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Karl Spencer Lashley 1890 - 1958

Citation: Bartlett, F.C. (1960). 'Karl Spencer Lashley: 1890-1958', Biographical Memoirs of Fellows of the Royal Society 5: 107-118.

In July 1949 the Society of Experimental Biology and the Institute of Animal Behaviour together organized a Symposium for the discussion of a wide range of problems, neurological, physiological and psychological, in which the members of both groups were interested. The Symposium was held in the Zoological Laboratory of the University of Cambridge. K. S. Lashley came to England for this meeting, and no member of the large audience who heard him describe how he had set out 'In search of the engram', and what its upshot had been, is likely ever to forget the tremendous impression that he made.

After the public discussions one morning, I walked with him back from the Zoological Department to Corpus Christi College, where he was staying. The sun shone with unclouded brilliance, and when we reached the College Lashley, who seemed, perhaps, a little tired, sat himself down on the stone steps leading to the main gate, one long leg stretched out towards the pavement, with not a single care for the curious, and slightly shocked glances of some of the passers-by. We were talking, not about any intricacies of animal behaviour, but about sailing and the sea, which he loved. He told me something about his own boats, and journeys he had made in them; but more about longer and unconventional voyages in small tramp steamers which took a long time, wherever they were going, and called at ports little known to the big luxury vessels for which he had no use at all.

Here was Lashley, sitting where hardly anybody ever did sit, talking quietly and naturally about things that I suppose very few, if any, of the others who came to that conference could, or would, talk about. It was an occasion which I am glad that I can remember. For, as I see them, all Lashley's scientific explorations, most of them planned and carried out with infinite care, and all the exercise of his superb intelligence, were a prolonged and serious adventure. In his experimental and theoretical work, and in his life outside the laboratory as well, he would go where he wanted, he would say what he believed, not because he was insensitive to influences from other people, but because his only ultimate compulsion came from inside himself.

Lashley was born in Davis, West Virginia, on 7 June 1890. In some notes which he made about his ancestry he wrote 'Lashley is an old English name and the family is certainly of English descent. To judge from their distribution Lashleys were probably early immigrants to the Carolinas and spread from there, but I have no definite information beyond the third generation. My [108] great-grandfather, Henry Lashley, was in the tanning and brick-making business, with interests in farming'. Karl's grandfather developed further various trading activities, and in due course established his father, Charles Gilpen Lashley (1860-1938) in a general store at Davis in West Virginia. Charles Lashley had 'hoped to read medicine with a local doctor', but the opportunity did not come. 'As I knew him', wrote Karl, 'his only interests were in his business, family, and local polities'.


Lashley's mother's family also came from England, and in America engaged mainly in fairly large-scale farming. His grandmother on this side came from the family of the philosopher Jonathan Edwards, and 'it is clear that intellectual curiosity and drive descended through that maternal line. My mother, Maggie Blanche Spencer (1860-1933) started to teach in Mary­land country schools at the age of sixteen. She obtained a normal school education and a reputation for handling disorderly schools. She had a great reverence for learning, was an avid reader, and collected a library of more than 2000 volumes. Shortly after her marriage she opened a photographic studio; later she turned to painting, which was the chief interest of her later years'.

Karl was an only child. His early boyhood experiences were varied. When he was still very young, the family moved to California for a short time and then, in 1898, joined in the gold rush to the Klondike. This journey into Alaska was apparently mainly fun and adventure, for a year later they were back again and re-established in Davis. But the trip made a tremendous and lasting impression on Lashley so that twice in his later life he repeated the same journey.

One of the consequences of these early travels was that Lashley had comparatively little routine school life. This was of small moment, for obviously he learned all that was needed, both in the way of regulation school accomplishments and in effective interests, from his own mother. However, he did have four or five years at the Davis High School, and already, when he left, some of the abiding interests of his life were established. He had become a keen student of the natural behaviour of animals; he was attracted by gadgets of all kinds and was clever with his hands; he liked to get hold of a couple of logs, fasten them together, and paddle himself about on the river.

