SYMPOSIUM: Recollections of B. F. Skinner Introduction J.M. HARRISON
Boston University It is fitting that Skinner be honored by a society honoring Pavlov. Pavlov and Skinner each published a book of profound importance. Pavlov published Conditioned Reflexes in 1927 and only eleven years later, in 1938, Skinner published The Behavior of Organisms. Both books carried a number of similar original messages. Both Pavlov and Skinner treated psychology as an objective experimental natural science in which behavior was the datum. Both books were descriptions of the results of a long series of highly original experiments, the experimental problems being empirically derived, that is, based upon the results of prior experiments. Both placed their work in an evolutionary context, substituting Darwin's notion of continuity of mind with continuity of behavior, and making no fundamental distinction between man and other species. The most important similarity between the work of Pavlov and Skinner, a similarity that rarely receives comment, is that both reported experiments designed to demonstrate behavioral phenomena in the single animal. This requires great emphasis upon the details of the experiments themselves, with continual alteration and refinement of experimental procedures. Both eschewed group studies, statistics and formal hypothesis testing experimental designs. The major strength of this approach is that it leads to scientific discovery in a way that formal experimental design does not. In the hands of both Pavlov and Skinner new behavioral phenomena continually emerged as each worker progressed from experiment to experiment, investigating at many stages what were frequently unexpected findings (Skinner, 1956). The Behavior of Organisms was highly original in the historical context in which it appeared, and the approach and content of the book received considerable hostile comment. The difficulty of getting editors to accept papers on operant conditioning ultimately led, in 1957, to the founding of The Journal of Experimental Analysis of Behavior by Skinner and his associates. Skinner was a great admirer of Pavlov as shown by the 44 references he made to Pavlov in The Behavior of Organisms. Pavlov, in Conditioned Reflexes, approved of Thorndyke's (sic) The Animal Intelligence (1898) as the starting point of the experimental study of behavior, and he saw the American "Behaviorists" as the only representatives of the objective approach in psychology. Had Skinner been active at this time, I am sure Pavlov would also have quoted him with approval.
Address correspondence to: J. M. Harrison, Department of Psychology, Boston University, 64 Cummington Street, Boston, MA 02215. Integrative Physiological and Behavioral Science, July-September, 1992, Vol. 27, No. 3, 258-266
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Burrhus Frederick Skinner J. V. BRAD~"
Johns Hopkins School of Medicine When I was a graduate student I presented a paper at a psychological meeting which Skinner attended. At the conclusion of the session, Skinner congratulated me on the work and invited me to lunch. Since then I have worked on the experimental analysis of behavior. Fred Skinner was born on March 20th, 1904, in Susquehanna, Pennsylvania. He was the first child of Grace Burrhus, a "bright and beautiful woman," and William Skinner who "read law" and, as a draftsman for the Erie Railroad, wrote a text on "Workman's Compensation Law." Fred Skinner lived in the house where he was born until he went to college, having graduated from the same high school from which his mother and father graduated. He developed strong literary and artistic interests at home and majored in English at Hamilton College, in Clinton, New York. He received a Bachelor's degree Phi Beta Kappa and an award for classical Greek. He also, with encouragement from Robert Frost, tried his hand at writing. He spent six months of bohemian living in Greenwich Village, and a summer in Paris which, at that time, was full of literary expatriots. He returned and entered Harvard to study psychology because he felt that he had nothing to say as a writer. He submitted a thesis on the concept of the reflex and received his Ph.D. in 1931 and then became a National Research Council Postdoctoral Fellow with W. J. Crozier and worked on the central nervous system in the General Physiology Department at Harvard Medical School. From his laboratory over the next five years he produced the data for his first major treatise, The Behavior of Organisms (1938), completed when he was little more than thirty years old. By 1936, Fred had married Yvonne Blue, an English major from the University of Chicago, and had moved to the University of Minnesota where he remained for the duration of the war. While there, he attempted, without success, to interest the war office in the use of pigeons to guide bombs to designated marine targets (Pigeons in a Pelican). When his second daughter Julie was born he constructed the famous "baby box" designed to mechanize early child care (Skinner, 1945b). While at Minnesota, he also started work on Walden Two (1948), his utopian strategy for community living. In 1945 he moved to Indiana where he became chairman of the Department of Psychology. Three years later, in 1948, he moved back to Harvard. He remained at Harvard, after briefly considering a move to the University of California at La Jolla in the 1960s, until his death in 1990. The early days in the physiology laboratory had stimulated Skinner's abiding interest in verbal interactions, which culminated in a major contribution about 25 years later. During this time he received two Guggenheim Fellowships, took a summer course at Columbia, and gave the William James lectures at Harvard, all of which became the book, Verbal Behavior (1957). This book produced a storm of protest led by the most prominent of the linguistic scholars. Skinner's response (quite typical) to an inquiry regarding the most influential of the critical reviews was that he had read the first few paragraphs, realized the reviewer had missed the point and put it aside to return to more useful pursuits. Skinner's major contribution concerned the conceptual analysis of behavior. He considered the problem of understanding behavior to revolve around the identification of a unit of analysis, and chose as the unifying theme, the lever press, which he developed in the Behavior of Organisms, his book that made a tremendous impact upon experimental psychol-
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ogy. The methods developed in this book are still used by both psychologists and neural scientists who study behavior. Skinner insisted on the study of behavior for its own sake, and believed that it was the relationship between behavior and the environment that had to be explained. He strongly objected to mentalistic explanations which sought to explain behavior by recourse to an unexplained mental apparatus or a conceptual nervous system. However, he realized that events occurred in the body, that the skin was not a barrier to the analysis of "private events," and that such events had to be analyzed in a complete system of psychology. In a volume published a year before his death, he addressed a broad range of topics including: Cognitive thought; the initiating self concept; rule governance; and genes and the evolution of social behavior. Skinner is most widely quoted for the extension and application of his ideas to human behavior. The same analytical strategies that characterized Skinner's work have been applied in clinical settings. This had a demystifying effect upon the domains of psychotherapeutie intervention. Further applications led to the development of teaching machines, programmed instruction, and community treatments for juveniles. The greatest impact has been upon the majority of the institutions for the mentally retarded, in which behavioral analytic principles have made a major contribution to the mental health management of these people. Skinner was a controversial figure throughout his career and he remained an alert, reflective and feisty scholar who gave no quarter when confronted by those who would threaten the intellectual integrity of his field. He fought leukemia while continuing to write and even lecture on rare occasions, and gave his final address at the 98th convention of the American Psychological Association when accepting a citation for Outstanding Lifetime Contributions. In the course of that lecture he aimed one last salvo at those who, in the absence of observable representations of reality, have resorted to "theories about what is going on in the head of the mind," labeling currently fashionable "cognitive science" as the "creationism of psychology" ! He sent the manuscript based on this lecture to the American Psychologist the evening before he died. The measure of the man is perhaps nowhere more clearly reflected than in the following excerpt from a letter Skinner sent to me when he was starting his leukemia treatment. So long as I get platelets and red cells I feel perfectly normal. But, of course, in the not too distant future, some silly infection will take me off. I've had a good life, and it would be rather ungracious to complain, don't you think?
