Slate has an excellent article on why we have a tendency to root for the underdog. It’s a fascinating area because it involves the combination of our perception of fairness, our positive emotional reaction to winners and our biases about what sort of characteristics we think underdogs might have – all of which could be pulling us in different directions.
The article is packed full of relevant studies, but the idea that we consistently over-estimate the success of underdogs particularly caught my eye:
Researchers have found evidence for exactly this phenomenon‚Äîcalled the “favorite-long-shot bias”‚Äîat the horse track. One recent study [pdf] that compiled stats from some 6 million American horse races showed a steep drop-off in the return on winning bets, as the odds against those bets increased. In other words, bettors were throwing money at the underdogs and underbidding on the favorites. That’s not because we get some special pleasure from playing the ponies at 100-to-1, the authors argue. It’s because we tend to overestimate the long shots’ chances.
Full disclosure: I’m an occasional writer for Slate and I consistently over-rate the chances of long-shots.