Herbert A. Simon
|This article needs additional citations for verification. (January 2014)|
|Herbert A. Simon|
|Born||Herbert Alexander Simon
June 15, 1916
Milwaukee, Wisconsin, USA
|Died||February 9, 2001
Pittsburgh, Pennsylvania, USA
|Institutions||Carnegie Mellon University
University of California, Berkeley
Illinois Institute of Technology
|Alma mater||University of Chicago|
|Doctoral advisor||Henry Schultz|
|Other academic advisors||Rudolf Carnap
John R. Commons
|Doctoral students||Edward Feigenbaum
William F. Pounds
|Known for||Logic Theory Machine
General Problem Solver
|Notable awards||Turing Award 1975
Nobel Prize in Economics 1978
National Medal of Science 1986
von Neumann Theory Prize 1988
|Spouse||Dorothea Isabel Pye (1939-2001, his death) (1913-2002)|
|Children||Katherine, Peter, Barbara|
Herbert Alexander Simon (June 15, 1916 – February 9, 2001) was an American political scientist, economist, sociologist, psychologist, and professor—most notably at Carnegie Mellon University—whose research ranged across the fields of cognitive psychology, cognitive science, computer science, public administration, economics, management, philosophy of science, sociology, and political science. With almost a thousand very highly cited publications, he was one of the most influential social scientists of the twentieth century.
Simon was among the founding fathers of several of today's important scientific domains, including artificial intelligence, information processing, decision-making, problem-solving, attention economics, organization theory, complex systems, and computer simulation of scientific discovery.
He coined the terms bounded rationality and satisficing, and was the first to analyze the architecture of complexity and to propose a preferential attachment mechanism to explain power law distributions.
He also received many top-level honors later in life. These include: becoming a fellow of the American Academy of Arts and Sciences in 1959; election to the National Academy of Sciences in 1967; the ACM's Turing Award for making "basic contributions to artificial intelligence, the psychology of human cognition, and list processing" (1975); the Nobel Memorial Prize in Economics "for his pioneering research into the decision-making process within economic organizations" (1978); the National Medal of Science (1986); and the APA's Award for Outstanding Lifetime Contributions to Psychology (1993).
As a testament to his interdisciplinary approach, Simon was affiliated with such varied Carnegie Mellon departments as the School of Computer Science, Tepper School of Business, departments of Philosophy, Social and Decision Sciences, and Psychology. Simon received an honorary Doctor of Political science degree from University of Pavia in 1988 and an honorary Doctor of Laws (LL.D.) degree from Harvard University in 1990.
Early life and education
Herbert Alexander Simon was born in Milwaukee, Wisconsin on June 15, 1916. His father, Arthur Simon (1881–1948), was an electrical engineer who had come to the United States from Germany in 1903 after earning his engineering degree from the Technische Hochschule of Darmstadt. An inventor who was granted "several dozen patents", his father also was an independent patent attorney. Herbert's mother, Edna Marguerite Merkel, was an accomplished pianist whose ancestors had come from Prague and Cologne. Herbert's European ancestors had been piano makers, goldsmiths, and vintners. Simon's father was Jewish and his mother came from a family with Jewish, Lutheran, and Catholic backgrounds. Simon called himself an atheist.
Herbert Simon was educated as a child in the public school system in Milwaukee where he developed an interest in science. He found schoolwork to be interesting, but rather easy. Unlike many children, Simon was exposed to the idea that human behavior could be studied scientifically at a relatively young age due to the influence of his mother’s younger brother, Harold Merkel, who had studied economics at the University of Wisconsin–Madison under John R. Commons. Through his uncle’s books on economics and psychology, Simon discovered the social sciences. Among his earliest influences, Simon has cited Richard Ely’s economics textbook, Norman Angell’s The Great Illusion, and Henry George’s Progress and Poverty. In 1933, Simon entered the University of Chicago, and following those early influences, he studied the social sciences and mathematics. He was interested in biology, but chose not to study it because of his "color-blindness and awkwardness in the laboratory". He chose instead to focus on political science and economics. His most important mentor at the University was Henry Schultz who was an econometrician and mathematical economist. Simon received both his B.A. (1936) and his Ph.D. (1943) in political science, from the University of Chicago, where he studied under Harold Lasswell and Charles Edward Merriam.