Skinner's View of Organism CHARLESCATANIA
University of Maryland, Baltimore I was an undergraduate at Columbia where I also obtained an MA working with Schoenfeld and Keller. Keller was a close friend of Skinner, and it was natural that I should move to the old psychology department at Harvard to obtain a Ph.D. under Skinner. I maintained a continuous close connection with Skinner until his death. In Skinner's first book, The Behavior of Organisms (1938), his interest in biology is seen in his use of the word "organism" (after Loeb's "The organism as a whole"), as indicating animals in general, including man, to whom he thought his work on the rat was directly
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relevant. In Science and Human Behavior (1953), he strengthened his ties with biology, particularly with respect to Darwin's ideas of natural selection by the environment of the behavior of the species (phylogenie selection). Skinner visualized three modes of selection of behavior by the environment; Darwinian (phylogenic selection), ontogenic selection of the behavior of each individual due to the environmental consequences of the behavior, and cultural selection (Skinner, 1981). Natural selection refers to Darwin's account of evolution in terms of the differential survival and reproduction of the varied members of a population; the environment naturally selects certain behavioral (and other) variations over others, and these are passed on to subsequent generations. The mechanism of transmission is genetic and the source of variation is mutation. Skirmer's ontogenic selection operates over the lifetime of the individual animal, environmental consequences selecting, in this case, from behavioral variation in the individual. "In both operant conditioning and evolutionary selection of behavioral characteristics, consequences alter future behavior. Reflexes and other innate patterns of behavior evolve because they increase the chances of survival of the species. Operants grow strong because they are followed by important consequences in the life of the individual" (Skinner, 1953, p. 90). Through phylogenic mechanisms operating over generations, the behavior of a parent can survive in the behavior of its offspring. Through ontogenic mechanisms operating over the lifetime of a single organism, some types of behavior are more likely than others to survive in that organism's behavior. When the offspring can acquire behavior from the parent or from any other organism (e.g., through observation, imitation of verbal behavior), a third area for selection is created, cultural selection. Skinner's third variety of selection, cultural selection, occurs when behavior, particularly verbal behavior, is passed on from one individual to another. For example, what someone has written could survive that person's death if it is read by others. Such shared verbal behavior is part of the culture of the group. One significant consequence of Skinner's cultural selection, was that it led to the analysis of how scientific and other vocabularies are established and maintained. Such an analysis does not proceed in terms of grammatical or linguistic structures, but in terms of the antecedents and consequences of verbal behavior. It is frequently assumed that a major function of verbal behavior is to communicate feelings, thinking or emotions. This assumption is untenable because verbal communities can not create and maintain vocabularies based upon such events. However, we learn to talk of some private events from the same verbal community that teaches vocabularies dealing with public events. The teaching of such a vocabulary can be based only on what is mutually accessible to listener and speaker, that is, overt events correlated with the private event. Private and public events are assumed to have the same kind of physical dimensions. A parent can teach a child color names because both parent and child can see the colors, and the parent can correct the child's response. Likewise, a vocabulary of private events can be taught only from terms based upon events to which the verbal community has access. For example, a child may learn to use the word "pain" because the parents have access to the events which caused an injury and the child's crying or facial expression. Reports of private events can be no more reliable than the public events correlated with them. Some verbal responses may be determined, not by a private event, but by observation of one's own behavior. For example, the observation that one is eating voraciously may lead to the conclusion that one is hungry. Here, one is saying of one's self what would be said of another eating equally voraciously. These examples show that Skinner's analysis of private events (Skinner, 1945a) must apply to all psychological terms. Vocabularies of all kinds are not based on linguistic rules,
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for example, but upon the consequences of behaving verbally. The essential questions are, how could the words have been learned and how could they have been taught? Skinner was told he had leukemia after receiving a bone marrow test following an attack of angina. When given only two months to live he described his reactions in an interview on National Public Radio in 1990: I am not religious, so I don't worry about what will happen after I am dead. And when I was told that I had this and would be dead in a few months, I didn't have any emotion of any kind at all. Not a bit of panic, or fear, or anxiety. Nothing at all. The only thing that touched me was, and really, my eyes watered when I thought of this, I will have to tell my wife and daughters. You see, when you die you hurt people, if they love you. And you can't help it. You have got to do it. And that bothered me. But otherwise, my dying, I knew I was going to die. N o w I know about when. I've had a very good life. It would be very foolish of me to complain, in any way, about it. So I'm enjoying these last few months as well as I ever enjoyed life. Later in the interview, Skinner added the following: It's very curious, is leukemia. I recommend it as a terminal illness, because if you get blood then you're perfectly normal, except that the white cells deteriorate, and eventually you are extremely vulnerable to infection, and that's why my wife may have asked you to wash your hands or something, I don't know. It's silly because the doctor tells me probably what you will die of is something you already have in you, but it will suddenly have a field day and it'll be the end. Something like pneumonia or something. But until that last couple of days you are perfectly healthy. I first heard about Skinner's leukemia about a month after the radio interview. At that time I was corresponding with Skinner about a paper that appeared in the American Psychologist, and Skinner's letter (of Jan. 15th, 1990) included the following paragraph: The leukemia is something of a nuisance. I have to go over once a week or so for transfusions and whatnot and have recently had a vascular access catheter put in on my chest to avoid getting needles into large veins on each occasion. I am feeling fine and enjoying life, though I am not getting as much done as I once did. The following appeared in a later letter dated 10th Feb. 1990: The leukemia is under control in one sense; so long as I have transfusions of platelets and red cells, I feel perfectly normal. However, my white count is going way up and that means that my resistance is declining. Although I will feel fine up to the end, something or other will take me off in a hurry, so I am told. I've had a good life and this doesn't bother me too much. The last letter I received from Skinner was dated 12th July 1990 and included the following comment: "The critical episode in the leukemia a couple of weeks ago has put me back .... Wish I had time for more but that's that."
