title:         A Tournament of Party Decision Rules
authors:       James Fowler, Michael Laver
entrydate:     2006-10-20 16:59:35
keywords:
abstract:      In the spirit of Axelrod’s famous series of tournaments for strategies in the repeat-play prisoner’s dilemma, we conducted a “tournament of party decision rules” in a dynamic agent-based spatial model of party competition. A call was issued for researchers to submit rules for selecting party positions in a two-dimensional policy space. Each submitted rule was pitted against all others in a suite of very long-running simulations in which all parties falling below a declared support threshold for two consecutive elections “died” and one new party was “born” each election at a random spatial location, using a rule randomly drawn from the set submitted. The policy-selection rule most successful at winning votes over the very long run was declared the “winner”. The most successful rule was identified unambiguously and combined a number of striking features. It satisficed rather than maximized in the short run; it was “parasitic” on choices made by other successful rules; and it was hard-wired not to attack other agents using the same rule, which it identified using a “secret handshake”. We followed up the tournament with a second suite of simulations in a more evolutionary setting in which the selection probability of a rule was a function of its “fitness”, measured in terms of the previous success of agents using the same rule. In this setting, the rule that won the original tournament pulled even further ahead of the competition. Treated as a discovery tool, tournament results raise a series of intriguing issues for those involved in the modeling of party competition.

http://polmeth.wustl.edu/retrieve.php?id=649

**********************************************************
             Political Methodology E-Mail List
        Editor: Karen Long Jusko <[log in to unmask]>
**********************************************************
        Send messages to [log in to unmask]
  To join the list, cancel your subscription, or modify
           your subscription settings visit:

          http://polmeth.wustl.edu/polmeth.php

**********************************************************