In 1905 he became a full student at the University of West Virginia. He had been somewhat undecided what subjects to specialize in, and it seemed like one of those odd chances that often happen early in a brilliant career, that took him into a course of zoology taught by the neurologist, John Black Johnston. Later he was to write: 'Within a few weeks in his class I knew that I had found my life work.' In 1906 he became a research assistant to Albert M. Reese who had succeeded Johnston. He found one day '. . . a beautiful Golgi series of the frog brain. I took these to Reese and proposed that I draw all of the connexions between the cells. Then we would know how the frog worked. It was a shock to learn that the Golgi method does not stain all cells, but I think almost ever since I have been trying to trace those connexions.' [109]

In 1910 Lashley obtained his A.B. degree, and won a teaching fellowship in bacteriology at the University of Pittsburgh, where he became Master of Science in 1911. It was during this stage that he came directly under the spell of experimental psychology. In the first place this was due to his association with Karl Dallenbach, who was himself to become a leading psychologist in America, and the tie was further strengthened when, in the following year, he enrolled for a Ph.D. at Johns Hopkins. At first he worked there chiefly with H. S. Jennings on inheritance in paramecia, but the brilliance of his promise and his rather unconventional temperament, attracted both J. B. Watson, the behaviourist, and Adolph Meyer, the outstanding psychiatrist. In 1912 he published his first paper in the Journal of Animal Behaviour. In a way this was prognostic. It was entitled 'Visual discrimination of size and form in the albino rat'. In the 1930's and early 1940's, when he was at the very height of his powers, he was to come back with a long series of penetrating experimental studies of the animal visual mechanisms and their functions.

Somewhere around 1915 Lashley definitely decided that he would make his career in psychology, and from this decision he never swerved. The psychology that attracted him, however, was not the rather prim and respectable laboratory exercises of the earlier Germans, which were being imitated in those American Universities that allowed psychology a place in the structure of their studies; and it certainly was not introspectionism run to extremes. He was now working fairly closely with J. B. Watson, and Watson was as much of an adventurer in the fields of animal and human behaviour as he was himself, though nowhere near as cautious. Lashley had had several years of training and research in zoology, together with a fair amount of anatomy and physiology, and some neurology. All of these, in their relation to the behaviour of animals, seemed to be impelling him towards an experimental examination of the directions, character and final upshot of conduction in the central nervous system. There have been plenty of psychologists who, having made a careful firsthand study of behaviour, have been willing to speculate about its underlying physiological and neurological conditions, though of these they usually could claim no more than an inadequate and second-hand knowledge. It has perhaps been still commoner for people who have come from one or more of the other biological sciences, when they get to the level of behaviour itself, to suppose that no specially controlled observation and experiments are needed. In this field, they seem to assume, nothing is required beyond the exercise of common sense or the acceptance of established views. It was a part of Lashley's great strength and originality that he was, all his scientific life, prepared and able to take one side as seriously and as experimentally as the other.

For a few years still Lashley could, and did, allow free play to a lively curiosity that took him in many different directions. Students and colleagues who knew him well then have recorded that, though what he would say or do next was highly unpredictable, there was all the time a kind of 'contagion of excitement'  about him.  With Watson he made a study of homing.  He [110] published observations on the nesting activities of the noddy and sooty terns, and on colour vision in birds. He made an excursion into human learning with an account of the acquisition of skill in archery. Washington, D.C., being easily accessible to him, he made contact with Dr S.I. Franz at St Elizabeth's hospital and two joint papers with Franz, on the effects of cerebral destruction on habit formation and retention in rats began to indicate where his future work was to lie.

In 1917 Lashley went as Instructor in Psychology to the University of Minnesota. But the conditions were not very promising and a year later he was back again in Washington, and off on another new track. He accepted a post with the U.S. Interdepartmental Hygiene Board to work with Watson on popular views about sex. Both of them seem to have got some fun out of this, but Lashley took it seriously too, and later was for a number of years a member of the N.R.C. Committee for Research on Problems of Sex.
The years of concentrated and closely directed effort were now approaching. In 1920 he was back at Minnesota as assistant professor in psychology and free from routine teaching. Four years later he became full professor. In 1926 he moved to Chicago. There he was given great freedom to pursue research, and eventually he became Professor of Psychology at the University in 1929. In 1935 he was appointed Professor of Psychology at Harvard, and then, in 1937, Research Professor of Neuropsychology, with only that amount and kind of teaching to do that he himself desired. This allowed him, in 1942, to accept also the Directorship of the already famous Yerkes Laboratories of Primate Biology. He now made his home in Florida and continued there until and after his retirement to emeritus status in 1955.