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Skinner accepted an award for a lifetime of achievement from the American Psychological Association on the 10th of August, 1990, and this was to be his last public appearance. He died on August 18th, 1990, while in the hospital. "Near the end, his mouth was dry. Upon receiving a drink of water he said his last word, 'marvelous' " (Vargas, 1991, p.2). A few days after Skinner's death I received transcripts of letters Skinner had written to A. P. Saunders, one of his Hamilton College professors, with the comment "Dear Charlie, Hope this amuses you. Fred" A letter to Saunders dated 16th August 1926, contains the following striking passage: Just before commencement (June 1) my grandfather Burrhus was operated upon by my friend the doctor for enlarged prostate. Two weeks later he was again operated on for hydrocele. Despite his age (77) he recovered rapidly and about the first of July came to our home to convalesce. While he was here I attended to all his dressings--which were numerous--and we got to know each other well. He was having some trouble with his s o n - - m y uncle--and he confided completely in me and gave me credit for straightening the affair out. He would let no one else do anything for him but me. After he was home here a week he took cold, went out of his head in a day or so and 3 days later died of bronchial pneumonia. For a day and a half I watched h i m - - h e was apparently awake yet unconscious save for neuralgic pains--he hiccoughed badly--until the last evening they gave him morphia. This depressed his lungs which brought on coughing and his right lung filled completely within an hour. Then all night long this organism--worn out, beyond repair lay there. Certain muscles of diaphragm went on functioning--a little air was pulled spasmodically into the remaining lung space. An overtaxed heart--sustained on strychnine--pumped impure blood--and gave out under the strain. His pulse weakened--he coughed a bit and lay still. I listened to his heart--it was still. I lifted him u p - - a little black fluid ran from his lips.
I watched this human organism wear out--watched it as unemotionally as possib l e - a n d tried to understand it. What had happened. The active idea which I had known as my grandfather was gone simply because certain physical properties of the body had given out. Was there anything more of him beside that, something spiritual? If so when did it leave him? At the last moment?--except for certain reflex muscular activities the minute before and the minute after were alike.
I am very sure that my grandfather--all of him--all that I knew of him and felt--his character, personality, emotions, skill, desires,--all--everything went as soon as the physical condition of his body became unfit for certain nervous coordinations. Just as the dreary character of the clock I now hear will vanish when the parts which give forth its ticking shall stop.
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Skinner at Work PETER D~ws
Harvard University Medical School In the 1950s Skinner was looking for someone interested in the behavioral investigation of pharmacological substances. I replied that I was and thereupon, in 1952 embarked on a new era in the behavioral investigation of drugs based on Skinner's ideas. After Skinner received his Ph.D. in psychology at Harvard, he stayed on as a Junior Fellow at the Society of Fellows. He was given space by Crozier in the Department of Biology. He also spent some time in the Department of Physiology at Harvard Medical School, where he probably knew Alexander Forbes, Hallowell Davis, Walter B. Cannon and Arturo Rosenbleuth. As the result of these early experiences, Skinner at work was more like a physiologist than a psychologist. He walked to work at Memorial Hall at the same time every morning. When he reached the Pigeon Laboratory in the basement, Charles Ferster would be waiting for him and they would go straight to work. Skinner believed in arranging the environment to help him do what he wanted to do. When in the laboratory he wanted to work, and made the ambience of the laboratory the discriminative stimuli for working. Any other activity would not be allowed. Different types of work were associated with different parts of the laboratory. When in the room where the pigeons worked, he was concerned with them, when in the workshop he was concerned with the design of some apparatus, and so on. If something else was to be discussed, then he would leave the room and talk in the corridor. The purpose of these arrangements was not to maximize work, but to maximize accomplishment at minimum effort. In the late 1920s and early 1930s, he worked long hours and weekends because that was the only way he could get results. He had no automated equipment, no Ferster, Morse, or Gollub to perform the routine chores of running experiments, and he had to make all the apparatus himself. He was fascinated by where his results were leading him, and impatient for more, and so worked all the time. All was different in the 1950s. He had resources to have as many experiments running in parallel as he wanted, automation had advanced and he had a Ferster or Morse to oversee the experiments, and Mrs. Papp to put the pigeons in the boxes. When he no longer needed to work all the time his working day usually ended by noon. The laboratory was in operation throughout a 24-hour day. The apparatus consisted of relays, timers, counters, and other devices mounted on black plastic panels equipped with fuse clips. The panels could be snapped onto the three or four rows of parallel brass rods that supplied the power, at 28 Volts DC or 110 Volts AC. Programming circuitry was made with snap leads interconnecting the timers, counters and other items. One or two cumulative records were connected to each apparatus. On a lower shelf stood the pigeon box: A Sears Roebuck aluminum picnic ice box. Inside, the partition that Sears provided to separate the ice block from the picnic materials was used to hold the key to peck, Christmas tree lights as visual stimuli and a Gerbands magazine to present grain as required: on the other side, the pigeon. The behavioral part of the apparatus was all original with the laboratory, and was constantly evolving. Pigeon keys were in large square mounts in 1953, but the rectangular keys with their wiping contacts appeared not many years later. The longest evolution occurred in the cumulative recorder. In 1950 recorders were large wooden boxes in which the pen was