After enrolling in a course on "Measuring Municipal Governments," Simon was invited to be a research assistant for Clarence Ridley, with whom he coauthored the book, Measuring Municipal Activities, in 1938, the same year that he and Dorothea married. Eventually his studies led him to the field of organizational decision-making, which would become the subject of his doctoral dissertation.
From 1939 to 1942, Simon acted as director of a research group at the University of California, Berkeley. When the grant to the group was exhausted, he joined the faculty of Illinois Institute of Technology, where he was a professor of political science from 1942 to 1949 and also served as department chairman. Back in Chicago, he began participating in the seminars held by the staff of the Cowles Commission who at that time included Trygve Haavelmo, Jacob Marschak, and Tjalling Koopmans. He thus began a more in-depth study of economics in the area of institutionalism. Marschak brought Simon in to assist in the study he was currently undertaking with Sam Schurr of the “prospective economic effects of atomic energy”.
In 1949, Simon became a professor of administration and chairman of the Department of Industrial Management at Carnegie Tech (later to become Carnegie Mellon University). He continued to teach in various departments at Carnegie Mellon, including psychology and computer science, until his death in 2001.
From 1950 to 1955, Simon studied mathematical economics and during this time, together with David Hawkins, discovered and proved the Hawkins–Simon theorem on the “conditions for the existence of positive solution vectors for input-output matrices." He also developed theorems on near-decomposability and aggregation. Having begun to apply these theorems to organizations, by 1954 Simon determined that the best way to study problem-solving was to simulate it with computer programs, which led to his interest in computer simulation of human cognition. Founded during the 1950s, he was among the first members of the Society for General Systems Research.
Simon had a keen interest in the arts. He was a friend of Robert Lepper and Richard Rappaport. Rappaport also painted Simon's commissioned portrait at Carnegie Mellon University.
In January 2001, Simon underwent surgery at UPMC Presbyterian to remove a cancerous tumor in his abdomen. Although the surgery was successful, Simon later succumbed to the complications that followed.
Study of decision-making
Administrative Behavior, from 1947, was based on Simon’s doctoral dissertation. It served as the foundation for his life's work. The centerpiece of this book is the behavioral and cognitive processes of making rational human choices, that is, decisions. By his definition, an operational administrative decision should be correct and efficient, and it must be practical to implement with a set of coordinated means.
Any such decision involves a choice selected from a number of alternatives, directed toward an organizational goal or subgoal. Realistic options were defined as having real consequences consisting of personnel actions or non-actions modified by environmental facts and values. In practice, some of the alternatives may be conscious or unconscious; some of the consequences may be unintended as well as intended; and some of the means and ends may be imperfectly differentiated, incompletely related, or poorly detailed.
The task of rational decision making is to select the alternative that results in the more preferred set of all the possible consequences. This task may be divided into three required steps:
- the identification and listing of all the alternatives;
- the determination of all the consequences resulting from each of the alternatives; and
- the comparison of the accuracy and efficiency of each of these sets of consequences.
Any given individual or organization attempting to implement this model in a real situation would be unable to comply with the three requirements. It is highly improbable that one could know all the alternatives, or all the consequences that follow each alternative.
The resulting question would be: given the inevitable limits on rational decision making, what other techniques or behavioral processes can a person or organization bring to bear to achieve approximately the best result? Simon writes:
The human being striving for rationality and restricted within the limits of his knowledge has developed some working procedures that partially overcome these difficulties. These procedures consist in assuming that he can isolate from the rest of the world a closed system containing a limited number of variables and a limited range of consequences.
Administrative Behavior, as a text, addresses a wide range of human behaviors, cognitive abilities, management techniques, personnel policies, training goals and procedures, specialized roles, criteria for evaluation of accuracy and efficiency, and all of the ramifications of communication processes. Simon is particularly interested in how these factors directly and indirectly influence the making of decisions.
Weaving in and out of the practical functioning of all of these organizational factors are two universal elements of human social behavior that Simon addresses in Chapter VII—The Role of Authority, and in Chapter X—Loyalties, and Organizational Identification.
Authority is a well studied, primary mark of organizational behavior, and is straightforwardly defined in the organizational context as the ability and right of an individual of higher rank to determine the decision of an individual of lower rank. The actions, attitudes, and relationships of the dominant and subordinate individuals constitute components of role behavior that may vary widely in form, style, and content, but do not vary in the expectation of obedience by the one of superior status, and willingness to obey from the subordinate.