The years 1920-29 were crowded with original experimental exploration. This was by no means all along one single stream, but as he said himself he was, in the main, following his early determination to find out all he could about links and lines of connexion in the central nervous system, and their function in regard to sensory discrimination, and the formation and retention of habits in animals.

In 1929 he was elected President of the American Psychological Association and he delivered, in his Presidential address, a whole-hearted attack on those behaviour theories which derive everything from reflex actions and combinations of reflex actions. This year, also, he published Brain mechanisms and intelligence: a quantitative study of injuries to the brain (1). It was a beautifully economical summing up of his experimental work of the preceding nine years. It quickly achieved wide recognition, and whatever may eventually prove to be the finally correct story in detail of the nervous mechanisms and their functions involved in intelligent behaviour, it is certain that Lashley's work and his exposition in this monograph will remain of fundamental importance.

In this book Lashley stated his two principles of equipotentiality ('. . . The apparent capacity of any intact part of a functional area to carry out, with or without reduction in efficiency, the functions which are lost by destruction of [111] the whole. This capacity varies from one area to another and with the character of the functions involved. It probably holds only for the association areas and for functions more complex than simple sensitivity or motor-coordination', p. 25) and mass functions* ('. . . whereby the efficiency of performance of an entire complex function may be reduced in proportion to the extent of brain injury within an area whose parts are not more specialized for one component of the function than for another' loc. cit.) In view of the incautious use which commentators have sometimes made of these two principles, it is necessary to point out that they are inductive generalizations from a mass of data in which the determining neurological and physiological conditions, and their detailed issue in behaviour, were observed with equal care. They were never put forward as themselves explaining anything, but only as summarizing in a general way a great amount of penetrating experi­mental observation. His third principle, of disturbances of equilibrium within functional systems following unilateral brain lesions—to which, for some reason, less attention has been paid—is of the same order. All three principles are not explanations, but are summary statements of that which has to be explained. Lashley himself made this perfectly clear.

From now until 1955, and the onset of an obscure blood disorder, Lashley continued to live an extremely active life as an experimenter. He returned to his early interests in the mechanisms of vision, and linked closely with this many further studies of cerebral function in learning. Following his appoint­ment at Harvard, and particularly as Director of the Yerkes Laboratories, naturally more and more of his own and his students' work concerned the behaviour of primates. Always it was intelligent aspects in behaviour that compelled his attention. He remained true to his early demonstrations that intelligence operates at levels of performance—e.g. simple maze-running— which others often have tried, and still continue to try, to put into terms of an automatic conditioning process, and at the same time he was turning more frequently to somewhat general problems, and to investigations in the field of the 'higher mental processes'. It was in the line of this last approach that he gave the address ‘in search of the engram', to which I have already referred at the beginning of this notice.

To many people, and sometimes to himself, it seemed that Lashley's scientific work was issuing, or had issued, principally in negations. Professor D. O. Hebb, for example, in a very fine review of his life and work, has written 'Lashley was left in the uncomfortable position of being against (existing) theory, a persistent critic of new as well as old ideas without having others of his own which he was willing to present as an adequate substitute'. 'But', he adds immediately, 'it does not do his theoretical position justice to regard his criticism as destructive only. He clarified many problems, often by setting them in a new context that his own research or his scholarship made possible, with corresponding implications for research' (2). [112]

This is all true, but it is not all the truth. At the end of his address on the engram Lashley rather wryly said, 'This series of experiments has yielded a good bit of information about what and where the memory trace is not.' But everybody who heard him knew that, though the words may have been negative, he finished still full of the ardour of the search, still resolved that he, and others, must continue it, and that in spirit he was optimistic and positive. For anybody who looks there are, in this study as in very many others that he made, flashes of insight springing out of the level of scientific caution. It is highly probable that immediate memory is maintained by some sort of after-discharge of the originally excited neurones. Such can scarcely be the basis of more permanent memory.' No doubt others before him had made much the same suggestion but not with the same background or to the same purpose. Again, 'The serial timing of actions is among the most important and least studied of behavioural patterns.' And 'Skilled acts involve a timed series of actions which cannot be accounted for as a simple chain of conditioned reflexes.' We have to keep in mind that for him these suggestions, of memory, for example, as a skill, and of all skills as timed series of actions were not merely general notions gained by reflection. They were a summing up of a great mass of original, highly controlled observations; and since Lashley made them their definition and significance have increased.