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moved across the paper by friction on a string. Gerbrands, who worked in the psychology department machine shop, started manufacturing cumulative records and other apparatus in his garage. When that enterprise prospered he left Skinner to devote full time to his own company. Skinner was good at developing devices that worked, and then continuing to improve them. But it was characteristic of the atmosphere of the laboratory that n o b o d y - Skinner, Morse, Ferster or Gerbrands--claimed credit for any particular advance. As the decade of the '50s progressed there was a steady erosion of Skinner's personal involvement in individual experiments on a day-to-day basis. Herrnstein, Blough, Anger and others started doing experiments that did not have Skinner's daily input, and by 1960 he had only sporadic involvement in individual experiments. Skinner worked like a physiologist, but the sequencing of experimentation was not like most mainstream physiology. Typically, physiology starts with many acute experiments on reversible phenomena. When these experiments give a general understanding of the functional organization of the system, chronic experiments over weeks would be started. Physiological changes in long term experiments lead to effects that are not always reversible. In contrast, most of Skinner's work on schedules started as chronic experiments. The subject was studied daily until a steady state was achieved. A change in schedule led to a rapid change in behavior and, to a first approximation, the steady state under the new schedule was not dependent on what had gone before. It was the large element of reversibility that permitted the Pigeon Laboratory experiments to be conducted the way they were. Successive changes were made in the schedules of individual subjects and their effects were assessed. Different subjects were changed in different ways. If details of the successive changes had been important in determining steady state responding, the Pigeon Laboratory way of proceeding would have led to an uninterpretable chaos of inconsistent results. The purpose of the work reported in Schedules of Reinforcement (1957) was to survey the field. Ferster knew what they were doing. "We are skimming the cream," he said, "Others will have to come along and make our findings definitive." If the daily work in the Pigeon Laboratory was not like mainstream physiology, it was even less like mainstream psychology. Skinner had no hypothesis, no prior design to the experiments and no statistics after them. Ferster and Skinner discussed the possibility of dedicating Schedules of Reinforcement to "all those designers of experiments and statisticians with whose help this work would never have been done." Skinner also worked hard at his writing. It appeared that he always thought that being a great scientist was second best to being a great writer, but he certainly thought being a great scientist was better than being less than a great writer. For the rest of his life he devoted a great deal of effort to writing, primarily to try to spread the message of the good that could come from a scientific analysis of behavior. It is too early to asses the impact of his writings. He certainly infuriated a large fraction of the psychological profession by his contemptuous disregard of their shibboleths and a considerable fraction of the intellectual general public by his challenge to the applicability or reality of many of the dogmas of their humanistic education. While Skinner was in his prime, he overawed most psychologists who disliked what he stood for. His uncompromising science, his letting the chips fall where they may, silenced them but their resentment of Skinner persisted. It was increased by his disdain of their cherished theories. He regarded the theories as not even worth comment and worked as though they did not exist. That they half realized he was right made it all the more galling. But none could succeed him in that role to silence the enemies of a scientific analysis of behavior. Therefore there is a resurgence of "cognitive neuropsychology" and similar nonscientific counter attacks. The swing was predictable. Will the pendulum swing back or will
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it have to be pushed back with almost as much effort as the first time? Would it have been better for Skinner to have confined his attention to educating scientists and convincing more of them of the possibility of a scientific approach to behavior as he did, for example, in Science and Human Behavior (1953)? Should he have made scientists his only audience? Popularization necessitates oversimplification and it is Skinner's oversimplifications that have stocked his detractors' armory. If, 50 years from now, he is not regarded as one of the 2 or 3 greatest scientists of the 20th century something went wrong. Because he was.
Notes This symposium was presented at the Annual Meeting of the Pavlovian Society, Lord Baltimore Hotel, Baltimore, Maryland, September 27, 1991. Skinner's letter to Sannders, and the extract from Vargas, (1991) are quoted with permission of the B. E Skinner Foundation and Julie S. Vargas.
References Ferster, C. B., and Skinner, B. E (1957). Schedules of Reinforcement. New York: Appleton-Century-Crofts. National Public Radio. (1990). "All Things Considered." Interview with B. E Skinner, July 27th, 1990. Division 25 Recorder, 24/25, 34-36. Pavlov, I. E (1927). Conditioned Reflexes. New York: Oxford University Press. Skinner, B. F. (1938) Behavior of Organisn~. New York: D. Appleton-Century. Skinner, B. E (1945a). The operational analysis of psychological terms. Psychological Review, 42, 270-277. Skinner, B. E (1945b). Baby in a Box. Reprinted from Ladies Home Journal, October 1945, in Cumulative Record, 419-426. New York: Appleton-Century-Crofts. Skinner, B. E (1948). Walden Two. New York: Macmillan. Skinner, B. E (1953). Science and Human Behavior. New York: Macmillan. Skinner, B. E (1956). A case history in scientific method. American Psychologist, 11, 221-233. Skinner, B. E (1957). Verbal Behavior. New York: Appleton-Century-Crofts. Skinner, B. E (1981). Selection by consequencies. Science, 213, 501-504. Thorndike, E. L. (1898). Animal intelligence. Psychological Review, Monograph Supplement, volume 2, no. 4. Vargas, J. S. (1991). B. F. Skinner-the last few days. Journal of the Experimental Analysis of Behavior, 46, 105-112.