Authority is highly influential on the formal structure of the organization, including patterns of communication, sanctions, and rewards, as well as on the establishment of goals, objectives, and values of the organization.
Decisions can be complex admixtures of facts and values. Information about facts, especially empirically-proven facts or facts derived from specialized experience, are more easily transmitted in the exercise of authority than are the expressions of values. Simon is primarily interested in seeking identification of the individual employee with the organizational goals and values. Following Lasswell, he states that “a person identifies himself with a group when, in making a decision, he evaluates the several alternatives of choice in terms of their consequences for the specified group”. A person may identify himself with any number of social, geographic, economic, racial, religious, familial, educational, gender, political, and sports groups. Indeed, the number and variety are unlimited. The fundamental problem for organizations is to recognize t personal and group identifications may either facilitate or obstruct correct decision making for the organization. A specific organization has to determine deliberately, and specify in appropriate detail and clear language, its own goals, objectives, means, ends, and values.
Chester Barnard pointed out that “the decisions that an individual makes as a member of an organization are quite distinct from his personal decisions”. Personal choices may be determined whether an individual joins a particular organization, and continue to be made in his or her extra–organizational private life. As a member of an organization, however, that individual makes decisions not in relationship to personal needs and results, but in an impersonal sense as part of the organizational intent, purpose, and effect. Organizational inducements, rewards, and sanctions are all designed to form, strengthen, and maintain this identification.
The correctness of administrative decisions is measured by two major criteria:
- adequacy of achieving the desired objective; and
- the efficiency with which the result was obtained. Many members of the organization may focus on adequacy, but the overall administrative management must pay particular attention to the efficiency with which the desired result was obtained.
Simon's contributions to research in the area of administrative decision-making have become increasingly mainstream in the business community thanks to the growth of management consulting.
Artificial intelligence and psychology
Simon was a pioneer in the field of artificial intelligence, creating with Allen Newell the Logic Theory Machine (1956) and the General Problem Solver (GPS) (1957) programs. GPS may possibly be the first method developed for separating problem solving strategy from information about particular problems. Both programs were developed using the Information Processing Language (IPL) (1956) developed by Newell, Cliff Shaw, and Simon. Donald Knuth mentions the development of list processing in IPL, with the linked list originally called "NSS memory" for its inventors. In 1957, Simon predicted that computer chess would surpass human chess abilities within "ten years" when, in reality, that transition took about forty years.
In the early 1960s psychologist Ulric Neisser asserted that while machines are capable of replicating 'cold cognition' behaviors such as reasoning, planning, perceiving, and deciding, they would never be able to replicate 'hot cognition' behaviors such as pain, pleasure, desire, and other emotions. Simon responded to Neisser's views in 1963 by writing a paper on emotional cognition, which he updated in 1967 and published in Psychological Review. Simon's work on emotional cognition was largely ignored by the artificial intelligence research community for several years, but subsequent work on emotions by Sloman and Picard helped refocus attention on Simon's paper and eventually, made it highly influential on the topic.
With Allen Newell, Simon developed a theory for the simulation of human problem solving behavior using production rules. The study of human problem solving required new kinds of human measurements and, with Anders Ericsson, Simon developed the experimental technique of verbal protocol analysis. Simon was interested in the role of knowledge in expertise. He said that to become an expert on a topic required about ten years of experience and he and colleagues estimated that expertise was the result of learning roughly 50,000 chunks of information. A chess expert was said to have learned about 50,000 chunks or chess position patterns.
Simon also was interested in how humans learn and, with Edward Feigenbaum, he developed the EPAM (Elementary Perceiver and Memorizer) theory, one of the first theories of learning to be implemented as a computer program. EPAM was able to explain a large number of phenomena in the field of verbal learning. Later versions of the model were applied to concept formation and the acquisition of expertise. With Fernand Gobet, he has expanded the EPAM theory into the CHREST computational model. The theory explains how simple chunks of information form the building blocks of schemata, which are more complex structures. CHREST has been used predominantly, to simulate aspects of chess expertise.
He was awarded the ACM A.M. Turing Award along with Allen Newell in 1975. "In joint scientific efforts extending over twenty years, initially in collaboration with J. C. (Cliff) Shaw at the RAND Corporation, and subsequentially [sic] with numerous faculty and student colleagues at Carnegie Mellon University, they have made basic contributions to artificial intelligence, the psychology of human cognition, and list processing."