Lashley possessed indeed, extreme scientific honesty and carefulness, combined both with outstanding technological and manipulative skill, and with a capacity for brilliant intuition. The first two, working in fields full of hastily framed hypotheses and theories, were bound to issue largely in destructive criticism. Scientific intuition, reaching forward towards discovery before the evidence which will compel everybody is known, is always preponderantly positive. It is beyond any possibility of dispute that in each of these ways Lashley's achievements will remain of permanent and outstanding significance. At the same time it is highly probable that many of his suggestions which could not at the time be fully substantiated, of the remarks which he seemed to make 'by the way' and of his flashes of insight will be found to have contributed most of all towards the solution of his problems.

Lashley had honorary degrees from the Universities of Pittsburgh, Chicago, Western Reserve, Pennsylvania and Hopkins. He was a member of the American National Academy of Sciences, of the American Philosophical Society and of the American Academy of Arts and Sciences. He served on the National Research Council (division of anthropology and psychology) in 1927-30, and 1932-5. He belonged also to the American Society of Zoologists, the American Physiological Society, the Society of Experimental Psychologists, and the American Society of Human Genetics. He was an Honorary Member of the American Neurological Association, the Harvey Society, the New York Academy of Sciences, the British Institute for the Study of Animal Behaviour, and Honorary Fellow of the British Psychological Society. In 1951 he was elected a Foreign Member of the Royal Society. He was awarded the Crosby Warren Medal by the Society of Experimental Psychologists, the [113] Daniel Giraud Medal for Zoology by the National Academy of Sciences and the William Baly Medal for Physiology by the Royal College of Physicians.

In 1954 Lashley fell seriously ill with a difficult anaemic condition. After prolonged and drastic treatment he seemed to have recovered and in 1957 he made, with his wife, his third and final trip to Alaska. The following year they came to England and to London, and on 28 July he signed the Charter Book of the Royal Society. They then went to France and, at Poitiers, on 7 August 1958, he died suddenly.

Lashley was twice married. His first marriage was to Miss Edith Ann Baker, in 1918. She was an excellent pianist, and he had taught himself to play the violin and the 'cello. Since 1920, he wrote later, he had 'devoted at least one evening a week to the playing of chamber music, of which I have collected an extensive library'. There is an authentic story that one evening at Minne­apolis, a dozen or so people at the Lashleys' talked of how much a person would be willing to sacrifice for the sake of his research. One of the guests said, 'Karl, would you be willing never to hear a bar of music if, by giving it up, you could find out what you want to know?' He said, rather casually, 'Yes'. 'Not Beethoven!' his friend insisted. 'Yes', Karl replied, much less casually, 'I'd be willing to be deaf for the rest of my life' (3).

His second great hobby was sailing, and his interest in this went far back to the days of his boyhood. At various times he owned a number of boats from a Star to a 36-foot yawl, and several of these contained original features which he had himself designed and constructed. He sometimes said that he would have liked best of all to venture out upon some long and lonely voyage across wide seas. It was partly his interest in boats that made him highly skilled with his hands. He thoroughly enjoyed designing and building apparatus and doing carpentry and cabinet making, and he w7as an accomplished chef. He liked chess and played it well, and it was, no doubt, due to an underlying whimsical sense of fun which never left him, that he got a lot of pleasure from nonsense poetry, invented limericks, and wrote masses of rhyming verse.

His first wife died in 1948, and in 1957 he married Claire H. Schiller, the widow of the distinguished psychologist, Dr Paul H. Schiller. It is of interest that almost the last considerable contribution that Lashley made to psych­ology was to write an introduction to a book on Instinctive behaviour which was translated and edited by his second wife. Paul Schiller had made some important observations on insightful behaviour in primates, and of this Lashley now wrote: 'The insight is the immediate one-trial learning to use the innate manipulative acts in the manner discovered by chance, and the generalization of the acts to other, similar situations . . .; an extension of the same concepts to the manipulation of ideas may well lead to the conclusion that man has failed to identify his own instincts because he calls them intelligence' (4). In what sense, if at all, this is true may be decided in the future. [114] It shows that Lashley's flair for the intuitive flash remained active, and combined with his devotion to meticulous control to the end of his life.