Boston University It is fitting that Skinner be honored by a society honoring Pavlov. Pavlov and Skinner each published a book of profound importance. Pavlov published Conditioned Reflexes in 1927 and only eleven years later, in 1938, Skinner published The Behavior of Organisms. Both books carried a number of similar original messages. Both Pavlov and Skinner treated psychology as an objective experimental natural science in which behavior was the datum. Both books were descriptions of the results of a long series of highly original experiments, the experimental problems being empirically derived, that is, based upon the results of prior experiments. Both placed their work in an evolutionary context, substituting Darwin's notion of continuity of mind with continuity of behavior, and making no fundamental distinction between man and other species. The most important similarity between the work of Pavlov and Skinner, a similarity that rarely receives comment, is that both reported experiments designed to demonstrate behavioral phenomena in the single animal. This requires great emphasis upon the details of the experiments themselves, with continual alteration and refinement of experimental procedures. Both eschewed group studies, statistics and formal hypothesis testing experimental designs. The major strength of this approach is that it leads to scientific discovery in a way that formal experimental design does not. In the hands of both Pavlov and Skinner new behavioral phenomena continually emerged as each worker progressed from experiment to experiment, investigating at many stages what were frequently unexpected findings (Skinner, 1956). The Behavior of Organisms was highly original in the historical context in which it appeared, and the approach and content of the book received considerable hostile comment. The difficulty of getting editors to accept papers on operant conditioning ultimately led, in 1957, to the founding of The Journal of Experimental Analysis of Behavior by Skinner and his associates. Skinner was a great admirer of Pavlov as shown by the 44 references he made to Pavlov in The Behavior of Organisms. Pavlov, in Conditioned Reflexes, approved of Thorndyke's (sic) The Animal Intelligence (1898) as the starting point of the experimental study of behavior, and he saw the American "Behaviorists" as the only representatives of the objective approach in psychology. Had Skinner been active at this time, I am sure Pavlov would also have quoted him with approval.
Address correspondence to: J. M. Harrison, Department of Psychology, Boston University, 64 Cummington Street, Boston, MA 02215. Integrative Physiological and Behavioral Science, July-September, 1992, Vol. 27, No. 3, 258-266
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Burrhus Frederick Skinner J. V. BRAD~"
Johns Hopkins School of Medicine When I was a graduate student I presented a paper at a psychological meeting which Skinner attended. At the conclusion of the session, Skinner congratulated me on the work and invited me to lunch. Since then I have worked on the experimental analysis of behavior. Fred Skinner was born on March 20th, 1904, in Susquehanna, Pennsylvania. He was the first child of Grace Burrhus, a "bright and beautiful woman," and William Skinner who "read law" and, as a draftsman for the Erie Railroad, wrote a text on "Workman's Compensation Law." Fred Skinner lived in the house where he was born until he went to college, having graduated from the same high school from which his mother and father graduated. He developed strong literary and artistic interests at home and majored in English at Hamilton College, in Clinton, New York. He received a Bachelor's degree Phi Beta Kappa and an award for classical Greek. He also, with encouragement from Robert Frost, tried his hand at writing. He spent six months of bohemian living in Greenwich Village, and a summer in Paris which, at that time, was full of literary expatriots. He returned and entered Harvard to study psychology because he felt that he had nothing to say as a writer. He submitted a thesis on the concept of the reflex and received his Ph.D. in 1931 and then became a National Research Council Postdoctoral Fellow with W. J. Crozier and worked on the central nervous system in the General Physiology Department at Harvard Medical School. From his laboratory over the next five years he produced the data for his first major treatise, The Behavior of Organisms (1938), completed when he was little more than thirty years old. By 1936, Fred had married Yvonne Blue, an English major from the University of Chicago, and had moved to the University of Minnesota where he remained for the duration of the war. While there, he attempted, without success, to interest the war office in the use of pigeons to guide bombs to designated marine targets (Pigeons in a Pelican). When his second daughter Julie was born he constructed the famous "baby box" designed to mechanize early child care (Skinner, 1945b). While at Minnesota, he also started work on Walden Two (1948), his utopian strategy for community living. In 1945 he moved to Indiana where he became chairman of the Department of Psychology. Three years later, in 1948, he moved back to Harvard. He remained at Harvard, after briefly considering a move to the University of California at La Jolla in the 1960s, until his death in 1990. The early days in the physiology laboratory had stimulated Skinner's abiding interest in verbal interactions, which culminated in a major contribution about 25 years later. During this time he received two Guggenheim Fellowships, took a summer course at Columbia, and gave the William James lectures at Harvard, all of which became the book, Verbal Behavior (1957). This book produced a storm of protest led by the most prominent of the linguistic scholars. Skinner's response (quite typical) to an inquiry regarding the most influential of the critical reviews was that he had read the first few paragraphs, realized the reviewer had missed the point and put it aside to return to more useful pursuits. Skinner's major contribution concerned the conceptual analysis of behavior. He considered the problem of understanding behavior to revolve around the identification of a unit of analysis, and chose as the unifying theme, the lever press, which he developed in the Behavior of Organisms, his book that made a tremendous impact upon experimental psychol-
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ogy. The methods developed in this book are still used by both psychologists and neural scientists who study behavior. Skinner insisted on the study of behavior for its own sake, and believed that it was the relationship between behavior and the environment that had to be explained. He strongly objected to mentalistic explanations which sought to explain behavior by recourse to an unexplained mental apparatus or a conceptual nervous system. However, he realized that events occurred in the body, that the skin was not a barrier to the analysis of "private events," and that such events had to be analyzed in a complete system of psychology. In a volume published a year before his death, he addressed a broad range of topics including: Cognitive thought; the initiating self concept; rule governance; and genes and the evolution of social behavior. Skinner is most widely quoted for the extension and application of his ideas to human behavior. The same analytical strategies that characterized Skinner's work have been applied in clinical settings. This had a demystifying effect upon the domains of psychotherapeutie intervention. Further applications led to the development of teaching machines, programmed instruction, and community treatments for juveniles. The greatest impact has been upon the majority of the institutions for the mentally retarded, in which behavioral analytic principles have made a major contribution to the mental health management of these people. Skinner was a controversial figure throughout his career and he remained an alert, reflective and feisty scholar who gave no quarter when confronted by those who would threaten the intellectual integrity of his field. He fought leukemia while continuing to write and even lecture on rare occasions, and gave his final address at the 98th convention of the American Psychological Association when accepting a citation for Outstanding Lifetime Contributions. In the course of that lecture he aimed one last salvo at those who, in the absence of observable representations of reality, have resorted to "theories about what is going on in the head of the mind," labeling currently fashionable "cognitive science" as the "creationism of psychology" ! He sent the manuscript based on this lecture to the American Psychologist the evening before he died. The measure of the man is perhaps nowhere more clearly reflected than in the following excerpt from a letter Skinner sent to me when he was starting his leukemia treatment. So long as I get platelets and red cells I feel perfectly normal. But, of course, in the not too distant future, some silly infection will take me off. I've had a good life, and it would be rather ungracious to complain, don't you think?
