Epinets: The Epistemic Structure and Dynamics of Social Networks - Rilegato

Moldoveanu, Mihnea C.; Baum, Joel A. C.

Rilegato

ISBN 10: 0804777918 ISBN 13: 9780804777919

Casa editrice: Stanford Business Books, 2014

Riassunto

Epinets presents a new way to think about social networks, which focuses on the knowledge that underlies our social interactions. Guiding readers through the web of beliefs that networked individuals have about each other and probing into what others think, this book illuminates the deeper character and influence of relationships among social network participants.

Drawing on artificial intelligence, the philosophy of language, and epistemic game theory, Moldoveanu and Baum formulate a lexicon and array of conceptual tools that enable readers to explain, predict, and shape the fabric and behavior of social networks. With an innovative and strategically-minded look at the assumptions that enable and clog our networks, this book lays the groundwork for a leap forward in our understanding of human relations.

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Informazioni sugli autori

Mihnea C. Moldoveanu is Director of the Desautels Centre for Integrative Thinking at the Rotman School of Management, University of Toronto, where he is also the Associate Dean of the Full Time MBA Program. He is also the Founder, past CEO, and CTO of Redline Communications, Inc., a leading manufacturer of broadband wireless equipment for commercial and military communications. Joel A.C. Baum is the George E. Connell Chair in Organizations and Society and Associate Dean, Faculty at the Rotman School of Management, University of Toronto. He was a founding co-editor of Strategic Organization and served for over a decade as Editor-in-Chief of Advances in Strategic Management.

Mihnea C. Moldoveanu is Director of the Desautels Centre for Integrative Thinking at the Rotman School of Management, University of Toronto, where he is also the Associate Dean of the Full Time MBA Program. He is also the Founder, past CEO, and CTO of Redline Communications, Inc., a leading manufacturer of broadband wireless equipment for commercial and military communications.Joel A.C. Baum is the George E. Connell Chair in Organizations and Society and Associate Dean, Faculty at the Rotman School of Management, University of Toronto. He was a founding co-editor of Strategic Organization and served for over a decade as Editor-in-Chief of Advances in Strategic Management.

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EPINETS

The Epistemic Structure and Dynamics of Social Networks

By MIHNEA C. MOLDOVEANU, JOEL A.C. BAUM

Stanford University Press

Copyright © 2014 Board of Trustees of the Leland Stanford Junior University
All rights reserved.

ISBN: 978-0-8047-7791-9

Contents

Preface, vii, 
Chapter 1 Why We Need an Epistemic Model of Social Networks, 1, 
Chapter 2 An Epistemic Description Language for Social Interactions and Networks, 19, 
Chapter 3 "What Do You Think I Think You Think about It?": Epinets as a Tool for the Study of Network Structure, 51, 
Chapter 4 "I Think You Think I Think You're Lying": Trust, Secrecy, Covertness, and Authentication in Social Networks, 93, 
Chapter 5 "I Know You Think She Thinks I Trust You—But I Don't": Moves, Tactics, and Strategies Defined and Played in Epinets, 131, 
Chapter 6 "What You May Think We Think We Are Doing Here": By Way of Conclusion, 156, 
Glossary, 169, 
Notes, 173, 
References, 175, 
Index, 181, 

CHAPTER 1

Why We Need an Epistemic Model of Social Networks

Using examples and unstructured intuitions that highlight the importance of knowledge and of beliefs, both individual and mutual, to the outcomes of social situations and interpersonal relations, we argue for the usefulness of explicit epistemic models of human interactions and networks. We introduce the notions of an epistemic state—that is, a link between individuals and propositions they may know or believe—and of an epistemic tie—that is, a connection between individuals' epistemic states: if Alpha knows Beta knows Gamma knows that the park is closed after dark, then there is a set of epistemic ties connecting Alpha, Beta, Gamma, and the proposition that the park is closed after dark, which is part of the epistemic structure of the situation. We show how the structure of epistemic networks—epinets—formed by such links among individuals and their beliefs is relevant to the dynamics of human interactions, and how the dynamics of these networks are critical elements of complex interpersonal narratives.