In appearance Lashley was rather tall, and rather loosely built. He had a sensitive and expressive face, maybe a little sad in repose, but capable of lighting up into a most charming smile. Wherever he was present he could not be overlooked at the time, or soon forgotten. This was not, generally, because he talked a lot or pushed himself forward in any way; it was because he was one of those rare folks from whom a kind of excitement seems to spread out. Some found him shy, reserved and even stand-offish. Certainly he had little relish for the company of the unintelligent or the pretentious, and he did not love convention for convention's sake. But when he met a person, or faced an audience, whose intelligence and honesty could make some sort of a match with his own, he could be splendidly witty, gay and wise. No doubt there were ways in which rebels attracted him. At various stages he was much interested in J. B. Watson, in Pavlov, in Freud and in the Gestalt psycho­logists—all at odds against the respectable opinions of their day and clime. But he maintained his own integrity and was never swept away by any of them, for with a certain liking for intellectual risk and sweeping assertion he combined the scientist's loyalty to empirical observation and respect for experimental facts.
I wish gratefully to acknowledge the valuable assistance which I have received in the preparation and writing of this memoir from Mrs Lashley, and from a number of my American friends and Professor Lashley's colleagues. Mrs Lashley allowed me to use some notes written by her husband, and gave me much further information. She also provided the Bibliography. For the photograph and the signature I am indebted particularly to Professor E. G. Boring and to Harvard University, Dr Leonard Carmichael, Secretary of the Smithsonian Institution, and Professor Donald O. Hebb of the University of Montreal allowed me to make use of memoirs which they had written for the American Philosophical Society and the American Journal of Psychology.

F. C. Bartlett


(1) University of Chicago Press.
(2) The phrase generally used by Lashley and by others following him is 'mass action'. t Amer. J. Psychol., March, 1959, Vol. 72.
(3) For this anecdote I am indebted to Mrs Lashley.
(4) Quoted from a memoir written by Dr Leonard Carmichael and published in the American Philosophical Society Tear Book for 1958.


1911.  The bacteriology of eggs with special reference to the mode of contamination. Unpublished thesis for M.S. degree, Univ. of Pittsburgh.

1912. Visual discrimination of size and form in the albino rat. J. Animal Behav. 2, 310-331.

1913. (With H.  S. Jennings.)  Biparental inheritance and the question of sexuality in Paramecium. J. exp. Zool. 14, 393-466. 1913. 

1913 (With H. S. Jennings.) Biparental inheritance of size in paramecium. J. exp. Zool. 15, 193-200.

1913.  (With J. B. Watson.) Notes on the development of a young monkey. J. Animal Behav. 3, 114-139.

1913. Reproduction of inarticulate sounds in the parrot. J. Animal Behav. 3, 361-366.
1913.  (With J. B. Watson.) Literature for 1912 on the behavior of vertebrates. J. Animal Behav. 3, 446-463.
1914.  A note on the persistence of an instinct. J. Animal Behav. 4, 293-294.

1914. Recent literature of a general nature on animal behavior. Psychol. Bull. 11, 269-277.

  1. (With J. B. Watson.) An historical and experimental study of homing. Carnegie Inst.

Wash.7, Pub. 211, 9-60. 1915. Notes on the nesting activities of the noddy and sooty terns. Carnegie Inst. Wash. 7,
Pub. 211,61-83. 1915. The acquisition of skill in archery. Carnegie Inst. Wash. 7, Pub. 211, 107-128. 1915. Inheritance in the asexual reproduction of Hydra viridis. Proc. Nat. Acad. Sci., Wash.1,298-301.

1915. Recent literature on sensory discrimination in animals. Psychol. Bull. 1915, 12, 291-299.

  1. Inheritance in the asexual reproduction of Hydra. J. exp. £ool. 19, 157-210.
  2. Results of continued selection in Hydra. J. exp. £ool. 20, 19-26.

1916.  (With S. O. Mast.) Observations on ciliary current in free-swimming paramecia.
J. exp. Zool. 21, 281-293.

1916. The color vision of birds. I. The spectrum of the domestic fowl. J. Animal Behav. 6, 1 -26.

1916. Sensory physiology of animals. Psychol. Bull. 13, 309-315.

1916. The human salivary reflex and its use in psychology. Psychol. Rev. 23, 446-464.

  1. Reflex secretion of the human parotid gland. J. exp. Psychol. 1, 461-493.
  2. Changes in the amount of salivary secretion associated with cerebral lesions. Amer. J.