Skinner's View of Organism CHARLESCATANIA
University of Maryland, Baltimore I was an undergraduate at Columbia where I also obtained an MA working with Schoenfeld and Keller. Keller was a close friend of Skinner, and it was natural that I should move to the old psychology department at Harvard to obtain a Ph.D. under Skinner. I maintained a continuous close connection with Skinner until his death. In Skinner's first book, The Behavior of Organisms (1938), his interest in biology is seen in his use of the word "organism" (after Loeb's "The organism as a whole"), as indicating animals in general, including man, to whom he thought his work on the rat was directly
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relevant. In Science and Human Behavior (1953), he strengthened his ties with biology, particularly with respect to Darwin's ideas of natural selection by the environment of the behavior of the species (phylogenie selection). Skinner visualized three modes of selection of behavior by the environment; Darwinian (phylogenic selection), ontogenic selection of the behavior of each individual due to the environmental consequences of the behavior, and cultural selection (Skinner, 1981). Natural selection refers to Darwin's account of evolution in terms of the differential survival and reproduction of the varied members of a population; the environment naturally selects certain behavioral (and other) variations over others, and these are passed on to subsequent generations. The mechanism of transmission is genetic and the source of variation is mutation. Skirmer's ontogenic selection operates over the lifetime of the individual animal, environmental consequences selecting, in this case, from behavioral variation in the individual. "In both operant conditioning and evolutionary selection of behavioral characteristics, consequences alter future behavior. Reflexes and other innate patterns of behavior evolve because they increase the chances of survival of the species. Operants grow strong because they are followed by important consequences in the life of the individual" (Skinner, 1953, p. 90). Through phylogenic mechanisms operating over generations, the behavior of a parent can survive in the behavior of its offspring. Through ontogenic mechanisms operating over the lifetime of a single organism, some types of behavior are more likely than others to survive in that organism's behavior. When the offspring can acquire behavior from the parent or from any other organism (e.g., through observation, imitation of verbal behavior), a third area for selection is created, cultural selection. Skinner's third variety of selection, cultural selection, occurs when behavior, particularly verbal behavior, is passed on from one individual to another. For example, what someone has written could survive that person's death if it is read by others. Such shared verbal behavior is part of the culture of the group. One significant consequence of Skinner's cultural selection, was that it led to the analysis of how scientific and other vocabularies are established and maintained. Such an analysis does not proceed in terms of grammatical or linguistic structures, but in terms of the antecedents and consequences of verbal behavior. It is frequently assumed that a major function of verbal behavior is to communicate feelings, thinking or emotions. This assumption is untenable because verbal communities can not create and maintain vocabularies based upon such events. However, we learn to talk of some private events from the same verbal community that teaches vocabularies dealing with public events. The teaching of such a vocabulary can be based only on what is mutually accessible to listener and speaker, that is, overt events correlated with the private event. Private and public events are assumed to have the same kind of physical dimensions. A parent can teach a child color names because both parent and child can see the colors, and the parent can correct the child's response. Likewise, a vocabulary of private events can be taught only from terms based upon events to which the verbal community has access. For example, a child may learn to use the word "pain" because the parents have access to the events which caused an injury and the child's crying or facial expression. Reports of private events can be no more reliable than the public events correlated with them. Some verbal responses may be determined, not by a private event, but by observation of one's own behavior. For example, the observation that one is eating voraciously may lead to the conclusion that one is hungry. Here, one is saying of one's self what would be said of another eating equally voraciously. These examples show that Skinner's analysis of private events (Skinner, 1945a) must apply to all psychological terms. Vocabularies of all kinds are not based on linguistic rules,
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for example, but upon the consequences of behaving verbally. The essential questions are, how could the words have been learned and how could they have been taught? Skinner was told he had leukemia after receiving a bone marrow test following an attack of angina. When given only two months to live he described his reactions in an interview on National Public Radio in 1990: I am not religious, so I don't worry about what will happen after I am dead. And when I was told that I had this and would be dead in a few months, I didn't have any emotion of any kind at all. Not a bit of panic, or fear, or anxiety. Nothing at all. The only thing that touched me was, and really, my eyes watered when I thought of this, I will have to tell my wife and daughters. You see, when you die you hurt people, if they love you. And you can't help it. You have got to do it. And that bothered me. But otherwise, my dying, I knew I was going to die. N o w I know about when. I've had a very good life. It would be very foolish of me to complain, in any way, about it. So I'm enjoying these last few months as well as I ever enjoyed life. Later in the interview, Skinner added the following: It's very curious, is leukemia. I recommend it as a terminal illness, because if you get blood then you're perfectly normal, except that the white cells deteriorate, and eventually you are extremely vulnerable to infection, and that's why my wife may have asked you to wash your hands or something, I don't know. It's silly because the doctor tells me probably what you will die of is something you already have in you, but it will suddenly have a field day and it'll be the end. Something like pneumonia or something. But until that last couple of days you are perfectly healthy. I first heard about Skinner's leukemia about a month after the radio interview. At that time I was corresponding with Skinner about a paper that appeared in the American Psychologist, and Skinner's letter (of Jan. 15th, 1990) included the following paragraph: The leukemia is something of a nuisance. I have to go over once a week or so for transfusions and whatnot and have recently had a vascular access catheter put in on my chest to avoid getting needles into large veins on each occasion. I am feeling fine and enjoying life, though I am not getting as much done as I once did. The following appeared in a later letter dated 10th Feb. 1990: The leukemia is under control in one sense; so long as I have transfusions of platelets and red cells, I feel perfectly normal. However, my white count is going way up and that means that my resistance is declining. Although I will feel fine up to the end, something or other will take me off in a hurry, so I am told. I've had a good life and this doesn't bother me too much. The last letter I received from Skinner was dated 12th July 1990 and included the following comment: "The critical episode in the leukemia a couple of weeks ago has put me back .... Wish I had time for more but that's that."