* * *

What must human agents know about what other humans—with whom they are connected—know in order for the resulting patchwork of ties among them to function as a social network? Suppose that an anonymous survey of the friendship network of a seven-person executive team reveals that Beth, Harry, and Martha form a clique, with each describing the others as "friends." We designate the triad as a clique, rather than as a patchwork of ties, because we expect these three to exhibit some special forms of cohesion that may be evidenced by, for example, an above-average ability to coordinate, collaborate, communicate, and collude. In other words, we expect the triad to function as a clique: we expect each member to know—and know that the other two know—sensitive information about an event of mutual importance, or we expect that such sensitive information will quickly propagate within the triad.

What each knows of and about the others and their knowledge is the "epistemic glue" of the clique; it is what allows Beth to react to an unforeseen disaster in ways she knows Harry and Martha will find justifiable, and it is what allows her to make sense of their intentions based on observing their reactions and knowing what they think about what she knows. The grammar is somewhat complicated, but its complexity closely tracks that of the phenomena we expect a clique to exhibit. This epistemic superstructure is what makes the clique a clique—an identifiable network substructure with very specific expected properties—rather than a patchwork of ties and connections that can offer no further insight or predictive value.

At a more fundamental level, what must human agents know or believe about what others know or believe for their interactions to have joint or shared sense and meaning and to lead to stable patterns of interpersonal behavior? Game theory has contributed a basic canon of coordination, cooperation, and collaboration "games" that require coherent mutual beliefs (players' beliefs about other players' beliefs, about other players' beliefs about their own beliefs, and so on) whose "epistemic structures" can be analyzed to arrive at the preconditions for coordination, cooperation, collaboration, and even coherent communication. However, these neat analytical structures come at the cost of oversimplifying what humans believe and how they believe it as well as what they know and how they know it. States of knowing, like "oblivion" (not knowing and not knowing you do not know) or "forgetting" (knowing but not recalling what you know), are ruled out by assumptions such as those of "common priors" and "common knowledge," even though these states are all important to the unfolding of real human interactions. Moreover, because the event spaces of game theory do not admit interpretations and shadings, the resulting analyses lack the subtlety required to understand that humans interpret "Can I pray while I smoke?" very differently from the way they interpret "Can I smoke while I pray?" The conjunctive "while" functions very differently in first-order logic from the way it functions in plain English.

The contemporary importance of epistemic moves and games to an understanding of social interactions is clear from the direction of technological progress and innovation. Homo sapiens is Homo communicans and makes use of the full range of methods for passing information-bearing signals to shape, control, and predict the social milieu of being in the world. Consider the "cc" (carbon copy) and "bcc" (blind carbon copy) functions of everyday e-mail, which act as levers for shaping the informational structure of an interaction: "cc" creates pools of mutual knowledge about the contents of a message and serves as an aggregation tool; "bcc" oppositely brackets cliques that are "in the know" from individuals outside a circle of trust or power. But these are just the rudiments: new technologies allow senders to control a message after they have sent it—and possibly delete it—making it possible for them to deny ever having sent such a message even though they know the recipients know its contents; to "hack" into each other's e-mail servers to access a critical message without the message's author or recipient knowing that the hacker knows its contents; and to encrypt a message so that only intended recipients can decode it on the basis of access to the public or private key with which it has been encoded. The complexity of "interactive epistemology" has multiplied over the past few decades and continues to do so. A new language and new models are needed to understand the epistemic glue of human social interactions.

Although we are interested in building intuitive, yet precise, models of this epistemic glue, we are assuredly not pioneers of the epistemic dimension of social interactions. Nuanced treatments of epistemic structures and effects have appeared in the fields of artificial intelligence (Fagin et al. 1995), epistemic game theory (Aumann 1989), and analytic philosophy (Kripke 2011). Nor are we the first to point out that social networks (and social structures more generally) require descriptions sensitive to differences between what social agents think, and what we think social agents think, about such structures (Krackhardt 1987). What we are after is a tool kit for modeling, measuring, and manipulating the epistemic glue of human interactions and networks in ways that are as accessible to social network analysts as they are engaging to logicians, epistemic game theorists, and artificial intelligence researchers. We are building an application—an "app"—as much as we are theorizing, modeling, or philosophizing.

