In sumo wrestling, rankings are determined by the number of wins a wrestler achieves at bimonthly tournaments. In a 15-round tournament, wrestlers with a 7-7 record often win their final bout, which allows them to advance. There are theories that economic incentives may play a role, with higher-ranked wrestlers potentially being bribed to lose a fight to a competitor who would otherwise not advance. However, in the close-knit sumo community, there are also strong moral and social incentives for higher-ranked wrestlers to assist those at risk of falling back in the rankings.
Author Steven Levitt, working with journalist Stephen Dubner, shows how economic theories can be use...
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