The dark side of online deals, why cockiness is advantageous and more in this week's news

Have I got a deal for you
Daily deal sites such as Groupon and LivingSocial boost sales and revenue for participating merchants, but the reputations of the businesses may take a hit. Reviews on Yelp that refer to daily deals are more negative, lowering merchant ratings for months after a daily deal offer, an analysis of more than 56,000 Groupon reviews reveals. The new work, reported by Boston University and Harvard researchers September 7 on, suggests that the ultimate economic effects of daily deals for the merchant aren’t clear. —Rachel Ehrenberg

The bright side of overconfidence
Unrealistic beliefs in one’s ability to win out over others have an upside. Overconfidence boosts individual success in competitive games, as long as desired objects provide big enough benefits to offset the costs of competing for them, say political scientists Dominic Johnson of the University of Edinburgh in Scotland and James Fowler of the University of California, San Diego. In computer models presented in the Sept. 15 Nature, Johnson and Fowler find that overconfidence spreads rapidly in populations because of its competitive advantages. Overconfidence greased the wheels of human cultural evolution, they propose, even if now it sometimes fosters financial collapses and wars. —Bruce Bower


Power of one in groups
Business teams may recruit and follow experts for good reason. Copying individuals known to have good judgment enables more accurate collective decisions, say zoologist Andrew King of the University of London and his colleagues. In groups consisting of people submitting guesses, one at a time, about the number of candies in a jar, individuals’ estimates and groups’ estimates — defined as quantities at the midpoint of all responses — came close to the right number if each guesser first saw the current best guess, the researchers report online September 14 in Biology Letters. Knowing the current best guess gave participants just enough guidance to restrain themselves from making huge overestimates, they suggest.  —Bruce Bower

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