) distributed across both parts the duality is mitigated...the conscious/non-conscious becomes to a degree a conventional distinction and not a natural boundary.


-- John Hedlin (, February 07, 2002.

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