News Notes for
Agent-Based Computational Economics (ACE)
September 1998

Prepared by:
Leigh Tesfatsion
Department of Economics
Iowa State University
Ames, Iowa 50011-1070

ACE Web Site Address:

Appended below are news items that may be of interest to researchers interested in agent-based computational economics (ACE), the computational study of economies modelled as evolving decentralized systems of autonomous interacting agents. Items of more permanent interest will be retained at the ACE Web site.
ACE news notes are anticipated about once every two months during the regular academic year (September-May) but may be distributed more or less often as warranted by the amount of news. Please contact Leigh Tesfatsion ( if you wish to be added or removed from this news list, or if you have any news items you wish to have included in the next ACE news notes. Please do **NOT** use the list address.
Thank you.

News Items

1. Chronicle of Higher Education Article

An article recently appeared in the Chronicle of Higher Education (July 24, 1998) entitled "Using Computer Models to Study the Complexities of Human Society." Various researchers (Rob Axtell, Steven Caldwell, John Casti, Noshir Contractor, Les Gasser, George Gumerman, Scott Page, Thomas Schelling, and Peyton Young) are questioned regarding what they perceive to be the advantages and disadvantages of using agent-based computer models to explore the functioning of both current and past human societies. The article can be accessed online at

2. Collective Dynamics of `Small-World' Networks

Note: The following news item is an abbreviated version of a letter to Nature by Duncan J. Watts and Steven H. Strogatz (Vol. 393, 4 June 1998). Correspondence and requests for materials should be addressed to D. J. Watts (

"Networks of coupled dynamical systems have been used to model biological oscillators, Josephson junction arrays, excitable media, neural networks, spatial games, genetic control networks, and many other self-organizing systems. Ordinarily, the connection topology is assumed to be either completely regular or completely random. But many biological, technological and social networks lie somewhere between these two extremes."

"Here we explore simple models of networks that can be tuned through this middle ground: regular networks `rewired' to introduce increasing amounts of disorder. We find that these systems can be highly clustered, like regular lattices, yet have small characteristic path lengths, like random graphs. We call them `small-world' networks by analalogy with the small-world phenomenon (popularly known as six degrees of separation)." [Note: John Guare's 1990 play and subsequent 1993 movie entitled "Six Degrees of Separation" popularized the idea that everyone in the world is connected to everyone else through a chain of at most six mutual acquaintances.]

"The neural network of the worm Caenorhabditis elegans, the power grid of the western United States, and the collaboration graph of film actors are shown to be small-world networks. Models of dynamical systems with small-world coupling display enhanced signal-propagation speed, computational power, and synchronizability. In particular, infectious diseases spread more easily in small-world networks than in regular lattices. ... Although small-world architecture has not received much attention, we suggest that it will probably turn out to be widespread in biological, social and man-made systems, often with important dynamical consequences."

3. Debate Between Stephen Jay Gould and Daniel C. Dennett:

An interesting debate between Stephen Jay Gould and Daniel Dennett was touched off by the publication by Dennett of Darwin's Dangerous Idea: Evolution and the Meaning of Life (Touchstone Books, 1996, ISBN: 068482471X). In Chapter 10 (Bully for Brontosaurus), Dennett begins an attack on the work of Gould with the following harsh assessment: "This chapter is about another myth -- Stephen Jay Gould, Refuter of Orthodox Darwinism. Over the years, Gould has mounted a series of attacks on aspects of contemporary neo-Darwinism, and although none of these attacks has proven to be more than a mild corrective to orthodoxy at best, their rhetorical impact on the outside world has been immense and distorting."

Gould responded with a two-part critique of Dennett's arguments (June 12 and June 26, 1997), which was followed by a response from Dennett and a further rebuttal by Gould (August 14, 1997). Further comments were then made by Steven Pinker followed by another rebuttal by Gould (October 9, 1997). All of these points and counterparts originally appeared on, and are now archived at, the New York Review of Books Web site at

4. Shopbots

Note: The following news item appeared in the UMBC AgentNews Webletter (Vol. 3, No. 1, May 16, 1998) by Timothy Finin (

"Shopbots seem to be gaining ground as a successful application of internet agent techniques. Excite recently purchased Jango and Yahoo is using technology developed by Junglee to provide shopbots for a variety of product categories. Other companies are offering services for single markets, such as books. Muenchhoff and Janz GmbH's Acses ( links into the databases of all its book sites, searching for your title. It returns the top selections, ranked by price, along with shipping and handling information, while linking to the respective Web sites. A recent Wired article discusses how shopbots may affect the book selling business."

Note: The Wired article in question is "Using Bots to Buy Books" by Jennifer Sullivan (May 14, 1998) and is available on-line at

Book Announcements

Note: The following book announcements have been incorporated into the syllabus of readings linked to the ACE Web site home page; links to publishers (for ordering purposes) can be found on the journals/publishers page linked to the ACE Web site home page.

Journal Announcements

Note: Pointers to any new journals listed below have been incorporated into the journals/publishers page linked to the ACE Web site home page.

Additional ACE-Related Web Sites

Note: Pointers to the following Web sites have been incorporated into the "other ACE-related Web sites" page linked to the ACE Web site home page.

Conference Information

Note: The following announcements have been incorporated into the conference page linked to the ACE Web site home page.

Miscellaneous Announcements

Reminder: Items Requested for ACE News Notes and Complexity

Just a reminder that if you have any ACE-related news items, or any information about ACE-related teaching materials, software, books, articles, journals, or conferences that you would like to have considered for inclusion in the ACE news notes, and/or the Complexity-at-Large section of the John Wiley journal Complexity, please email them to me (along with Web site information if available) at the following address:

Copyright 1998 Leigh Tesfatsion. All Rights Reserved.