Sociology and economics
Herbert Simon has been credited for revolutionary changes in microeconomics. He is responsible for the concept of organizational decision-making as it is known today. He also was the first to discuss this concept in terms of uncertainty; i.e. it is impossible to have perfect and complete information at any given time to make a decision. While this notion was not entirely new, Simon is best known for its origination. It was in this area that he was awarded the Nobel Prize in 1978.
At the Cowles Commission, Simon’s main goal was to link economic theory to mathematics and statistics. His main contributions were to the fields of general equilibrium and econometrics. He was greatly influenced by the marginalist debate that began in the 1930s. The popular work of the time argued that it was not apparent empirically that entrepreneurs needed to follow the marginalist principles of profit-maximization/cost-minimization in running organizations. The argument went on to note that profit-maximization was not accomplished, in part, because of the lack of complete information. In decision-making, Simon believed that agents face uncertainty about the future and costs in acquiring information in the present. These factors limit the extent to which agents may make a fully rational decision, thus they possess only “bounded rationality” and must make decisions by “satisficing,” or choosing that which might not be optimal, but which will make them happy enough.
Simon was known for his research on industrial organization. He determined that the internal organization of firms and the external business decisions thereof, did not conform to the Neoclassical theories of “rational” decision-making. Simon wrote many articles on the topic over the course of his life mainly focusing on the issue of decision-making within the behavior of what he termed “bounded rationality”. “Rational behavior, in economics, means that individuals maximize their utility function under the constraints they face (e.g., their budget constraint, limited choices, ...) in pursuit of their self-interest. This is reflected in the theory of subjective expected utility. The term, bounded rationality, is used to designate rational choice that takes into account the cognitive limitations of both knowledge and cognitive capacity. Bounded rationality is a central theme in behavioral economics. It is concerned with the ways in which the actual decision-making process influences decisions. Theories of bounded rationality relax one or more assumptions of standard expected utility theory”.[this quote needs a citation]
Simon determined that the best way to study these areas was through computer simulation modeling. As such, he developed an interest in computer science. Herbert Simon's main interests in computer science were in artificial intelligence, human-computer interaction, principles of the organization of humans and machines as information processing systems, the use of computers to study (by modeling) philosophical problems of the nature of intelligence and of epistemology, and the social implications of computer technology.
Some of Simon's economic research was directed toward understanding technological change in general and the information processing revolution in particular.
Simon's work has strongly influenced John Mighton, developer of a program that has achieved significant success in improving mathematics performance among elementary and high school students. Mighton cites a 2000 paper by Simon and two co-authors that counters arguments by French mathematics educator, Guy Brousseau, and others suggesting that excessive practice hampers children's understanding:
[The] criticism of practice (called 'drill and kill,' as if this phrase constituted empirical evaluation) is prominent in constructivist writings. Nothing flies more in the face of the last 20 years of research than the assertion that practice is bad. All evidence, from the laboratory and from extensive case studies of professionals, indicates that real competence only comes with extensive practice... In denying the critical role of practice one is denying children the very thing they need to achieve real competence. The instructional task is not to 'kill' motivation by demanding drill, but to find tasks that provide practice while at the same time sustaining interest.
— John R. Anderson, Lynne M. Reder, and Herbert A. Simon, 'Applications and misapplications
of cognitive psychology to mathematics education', Texas Educational Review 6 (2000)
In the 1972 book "What Computers Can't Do", the American philosopher Hubert Dreyfus criticized Simon for claiming that the computer programs of the day already exhibited intelligent behavior. Dreyfus also criticized Simon's optimism about the eventual success of AI as a result of a psychological theory of heuristics. This critique was partly based on the phenomenological claim that certain forms of intelligent human behavior can not be reduced to rule following. For a more detailed summary of the criticism, see Hubert Dreyfus's views on artificial intelligence.
For 63 years Simon was married to Dorothea and they had three children, Katherine, Peter, and Barbara. His wife died in 2002, during the year following his death in 2001.
- 1938 (with Clarence E. Ridley). Measuring Municipal Activities: a Survey of Suggested Criteria and Reporting Forms For Appraising Administration.
- 1943. Fiscal Aspects of Metropolitan Consolidation.
- 1945. The Technique of Municipal Administration, 2d ed.
