Chicken dilemma: Difference between revisions
typos, links
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{{Merge|Chicken dilemma|date=September 2018}}
One type of election scenario which is particularly fraught is when there is a majority split into two subfactions (below called A and B), competing against a united minority (below called C) that is bigger than either of the subfactions. This scenario has been called the "chicken dilemma" because in many election systems, the two majority subfactions are in a situation that resembles the classic "[[W:Chicken (game)|chicken]]" or "snowdrift" game (especially if voters are not sure which of the two subfactions is larger). That is, if we assume each faction has a single, coordinated strategy defined as "cooperate" (vote both candidates A and B above bottom) or "defect" (bullet vote, with only the favorite above bottom); and that each faction values its preferred choice at 10, its less-preferred choice at 8, and candidate C at 0, many voting systems lead to the following payoff matrix:
{| id="Payoff matrix" style="background:white; float: right; clear:right; text-align:center;" align=right cellspacing=0 cellpadding=8 width=225
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# Some voting systems, such as approval voting, ignore the problem. Perhaps the assumption here is that it will be impossible to organize a defection without prompting a retaliation, and thus that both sides will prefer to cooperate. ("Mutual assured destruction"?)
# Some voting systems, such as [[Majority Choice Approval]], try to exploit the fact that each faction is not a single coordinated entity, but a group of individual voters. The idea is that if a small number of voters defect, they should be ignored; hopefully, in that situation, majority cooperation will be a stable strategy.
# Other voting systems, such as [[ICT]], try to exploit the fact that in a real-world election, A and B are never perfectly balanced; one subfaction is always larger. In this case, a voting system can encourage the smaller group to cooperate by threatening to elect C (punishing both groups) if the smaller group defects. The criterion below is passed only by this kind of voting system.
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In the chicken dilemma scenario described in the premise of the Chicken Dilemma Criterion (CD), defined above, if B won, then the B voters would have successfully taken advantage of the A voters'
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Because CD is so simple, such a simple
simple
...maybe one that doesn't speak of numbers of voters in the factions?
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The A voters are the voters who vote A over everyone else. The B voters are
the voters who vote B over
who vote C over everyone else.
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