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Skinner accepted an award for a lifetime of achievement from the American Psychological Association on the 10th of August, 1990, and this was to be his last public appearance. He died on August 18th, 1990, while in the hospital. "Near the end, his mouth was dry. Upon receiving a drink of water he said his last word, 'marvelous' " (Vargas, 1991, p.2). A few days after Skinner's death I received transcripts of letters Skinner had written to A. P. Saunders, one of his Hamilton College professors, with the comment "Dear Charlie, Hope this amuses you. Fred" A letter to Saunders dated 16th August 1926, contains the following striking passage: Just before commencement (June 1) my grandfather Burrhus was operated upon by my friend the doctor for enlarged prostate. Two weeks later he was again operated on for hydrocele. Despite his age (77) he recovered rapidly and about the first of July came to our home to convalesce. While he was here I attended to all his dressings--which were numerous--and we got to know each other well. He was having some trouble with his s o n - - m y uncle--and he confided completely in me and gave me credit for straightening the affair out. He would let no one else do anything for him but me. After he was home here a week he took cold, went out of his head in a day or so and 3 days later died of bronchial pneumonia. For a day and a half I watched h i m - - h e was apparently awake yet unconscious save for neuralgic pains--he hiccoughed badly--until the last evening they gave him morphia. This depressed his lungs which brought on coughing and his right lung filled completely within an hour. Then all night long this organism--worn out, beyond repair lay there. Certain muscles of diaphragm went on functioning--a little air was pulled spasmodically into the remaining lung space. An overtaxed heart--sustained on strychnine--pumped impure blood--and gave out under the strain. His pulse weakened--he coughed a bit and lay still. I listened to his heart--it was still. I lifted him u p - - a little black fluid ran from his lips.
I watched this human organism wear out--watched it as unemotionally as possib l e - a n d tried to understand it. What had happened. The active idea which I had known as my grandfather was gone simply because certain physical properties of the body had given out. Was there anything more of him beside that, something spiritual? If so when did it leave him? At the last moment?--except for certain reflex muscular activities the minute before and the minute after were alike.
I am very sure that my grandfather--all of him--all that I knew of him and felt--his character, personality, emotions, skill, desires,--all--everything went as soon as the physical condition of his body became unfit for certain nervous coordinations. Just as the dreary character of the clock I now hear will vanish when the parts which give forth its ticking shall stop.
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Skinner at Work PETER D~ws
Harvard University Medical School In the 1950s Skinner was looking for someone interested in the behavioral investigation of pharmacological substances. I replied that I was and thereupon, in 1952 embarked on a new era in the behavioral investigation of drugs based on Skinner's ideas. After Skinner received his Ph.D. in psychology at Harvard, he stayed on as a Junior Fellow at the Society of Fellows. He was given space by Crozier in the Department of Biology. He also spent some time in the Department of Physiology at Harvard Medical School, where he probably knew Alexander Forbes, Hallowell Davis, Walter B. Cannon and Arturo Rosenbleuth. As the result of these early experiences, Skinner at work was more like a physiologist than a psychologist. He walked to work at Memorial Hall at the same time every morning. When he reached the Pigeon Laboratory in the basement, Charles Ferster would be waiting for him and they would go straight to work. Skinner believed in arranging the environment to help him do what he wanted to do. When in the laboratory he wanted to work, and made the ambience of the laboratory the discriminative stimuli for working. Any other activity would not be allowed. Different types of work were associated with different parts of the laboratory. When in the room where the pigeons worked, he was concerned with them, when in the workshop he was concerned with the design of some apparatus, and so on. If something else was to be discussed, then he would leave the room and talk in the corridor. The purpose of these arrangements was not to maximize work, but to maximize accomplishment at minimum effort. In the late 1920s and early 1930s, he worked long hours and weekends because that was the only way he could get results. He had no automated equipment, no Ferster, Morse, or Gollub to perform the routine chores of running experiments, and he had to make all the apparatus himself. He was fascinated by where his results were leading him, and impatient for more, and so worked all the time. All was different in the 1950s. He had resources to have as many experiments running in parallel as he wanted, automation had advanced and he had a Ferster or Morse to oversee the experiments, and Mrs. Papp to put the pigeons in the boxes. When he no longer needed to work all the time his working day usually ended by noon. The laboratory was in operation throughout a 24-hour day. The apparatus consisted of relays, timers, counters, and other devices mounted on black plastic panels equipped with fuse clips. The panels could be snapped onto the three or four rows of parallel brass rods that supplied the power, at 28 Volts DC or 110 Volts AC. Programming circuitry was made with snap leads interconnecting the timers, counters and other items. One or two cumulative records were connected to each apparatus. On a lower shelf stood the pigeon box: A Sears Roebuck aluminum picnic ice box. Inside, the partition that Sears provided to separate the ice block from the picnic materials was used to hold the key to peck, Christmas tree lights as visual stimuli and a Gerbands magazine to present grain as required: on the other side, the pigeon. The behavioral part of the apparatus was all original with the laboratory, and was constantly evolving. Pigeon keys were in large square mounts in 1953, but the rectangular keys with their wiping contacts appeared not many years later. The longest evolution occurred in the cumulative recorder. In 1950 recorders were large wooden boxes in which the pen was