- 1947. Administrative Behavior: A Study of Decision-Making Processes in Administrative Organization.
- – 4th ed. in 1997, The Free Press
- 1955. "A Behavioral Model of Rational Choice", Quarterly Journal of Economics, vol. 69, 99–188.
- 1956. "Reply: Surrogates for Uncertain Decision Problems", Office of Naval Research, January 1956.
- – Reprinted in 1982, In: H.A. Simon, Models of Bounded Rationality, Volume 1, Economic Analysis and Public Policy, Cambridge, Mass., MIT Press, 235–44.
- 1957. Models of Man. John Wiley. Presents mathematical models of human behaviour.
- 1958 (with James G. March and the collaboration of Harold Guetzkow). Organizations. New York: Wiley.
- 1958 (with Allen Newell and J. C. Shaw). Elements of a theory of human problem solving
- 1967. "Motivational and emotional controls of cognition", Psychological Review, vol. 74, 29–39, reprinted in Models of Thought Vol 1.
- 1969. The Sciences of the Artificial. MIT Press, Cambridge, Mass, 1st edition
- 1972 (with Allen Newell). Human Problem Solving.
- 1972. "Theories of Bounded Rationality," Chapter 8 in C. B. McGuire and R. Radner, eds., Decision and Organization, Amsterdam: North-Holland Publishing Company.
- 1977. Models of Discovery : and other topics in the methods of science. Dordrecht, Holland: Reidel.
- 1979. Models of Thought, Vols. 1 and 2. Yale University Press. His papers on human information-processing and problem-solving.
- 1980 (with K. Anders Ericsson). "Verbal reports as data", Psychological Review, vol. 87, 215–251.
- 1982. Models of Bounded Rationality, Vols. 1 and 2. MIT Press. His papers on economics.
- 1983. Reason in Human Affairs, Stanford University Press. A readable 115pp. book on human decision-making and information processing, based on lectures he gave at Stanford in 1982. A popular presentation of his technical work.
- 1987 (with P. Langley, G. Bradshaw, and J. Zytkow). Scientific Discovery: computational explorations of the creative processes. MIT Press.
- 1991. Models of My Life. Basic Books, Sloan Foundation Series. His autobiography.
- 1995 (with Peter C.-H. Cheng). "Scientific discovery and creative reasoning with diagrams", in S. M. Smith, T. B. Ward & R. A. Finke (Eds.), The Creative Cognition Approach (pp. 205–228). Cambridge, MA: MIT Press.
- 1996. The Sciences of the Artificial, 3rd ed. MIT Press.
- 1997. An Empirically Based Microeconomics. Cambridge University Press. A compact and readable summary of his criticisms of conventional "axiomatic" microeconomics, based on a lecture series.
- 1997. Models of Bounded Rationality, Vol. 3. MIT Press. His papers on economics since the publication of Vols. 1 and 2 in 1982. The papers grouped under the category "The Structure of Complex Systems"– dealing with issues such as causal ordering, decomposability, aggregation of variables, model abstraction– are of general interest in systems modelling, not just in economics.
- 1998 (with John R. Anderson, Lynne M. Reder, K. Anders Ericsson, and Robert Glaser). "Radical Constructivism and Cognitive Psychology", Brookings Papers on Education Policy, no. 1, 227–278.
- 2000 (with John R. Anderson and Lynne M. Reder). "Applications and misapplications of cognitive psychology to mathematics education", Texas Education Review, vol. 1, no. 2, 29–49.
- Honorary degree, University of Pavia, 1988.
- Herbert Simon, "Autobiography", in Nobel Lectures, Economics 1969–1980, Editor Assar Lindbeck, World Scientific Publishing Co., Singapore, 1992.
- Forest, Joelle , "John R. Commons and Herbert A. Simon on the Concept of Rationality", Journal of Economic Issues Vol. XXXV, 3 (2001), pp. 591–605
- "Herbert Alexander Simon". AI Genealogy Project. Retrieved 2012-03-15.
- Simon, Herbert A. (1978). Assar Lindbeck, ed. Nobel Lectures, Economics 1969–1980. Singapore: World Scientific Publishing Co. Retrieved 22 May 2012.
- Simon, H. A., 1955, Biometrika 42, 425.
- National Academy of Sciences. Nas.nasonline.org. Retrieved on 2013-09-23.
