Charismatic Code, Social Norms, and the Emergence of Cooperation on the File-Swapping Networks

76 Pages Posted: 29 Oct 2002


In this paper Professor Strahilevitz addresses the question of why individual members of peer-to-peer file-swapping networks such as Napster, Gnutella, and Kazaa consciously choose to share their unlicensed copies of copyrighted content with anonymous strangers despite the absence of economic incentives for doing so. Rational choice theorists and many social psychologists ordinarily expect that in the absence of face-to-face contact or other communication, strangers who expect neither to engage in repeat-player interactions nor to be sanctioned for free-riding will be unlikely to contribute to a public good if such cooperation is somewhat costly. Yet Strahilevitz's study found that a majority of those users who downloaded songs from the MusicCity/Kazaa network shared at least some portions of their music collections with anonymous peers, despite an absence of face-to-face contact and a near absence of other user-to-user communication and repeat-player interactions. Previous research has suggested that many of these users do incur real costs in order to share their content. Strahilevitz attributes this cooperative behavior in part to the file-swapping networks' "charismatic code." Charismatic code is a technology that presents each member of a group with a distorted picture of his fellow group members by magnifying cooperative behavior and masking uncooperative behavior. Strahilevitz argues that users who are exposed to charismatic code and benefit from other users' contributions to these networks are likely to mimic the cooperative behavior they observe. The social norm of reciprocity can therefore engender surprisingly robust cooperation in environments that are characterized by fleeting interactions among anonymous individuals. Strahilevitz concludes that cooperative uploading is nevertheless the weak link in peer-to-peer file transfers, observing that strategies that magnify the prevalence of free-riding or otherwise diminish users' impulse to upload present attractive possibilities for curtailing copyright infringement on the Internet.

JEL Classification: K0, K4

Suggested Citation

Strahilevitz, Lior, Charismatic Code, Social Norms, and the Emergence of Cooperation on the File-Swapping Networks. U Chicago Law & Economics, Olin Working Paper No. 162, Available at SSRN: or

Lior Strahilevitz (Contact Author)

University of Chicago Law School ( email )

1111 E. 60th St.
Chicago, IL 60637
United States
773-834-8665 (Phone)
773-702-0730 (Fax)

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