Physiol. 43, 62-72.

1917. The accuracy of movement in the absence of excitation from the moving organ. Amer. J. Physiol. 43, 169-194.

1917.  (With S. I. Franz.) The retention of habits by the rat after destruction of the frontal portion of the cerebrum. Psychobiol. 1, 3-18.

1917. Sensory physiology of animals. Psychol. Bull. 14, 276-283.

1917.  (With S. I. Franz.) The effects of cerebral destruction upon habit-formation and retention in the albino rat. Psychobiol. 1, 71-140.

1917. The effects of strychnine and caffeine upon the rate of learning. Psychobiol. 1, 141-170.

1917. The criterion of learning in experiments with the maze. J. Animal Behav. 7, 66-70. 1917.  (With H. B. Hubbert.) Retroactive association and the elimination of errors in the maze. J. Animal Behav. 7, 130-138.

1917. A causal factor in the relation of the distribution of practice to the rate of learning. J. Animal Behav. 7, 139-142.
1917. Modifiability of the preferential use of the hands on the rhesus monkey. J. Animal Behav. 7, 178-186.
1918. A simple maze: with data on the relation of the distribution of practice to the rate of learning. Psychobiol. 1, 353-367

  1. Sensory physiology of animals. Psychol. Bull. 15  280-287.
  2. (With J. D. Dodson.) Sensory physiology of animals. Psychol. Bull. 16, 159-164.
  3. Studies of cerebral function in learning. Psychobiol. 2, 55-135.

1920.  (With J. B. Watson.) A consensus of medical opinion upon questions relating to sex education and venereal disease campaigns. Mental Hyg. 4, 769-847.

  1. Sensory physiology of animals. Psychol. Bull. 17, 178-187.
  2. Studies of cerebral function in learning. II. The effects of long continued practice upon localization. J. comp. Psychol. 1, 453-468.
  1. Studies of cerebral function in learning. III. The motor areas. Brain, 44, 255-286.
  2. (With J. B. Watson.) A psychological study of motion pictures in relation to venereal disease campaigns. Pub. Interdepartmental Social Hygiene Board, U.S. 1-88.
  3. 1922.  Studies of cerebral function in learning. IV. Vicarious function after destruction of
    the visual areas. Amer. J. Physiol. 59, 44-71.
    1923.  The behavioristic interpretation of consciousness. Psychol. Rev. 30, 237-272; 329-353.

1923.  Temporal variation in the function of the gyrus precentralis in primates. Amer. J. Physiol. 65, 585-602.
1924.  Studies of cerebral function in learning. V.  The retention of motor habits after destruction of the so-called motor areas in primates. Arch. Neurol. & Psychiat. 12, 249-276.

1924. Physiological analysis of the libido. Psychol. Rev. 31, 192-202.

1924. Studies of cerebral function in learning. VI. The theory that synaptic resistance is reduced by the passage of the nerve impulse. Psychol. Rev. 31, 369-375.

1926. Studies of cerebral function in learning. VII. The relation between cerebral mass, learning and retention. J. comp. Neurol. 41, 1-58.

1926.  (With D. A. McCarthy.) The survival of the maze habit after cerebellar injuries. J. comp. Psychol. 6, 423-433.

1929.  (With J. Ball.) Spinal conduction and kinesthetic sensitivity in the maze habit. J. comp. Psychol 9, 71-105.

1929. Brain mechanisms and intelligence. Chicago: Univ. of Chicago Press, xiv+215.
1929. Learning:  I.  Nervous mechanisms in learning.  In   The foundations of experimental psychology. (C. Murchison, Ed.), Worcester, Mass.: Clark Univ. Press, 524-563.
1930. Basic neural mechanisms in behavior. Psychol. Rev. 37, 1-24.
1930. The mechanism of vision. I. A method for rapid analysis of pattern-vision in the rat. J. genet. Psychol. 37, 453-460.

1930. The mechanism of vision. II. The influence of cerebral lesions upon the threshold of discrimination for brightness in the rat. J. genet. Psychol. 37, 461-480.
1930. The mechanism of vision. III. The comparative visual acuity of pigmented and albino rats. J. genet. Psychol. 37, 481-484.
1931. The mechanism of vision. IV. The cerebral areas necessary for pattern vision in the rat. J. comp. Neurol. 53, 419-478. 1931. Cerebral control versus reflexology: a reply to Professor Hunter. J. gen. Psychol. 5, 3-20.