- Simon 1991, p.3, 23
- Simon 1991 p. 20
- Simon 1991 p.3
- Hunter Crowther-Heyck (2005). Herbert A. Simon: The Bounds of Reason in Modern America. JHU Press. p. 22. ISBN 9780801880254. "His secular, scientific values came well before he was old enough to make such calculating career decisions. For example, while still in middle school, Simon wrote a letter to the editor of the Milwaukee Journal defending the civil liberties of atheists, and by high school he was "certain" that he was "religiously an atheist," a conviction that never wavered."
- Simon 1991 p. 39
- Simon 1991 p. 64
- Simon 1991 p. 136
- Archived June 26, 2006 at the Wayback Machine
- Details for Papers of Robert L. Lepper, 1920–1989.
- Simon 1976
- Simon 1976, p. 67
- Simon 1976, p. 82
- Simon 1976, pp. 123–153
- Simon 1976, pp. 198–216
- Lasswell 1935, pp. 29–51 cited by Simon 1976, pp. 205
- Simon 1976, p. 205
- Barnard 1938, p. 77 cited by Simon 1976, pp. 202–203
- Volume 1 of The Art of Computer Programming
- Computer Chess: The Drosophila of AI October 30, 2002
- Herbert A. Simon, A Theory of Emotional Behavior. Carnegie Mellon University Complex Information Processing (CIP) Working Paper #55, June 1, 1963.
- Herbert A. Simon, Motivational and Emotional Controls of Cognition. Psychological Review, 1967, Vol. 74, No. 1, 29-39.
- Allen Newell and Herbert A. Simon, Human Problem Solving, 1972
- K. A. Ericsson and H. A. Simon, Protocol Analysis: Verbal Reports as Data, 1993
- Chase and Simon. Perception in Chess. Cognitive Psychology Volume 4, 1973
- Feigenbaum, E. A., & Simon, H. A. (1984). EPAM-like models of recognition and learning. Cognitive Science, 8, 305–336
- Gobet, F. & Simon, H. A. (2000). Five seconds or sixty? Presentation time in expert memory. Cognitive Science, 24, 651–682.
- "Press Release: STUDIES OF DECISION-MAKING LEAD TO PRIZE IN ECONOMICS". Nobelprize.org. 16 October 1978. Retrieved 11 May 2014.
- "John Mighton: The Ubiquitous Bell Curve", in Big Ideas on TVOntario, broadcast 1:30 a.m., 6 November 2010.
- Newell, A.; Shaw, J. C.; Simon, H. A. (1958). "Elements of a Theory of Human Problem Solving". Psychological Review (American Psychological Association) 65 (3): 151–166. doi:10.1037/h0048495.
- Barnard, C.I. (1938), The Functions of the Executive, Cambridge: Harvard University Press
- Lasswell, H.D. (1935), World Politics and Personal Insecurity, New York: Whittlesey House
- Simon, Herbert (1976), Administrative Behavior (3rd ed.), New York: The Free Press
- Simon, Herbert (1991), Models of My Life, United States: Basic Books
- Simon, Herbert A. 'Organizations and markets', Journal of Economic Perspectives, vol. 5, no. 2 (1991), pp. 25–44.
- Courtois, P.J., 1977. Decomposability: queueing and computer system applications. New York: Academic Press. Courtois was influenced by the work of Simon and Albert Ando on hierarchical nearly-decomposable systems in economic modelling as a criterion for computer systems design, and in this book he presents the mathematical theory of these nearly-decomposable systems in more detail than Simon and Ando do in their original papers.
|Wikiquote has quotations related to: Herbert A. Simon|
- Herbert Alexander Simon at the Mathematics Genealogy Project
- Herbert Alexander Simon at the AI Genealogy Project.
- A Tribute to Herbert A. Simon
- Full-text digital archive of Herbert Simon papers
- Mind Models online Artificial Intelligence exhibit
- pioneering research into the decision-making process within economic organizations
- History of Twentieth-Century Philosophy of Science BOOK VIII: Herbert Simon, Paul Thagard and Others on Discovery Systems – with free downloads for public use.
- — (12 December 1962). "The Architecture of Complexity" (PDF). American Philosophical Society 106 (6): 467–482. JSTOR 985254.
- "Herbert Alexander Simon (1901–1985)". The Concise Encyclopedia of Economics. Library of Economics and Liberty (2nd ed.) (Liberty Fund). 2008.