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evolutionary biology of risk.
    First, the guys’ testosterone levels automatically shot up when the beautiful woman was watching.Having more testosterone flowing through their veins tends to inspire men to move faster and more recklessly.In fact, the boost in risk taking was found primarily among those fellows whose testosterone levels zoomed up the most.
    Second, the researchers gave the men a test tapping the functioning of the ventral medial prefrontal cortex, an area of the brain that cranks into high gear when we need to assess rewards and punishments.When the beautiful woman was watching, guys did worse on the test, suggesting that boosts in testosterone may have shut down this brain area, normally involved in making careful judgments.These findings make evolutionary sense to the extent that successfully showing off to a beautiful woman enhances a man’s chances of attracting her as a mate.To show off, though, a bloke needs to be willing to throw caution to the wind—to take his foot off the brakes and hit the gas—and take some otherwise foolish risks.
    The skateboarders didn’t consciously decide to take more risks when the woman was watching.Instead, unconscious ancestral mechanisms made this decision for them, by flooding their bodies with testosterone specifically when a woman could observe their behavior.
    Evolution has honed male biology to be attuned to reproductive opportunities, like the presence of an attractive woman.From the perspective of a fellow’s genes, though, it would be especially nice if, before he risked his neck, he could somehow ascertain that the woman watching him was currently capable of becoming pregnant.But is that even possible?
    In a laboratory at Florida State University, psychologists Saul Miller and Jon Maner investigated this precise possibility by observing men as they played a game of blackjack.In case you don’t hang out in casinos, blackjack is a card game in which you can choose to play it safe (by declining any new cards once you get to sixteen or higher) or to take risks (by deciding to take a new card and risk the possibility of “busting” by going over twenty-one).As the men played blackjack, the researchers had a young woman observe them.
    Just like the Aussie skateboarders, the Floridian fellows took more risks when the woman was watching.But this study raised the stakes.Over the course of the experiment, the researchers kept track of where the female research assistant was in her ovulatory cycle.Although she had been carefully instructed to dress and act identically every single day, her presence had a different effect on men’s play on the days she was ovulating.When she was most fertile, the fellows took the most risks.
    How did the men know she was ovulating?They didn’t, at least not in any way they could consciously identify.But their bodies knew.In a follow-up study, the researchers found that merely exposing men to the subtle scent of an ovulating woman’s T-shirt instantly caused men’s testosterone levels to shoot up.
    Armed with an understanding of the intimate connections between men’s risk-taking biology and reproductive success, let’s return to the saga of the Kennedys.The family’s penchant for risk occasionally led to bad judgments, unfortunate outcomes, and even a few dead Kennedys.Risk always involves trade-offs.Taking hazardous chances can lead to death, but it can also lead to payoffs like money and status.At a deeper level, though, the Kennedy men’s risk taking paid off in the most valuable currency in the evolutionary realm—reproductive success.Recall that women in all societies around the world are attracted to ambitiousmen willing to take risks to become successful.Although taking these kinds of risks led some of Joe Kennedy’s descendants to perish, his genes have flourished.In the course of only a few generations, the genes of this one Irishman have thrived—producing twenty-nine grandchildren and over sixty