“Power corrupts, but too much testosterone just makes you stupid.”

This astute comment followed a blog post by New Yorker writer Jon Lee Anderson on the still-unfolding sex-lies-and-email scandal involving former CIA director David Petraeus, his biographer Paula Broadwell, and a growing cast of supporting characters. The post set Petraeus’s fall against a backdrop of hero worship stoked by a desire to reimagine the Iraq War. OK, but let’s get back to that testosterone.

What psychologists and neuroscientists  who study power are finding is that it corrupts in part because of the surging testosterone that comes along with it—and the concomitant decline in the stress hormone cortisol. A little of this swirling hormonal cocktail can do wonders, but a lot can make people, well, stupid. In studies, the magnitude of the hormonal shift in folks given a sense of power corresponds with cognitive and behavioral changes that make them bolder and more charismatic, but also more reckless and less moral.

Before digging into this research, it’s worth saying that none of us is a slave to our hormonal ebb and flow. We make our choices, and we should own the consequences. But here is yet another powerful man brought low by a lack of power over himself. And once again the question arises: what’s with these guys? What is it about traditional power that’s so corrosive to willpower?