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What Traders’ Testosterone Tells Us About Markets

June 11 (Bloomberg) -- An unusual study of traders’ spit may offer a taste of the future in how we understand what drives markets -- and why they aren’t as stable and efficient as we might hope.

Several years ago, two neuroscientists undertook an experiment on the trading floor of a major investment bank in London. Over eight consecutive business days, at both 11 a.m. and 4 p.m., John Coates and Joe Herbert took samples of saliva from the mouths of 17 traders. With these samples, taken before and after the bulk of the day’s trading activity, they measured the rising and falling levels of a number of steroid hormones, including testosterone, adrenaline and cortisol.