The Epistemic Structure of a "Friendship Tie"

Because we are building an app as much as a theory, we need to become intimate with "user requirements"—that is, the kinds of uses to which our modeling tool kit may be put. To that end, consider the friendship tie between Beth and Harry in our earlier example. Beth "knows" Harry: she sees him daily, is familiar with his latest setbacks and successes, works with him on a joint project, and sees him socially about every other week. That is her longhand unpacking of the shorthand answer "Harry is my friend," which she gave on the anonymous survey. Now what we want to know is this: when Beth needs Harry to convey to her, quickly and covertly, a sensitive piece of information she believes he has received from one of his acquaintances with whom Beth has no connection, what must Beth know about Harry for her to have good reason to believe that he will come through with it?

The minimal set of beliefs about Harry that Beth needs to rationalize her expectations may include the following: she believes that Harry knows the information is useful to her, that it is important to her that their office mate, Martha, does not know Beth has come to know it, and perhaps that Harry knows Beth will not divulge her source after he has passed along the information. Complications can arise: if Beth knows Harry's boss knows of Harry's ties to Beth and is monitoring Beth's actions to detect any sign that Harry has leaked to Beth the information he was entrusted to hold in confidence, then Beth may have to believe Harry knows of this threat and trusts in her integrity and competence not to "blow his cover." Alternatively, she may have to believe Harry does not know about this threat (in which case she may choose to inform him of it as befits the level of trust she assumes they share).

In each case, there is a structure to the knowledge that these social agents "share" that is both intelligible and intuitive, although it grows quickly in logical complexity with the addition of new information and people. The structure of this "epistemic glue" is rendered intuitive and intelligible by the recursive and interactive nature of what this "social knowledge," as it should properly be called, relates to, which is often knowledge about knowledge: Beth's knowledge about Harry's knowledge, which includes Harry's knowledge about Beth's knowledge about Harry's knowledge, and so on. The structure of the epistemic glue is "interactive": it links not only an agent's mind to a proposition but also one agent's mind to a proposition via another agent's mind: Beth knows Harry knows that his boss is monitoring Beth's actions for any sign of information leaked by Harry.

Of course, it is not only knowledge but beliefs, conjectures, and even barely articulated hunches that we want to capture and address with our language. Beth may not know—by any acceptable use of the term "knowing"—that Harry knows that the piece of information he possesses should be transmitted to her in a way that guards against eavesdropping—but she may simply believe it for reasons having to do with a complex of other prior beliefs. Harry may merely "sense" that Beth needs him to transmit the information covertly, without really having fully articulated that hunch as a proposition. All of these are legitimate objects of modeling, measurement, and manipulation for our app. We need a comprehensive conceptual framework to engage the range of states in which humans find themselves vis-à-vis propositions about the world. To study the gamut of mental objects playing pivotal roles in the relationships that form the fabric of human networks, we use the covering term epistemic states and represent these states as directed ties between social agents and propositions, which are grammatically correct sentences in natural language or well-formed formulas in propositional logic. And we use the term epistemic networks or epinets to refer to the networks that comprise a group of social agents, potentially true or possibly true propositions, and the interactive ("I think you think ...") and recursive ("I know I know ...") epistemic ties among them.

Let us give meaning to these words through usage. If Beth knows Harry knows that she needs him to convey a piece of sensitive information to her quickly and covertly, there is an epistemic sequence of ties connecting Beth to Harry to the fact that she needs him to act in such and such a way: as an agent to another agent to a proposition. If Harry knows that Beth knows this, then there is an epistemic tie sequence that connects Harry to Beth to Harry to the proposition in question; if Beth knows Harry knows she knows this, then there is a further epistemic tie sequence representing the correspondent connections; and so on. One can add agents (Martha, Harry's boss) and propositions (the boss's vigilance) to the epistemic network, as well as additional interactive epistemic ties involving one agent ("Beth knows that she knows what she knows"), two agents ("Beth knows Harry knows she knows ..."), or more ("Beth believes Harry believes that his boss believes that she believes ...").

Epinets in Shakespeare, Kesselring, and Durrenmatt. Epinets evolve and, as they do, "things happen," socially speaking. Far from being epiphenomenal—appearances sine consequences—changes in epistemic networks are those on which "the plots turn."

