The sports section of Monday's NYT had an article by two Wharton professors, Jonah Berger and Devin Pope, who found that NCAA basketball teams behind by a point at half-time won more than half of the time:
http://qbox.wharton.upenn.edu/documents/mktg/research/Losing_and_Winning.pdf
The connection to value competition: It's useful to have equal or 50-50 competition between parties (or control centers of the brain). Given that, a behavioral tendency for 49-51 to become 51-49 rather than 47-53 is useful.
(By itself, this "just-so", adaptationist point cuts little ice in favor of VC as a credible model; to do that, one would want to have a fairly sampled array of behavioral economic results that can be described as according or not with VC predictions.)