Mass action in cerebral function. Science, 73, 245-254.

The mechanism of vision. V. The structure and image-forming power of the rat's eye.J. comp. Psychol. 13, 173-200.

1932.  (With M. Frank.) The mechanism of vision. VI. The lateral portion of the area striata in the rat: a correction. J. comp. Neurol. 55, 525-529. 1932. Studies of cerebral function in learning. VIII. A reanalysis of data on mass action in the visual cortex. J. comp. Neurol. 54, 77-84.
1932.  Massenleistung  und   Gehirnfunktionem.    Nervenarzt.   5.  Jahr.,   Heft   3,   113-120; 180-184.
1933.  (With L. E. Wiley.) Studies of cerebral function in learning. IX. Mass action in relation to the number of elements in the problem to be learned. J. comp. Neurol. 57, 3-56.

1933.  (With W. T. McDonald and H. N. Peters.) Studies of cerebral function in learning. X. The effect of dilatation of the ventricles upon maze-learning. Amer. J. Physiol. 104,51-61.

Integrative functions of the cerebral cortex. Physiol. Rev. 13, 1-42.

Learning: III. Nervous mechanisms in learning. In A handbook of general experimental psychology. (C. Murchison, Ed.), Worcester, Mass.: Clark Univ. Press 456-496.

1934. The mechanism of vision. VII. The projection of the retina upon the primary optic centers in the rat. J. comp. Neurol. 59, 341-373. 1934. The mechanism of vision. VIII. The projection of the retina upon the cerebral cortex of the rat. J. comp. Neurol. 60, 57-79.

1934.  (With M. Frank.) The mechanism of vision. X. Postoperative disturbances of habits based on detail vision in the rat after lesions in the cerebral visual areas. J. comp. Psychol. 17, 355-391.

1934.  (With J. T. Russell.) The mechanism of vision. XI. A preliminary test of innate organization. J. genet. Psychol. 45, 136-144.

1935. Studies of cerebral function in learning. XL The behavior of the rat in latch box situations. Comp. Psychol. Monogr. 11, 1-42. 1935. The mechanism of vision. XII. Nervous structures concerned in the acquisition and retention of habits based on reactions to light. Comp. Psychol. Monogr. 11, 43-79.

1937. The mechanism of vision. XIII. Cerebral function in discrimination of brightness when detail vision is controlled. J. comp. Neurol. 66, 471-480.

1937. The mechanism of vision. XIV. Visual perception of distance after injuries to the cerebral cortex, colliculi, or optic thalamus. J. genet. Psychol. 51, 169-207.

  1. Functional determinants of cerebral localization. Arch. Neurol. & Psychiat. 38, 371-387.
  2. The thalamus and emotion. Psychol. Rev. 45, 42-61.

1938. The mechanism of vision. XV. Preliminary studies of the rat's capacity for detail vision. J. gen. Psychol. 18, 123-193.

1938. Conditional reactions in the rat. J. Psychol. 6, 311-324.

1938. Experimental analysis of instinctive behavior. Psychol. Rev. 45, 445-471.

1938. Factors limiting recovery after central nervous lesions. Hughlings Jackson Memorial Lecture, Montreal. J. nerv. ment. Dis. 88, 733-755.
1938.  The mechanism of vision. IX. The numerical relations of cells in the visual system of the rat. Ukrainian Psychoneur. Acad.
1939.  The mechanism of vision. XVI. The functioning of small remnants of the visual cortex. J. comp. Neurol: 70, 45-67.

  1. Studies of simian intelligence from the University of Liege. Psychol. Bull. 37, 237-248.
  2. Coalescence of neurology and psychology. Proc. Amer. Phil. Soc. 84, 461-470.

1941. Patterns of cerebral integration indicated by the scotomas of migraine. Arch. Neurol. & Psychiat. 46, 331-339.

1941. Thalamocortical connections of the rat's brain. J. comp. Neurol. 75, 67-121.

  1. Correlated developments in neurology and psychology. Science, 93, 465-466.
  2. An examination of the 'continuity theory' as applied to discriminative learning

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