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moved across the paper by friction on a string. Gerbrands, who worked in the psychology department machine shop, started manufacturing cumulative records and other apparatus in his garage. When that enterprise prospered he left Skinner to devote full time to his own company. Skinner was good at developing devices that worked, and then continuing to improve them. But it was characteristic of the atmosphere of the laboratory that n o b o d y - Skinner, Morse, Ferster or Gerbrands--claimed credit for any particular advance. As the decade of the '50s progressed there was a steady erosion of Skinner's personal involvement in individual experiments on a day-to-day basis. Herrnstein, Blough, Anger and others started doing experiments that did not have Skinner's daily input, and by 1960 he had only sporadic involvement in individual experiments. Skinner worked like a physiologist, but the sequencing of experimentation was not like most mainstream physiology. Typically, physiology starts with many acute experiments on reversible phenomena. When these experiments give a general understanding of the functional organization of the system, chronic experiments over weeks would be started. Physiological changes in long term experiments lead to effects that are not always reversible. In contrast, most of Skinner's work on schedules started as chronic experiments. The subject was studied daily until a steady state was achieved. A change in schedule led to a rapid change in behavior and, to a first approximation, the steady state under the new schedule was not dependent on what had gone before. It was the large element of reversibility that permitted the Pigeon Laboratory experiments to be conducted the way they were. Successive changes were made in the schedules of individual subjects and their effects were assessed. Different subjects were changed in different ways. If details of the successive changes had been important in determining steady state responding, the Pigeon Laboratory way of proceeding would have led to an uninterpretable chaos of inconsistent results. The purpose of the work reported in Schedules of Reinforcement (1957) was to survey the field. Ferster knew what they were doing. "We are skimming the cream," he said, "Others will have to come along and make our findings definitive." If the daily work in the Pigeon Laboratory was not like mainstream physiology, it was even less like mainstream psychology. Skinner had no hypothesis, no prior design to the experiments and no statistics after them. Ferster and Skinner discussed the possibility of dedicating Schedules of Reinforcement to "all those designers of experiments and statisticians with whose help this work would never have been done." Skinner also worked hard at his writing. It appeared that he always thought that being a great scientist was second best to being a great writer, but he certainly thought being a great scientist was better than being less than a great writer. For the rest of his life he devoted a great deal of effort to writing, primarily to try to spread the message of the good that could come from a scientific analysis of behavior. It is too early to asses the impact of his writings. He certainly infuriated a large fraction of the psychological profession by his contemptuous disregard of their shibboleths and a considerable fraction of the intellectual general public by his challenge to the applicability or reality of many of the dogmas of their humanistic education. While Skinner was in his prime, he overawed most psychologists who disliked what he stood for. His uncompromising science, his letting the chips fall where they may, silenced them but their resentment of Skinner persisted. It was increased by his disdain of their cherished theories. He regarded the theories as not even worth comment and worked as though they did not exist. That they half realized he was right made it all the more galling. But none could succeed him in that role to silence the enemies of a scientific analysis of behavior. Therefore there is a resurgence of "cognitive neuropsychology" and similar nonscientific counter attacks. The swing was predictable. Will the pendulum swing back or will
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it have to be pushed back with almost as much effort as the first time? Would it have been better for Skinner to have confined his attention to educating scientists and convincing more of them of the possibility of a scientific approach to behavior as he did, for example, in Science and Human Behavior (1953)? Should he have made scientists his only audience? Popularization necessitates oversimplification and it is Skinner's oversimplifications that have stocked his detractors' armory. If, 50 years from now, he is not regarded as one of the 2 or 3 greatest scientists of the 20th century something went wrong. Because he was.
Notes This symposium was presented at the Annual Meeting of the Pavlovian Society, Lord Baltimore Hotel, Baltimore, Maryland, September 27, 1991. Skinner's letter to Sannders, and the extract from Vargas, (1991) are quoted with permission of the B. E Skinner Foundation and Julie S. Vargas.
References Ferster, C. B., and Skinner, B. E (1957). Schedules of Reinforcement. New York: Appleton-Century-Crofts. National Public Radio. (1990). "All Things Considered." Interview with B. E Skinner, July 27th, 1990. Division 25 Recorder, 24/25, 34-36. Pavlov, I. E (1927). Conditioned Reflexes. New York: Oxford University Press. Skinner, B. F. (1938) Behavior of Organisn~. New York: D. Appleton-Century. Skinner, B. E (1945a). The operational analysis of psychological terms. Psychological Review, 42, 270-277. Skinner, B. E (1945b). Baby in a Box. Reprinted from Ladies Home Journal, October 1945, in Cumulative Record, 419-426. New York: Appleton-Century-Crofts. Skinner, B. E (1948). Walden Two. New York: Macmillan. Skinner, B. E (1953). Science and Human Behavior. New York: Macmillan. Skinner, B. E (1956). A case history in scientific method. American Psychologist, 11, 221-233. Skinner, B. E (1957). Verbal Behavior. New York: Appleton-Century-Crofts. Skinner, B. E (1981). Selection by consequencies. Science, 213, 501-504. Thorndike, E. L. (1898). Animal intelligence. Psychological Review, Monograph Supplement, volume 2, no. 4. Vargas, J. S. (1991). B. F. Skinner-the last few days. Journal of the Experimental Analysis of Behavior, 46, 105-112.