In Shakespeare's Othello (circa 1603; Ridley 1963), epinets representing the epistemic states of Othello, Desdemona, Iago, and the audience are essential to the interpretive schemata that allow the audience to understand and become involved in the play. The drama can be understood as the evolution of the epistemic states of its lead protagonist, Othello, from one of oblivion and trust through those of doubt and suspicion to one of certainty about a false belief regarding Desdemona's infidelity. The epistemic state changes can be traced to manipulations by Othello's lieutenant, Iago, that make careful use of the structure of interactive epistemic states—what Othello thinks Desdemona thinks when she says what she says; what he thinks she thinks he thinks; and so on).

At the beginning of the play, Othello believes unconditionally in Desdemona's loyalty and faithfulness. He trusts her, in the sense of believing that she could not evince fidelity and love if she did not have these feelings. Also, Othello is oblivious to the possibility that Desdemona is attracted to the young Cassio—one of his lieutenants and a rival to his chief lieutenant and schemer, Iago—in the sense that he gives this possibility no thought. It is not that, if asked about Desdemona's putative relationship with Cassio, he would say, "I do not know" or "I do not believe it is true"; rather, he would be shocked by Iago's presumption and by the suggestion of such a possibility. At the same time, Othello is jealous of Desdemona, yet not aware of his jealousy, and so is an easy target for Iago, who seeds doubt in Othello's mind regarding Desdemona's fidelity and manages to augment it by playing with what Othello thinks Desdemona thinks and with what Othello thinks Desdemona thinks he thinks: when Desdemona realizes that Othello is now both jealous and suspicious, she attempts to endear herself through loving entreaties. However, Iago has also managed to plant in Othello's mind that Desdemona is a master dissembler, and therefore Othello interprets these entreaties as masterful dissimulations of faithlessness rather than avowals of love.

Some outright lying and trickery are required of Iago to wean Othello from his trust of Desdemona, but his deceit succeeds because of his prior success in setting up the right epistemic states among Othello, Desdemona, Cassio, and himself. In particular, Othello believes Desdemona is unfaithful; he knows she does not know with whom he suspects her of being unfaithful; he believes she knows he is suspicious; and therefore he thinks she is likely to exaggeratedly "protest" her love for him, Othello, so as to lay his suspicions to rest. When Desdemona—oblivious to much of this epistemic structure—intervenes in favor of her presumed lover, Cassio (who has in the meantime fallen from Othello's grace after a contretemps into which he has been cunningly pulled by Iago), the epistemic trap Iago has set for Othello springs exactly as planned. Othello sees the situation as one of figuring out with whom his wife is cheating rather than whether or not she is cheating at all. Iago's soliloquies keep the audience informed of the dynamics of Othello's epistemic states, contributing to the indignation the audience feels as it witnesses the epistemically trapped Othello smother Desdemona in a fit of jealous rage— an indignation that is assuaged, though perhaps only partly, when a finally awakened Othello at last sees Iago for the vile manipulator he has become and attempts, unsuccessfully, to kill him.

In Joseph Kesselring's Arsenic and Old Lace (1942), Mortimer Brewster, the central character, is deciding whether or not to fulfill his promise to marry the woman he loves, within the complicated emotional landscape of his family, which includes two elderly spinsters, Abby and Martha—who, while passing as "good Christians," specialize in poisoning lonely old men with a home brew of elderberry wine laced with cyanide and arsenic; his brother Teddy, who believes he is Teddy Roosevelt and digs graves for the spinsters' victims in Mortimer's cellar thinking he is digging locks for the Panama Canal; and a murderous brother, Jonathan. The characters are oblivious to each others' beliefs and intentions—they do not know and do not know they do not know—and the only bits of information that are common knowledge are either false (the spinsters are good Christians) or relatively useless (Teddy thinks he is Roosevelt). It is this oblivion—of which the audience is aware—that creates the tension between what the characters say, do, and cause one another to think, and what the audience knows they know, as illustrated in Figure 1.1.

(Continues...)

Excerpted from EPINETS by MIHNEA C. MOLDOVEANU, JOEL A.C. BAUM. Copyright © 2014 Board of Trustees of the Leland Stanford Junior University. Excerpted by permission of Stanford University Press.
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Dettagli dell?edizione

• Editore: Stanford Business Books
• Data di pubblicazione: 2014
• Lingua: Inglese
• ISBN 10: 0804777918
• ISBN 13: 9780804777919
• Rilegatura: Copertina rigida
• Numero di pagine: 187
• Contatto del produttore: non disponibile
• Persona responsabile: non disponibile