Diego Gambetta

 ( 21st-century Italian Social Scientists ) 

Gambetta has a long lasting interest in trust. In 1987, when the concept was largely ignored in the social sciences, he published a groundbreaking edited collection, with authors from all quarters of the social sciences ("Trust. Making and Breaking Cooperative Relations"). His subsequent work in this area, with the late economist Michael Bacharach, employs game theory to provide a rigorous definition of trust, and signalling theory to understand the nature of trust decisions. This work describes at once how trust can be threatened by "mimics" of signals of trustworthiness, and the general conditions under which signals of trustworthiness can be relied upon.Michael Spence, The Quarterly Journal of Economics, Vol. 87, No. 3 (Aug. 1973), pp. 355–374 1 Signalling theory, which emerged simultaneously in economics and biology in the early 1970s –asserts that the reliability of signals, in social interactions among humans and other animals, depends on whether the signals are supported by behaviour that would be too costly for (most) mimics to afford, while being affordable by genuine signallers.

After an imaginative application of the theory to how taxi drivers in dangerous cities decide whether to take on board hailers and callersGambetta, D., & Hamill, H. (2005). Streetwise. How taxi drivers establish their customers' trustworthiness. New York: Russel Sage on the basis of little information, his book Codes of the Underworld. How Criminals Communicate (published by Princeton University Press in 2009) applies signalling theory to analyse how credibility of communication is established in a world where trust is under multiple threats. Thomas Schelling, the Nobel Prize–winning economist, among the first and few to write on the economics of organised crime, wrote that the book "illuminates a vast field of strategic communication where trust cannot be taken for granted. There is nothing comparable in print, and the book's interpretations will carry well beyond the field of conventional crime." The book, listed by New Scientist as one of The best books of 2009, has been described by one reviewer as the product of a “brilliant economic naturalist.”

Gambetta's work has, in recent years, extended to examining violent extremists. A number of Gambetta's research questions have come from "puzzles", unexpected or counter-intuitive correlations, such as the presence of a large proportion of engineers among Islamic radicals. In 2005 he edited “Making Sense of Suicide Missions” (published by Oxford University Press), and he is now working with Steffen Hertog on a book on “Engineers of Jihad” for Princeton University Press.“Why are there so many Engineers among Islamic Radicals?” Archives Européennes de Sociologie, L (2), 201–230

In terms of direct intellectual influences on Gambetta's work, in addition to Thomas Schelling, one may count Michael Bacharach, Partha Dasgupta, Jon Elster and Bernard Williams.

2016. Engineers of Jihad. Princeton University Press

2009. Codes of the Underworld: How Criminals Communicate. Princeton University Press

2006 (editor). Making Sense of Suicide Missions. Oxford: Oxford University Press

2005. Streetwise. How Taxi Drivers Establish Customers’ Trustworthiness. New York: Russell Sage Foundation (with Heather Hamill)

1993. The Sicilian Mafia. The Business of Private Protection. Harvard University Press

1988a (editor). Trust. Making and Breaking Cooperative Relations. Oxford: Basil Blackwell

1987. Were they pushed or did they jump? Individual decision mechanisms in education. Cambridge: Cambridge University Press

2010. “Do strong family ties inhibit trust?”, Journal of Economic Behaviour and Organisation, 75, 3, 365–376 (with John Ermisch)

2009. “‘Heroic impatience’: the Baader-Meinhof Gang 1968–1977”, Areté, 29, 11–34 (published in the US in The Nation, 22 March 2010).

2006. “Trust’s odd ways”. In J. Elster, O. Gjelsvik, A. Hylland and K. Moene (eds.) Understanding Choice, Explaining Behaviour Essays in Honour of Ole-Jørgen Skog, Oslo: Unipub Forlag/Oslo Academic Press .

2005. “Deceptive mimicry in humans”. In S. Hurley and N. Chater (eds.), Perspective on Imitation: From Cognitive Neuroscience to Social Science, Cambridge: MIT Press, vol II, pp. 221–241.

2002. “Corruption: An Analytical Map”. In S. Kotkin and A. Sajo (eds.), Political Corruption of Transition: A Sceptic's Handbook, Budapest: Central European University Press, pp. 33–56 (2004 Reprinted in W. Jordan and E. Kreike (eds.), Corrupt histories. University of Rochester Press, pp. 3–28)

2001. “Trust as type identification”. In C. Castelfranchi and Yao-Hua Tan, Trust and Deception in Virtual Societies. Dordrecht: Kluwer Publishers, pp. 1–26 (with Michael Bacharach)

2001. “Trust in signs”. In K. Cook (ed.) Trust and Society, New York: Russell Sage Foundation, pp. 148–184 (with Michael Bacharach)

1998. “Claro!’ An essay on discursive machismo”. In J.Elster (ed.), Deliberative Democracy, Cambridge: Cambridge University Press, pp. 19–43 (2001. Spanish translation, in J.Elster (ed.) Democracia Deliberativa. Barcelona: Editorial Gedisa)

1998. “Concatenations of mechanisms”. In P.Hedstrοm and R. Swedberg (eds.), Social mechanisms. An analytical approach to social theory, Cambridge: Cambridge University Press, pp. 102–24

1995. “Conspiracy among the many: the mafia in legitimate industries” (with Peter Reuter). In G.Fiorentini & S.Peltzman (eds.), The economics of organised crime, Cambridge: Cambridge University Press, pp. 116–136 (2000).

1994. “Inscrutable markets”, Rationality and Society, 6, 3, 353–368

1994. “Godfather's gossip”, Archives Européennes de Sociologie, XXXV, 2, 199–223

1991. “In the beginning was the Word: the symbols of the mafia” Archives Européennes de Sociologie, XXXII, 1, 53–77

1988. “Fragments of an economic theory of the mafia”. Archives Européenes de Sociologie, XXIX, 1, 127–145

• Diego Gambetta at Nuffield College, University of Oxford