Are humans completely rational in their decision-making? Research on testosterone suggests otherwise, and it’s not only men who are influenced by its fluctuations
I hate to break it to you, but if you are reading this and happen to be human, you’re subject to the vicissitudes of testosterone. The fact that your thoughts and behavior are even in the slightest way influenced by a hormone generated primarily by the gonads may challenge your most basic sense of self. But despair not, reader. Testosterone, or simply T, doesn’t necessarily reduce a person to base instincts and/or Hulk-like, destructive fits of rage. Researchers argue it can have a positive and useful place in our lives, particularly in the contexts of romance and work — or more generally, those areas of life where competition rules supreme.
Having said that, I should mention that our relationship with T begins long before we land our first job or even our first kiss. Indeed, it quietly starts shaping our lives while we’re still in the womb, and you can find traces of this early exposure carved into your hands; those of us exposed to higher levels of testosterone are more likely to have longer ring fingers than index fingers — the difference being especially pronounced in men. And while it’s not an exact science, this so-called 2D:4D digit ratio can predict a number of things about who we are as individuals — both physically and personality-wise.
When I spoke with Lee Gettler, the Director of Hormones, Health, and Human Behavior Lab at the University of Notre Dame, he confirmed that prenatal testosterone “can have modest impacts on neural development,” which may go on to influence a person’s behavior and cognition long after birth, but Gettler cautioned that the literature is “pretty mixed.”
However significant, these changes are what Jim Roney with the Department of Psychological and Brain Sciences at the University of California, Santa Barbara refers to as “organizational effects.” Being that they are developmental in nature, the effects of prenatal testosterone are essentially fixed, but over the course of a lifetime, T levels become much more fluid and its effects “temporary and reversible, like turning a switch on and off,” Roney tells me.
So, what flips on the switch?
If we learned anything from the most trending stories of the last couple of weeks, it is that the nature of courtship is inherently competitive and requires some serious legwork — whether you’re human or this adorable blue-capped cordon bleu finch. Might fluctuations in testosterone be to credit — or to blame — for all our grand romantic gestures?
Roney and Gettler have directed considerable energy to understanding our behavior and how it relates to changes in testosterone, specifically at various stages of a romantic partnership. For simplicity sake, I’ve carved them up into three rather self-explanatory, oversimplified blocks, and they are as follows: the chase, the catch, and parenthood.
Researchers have observed that during the so-called “chase,” single men generally have higher levels of testosterone when compared to their peers in committed relationships. Even after just brief encounters with young women, males experience a boost in T, says Roney. Why this might be may seem fairly obvious. Still, I turn the question over to Roney, who points to a number of studies in which short-term testosterone administrations reduce an individual’s fear response, and these changes, he explains, might promote certain types of risk-taking. That makes sense, as there’s certainly a large element of risk when pursuing the object of one’s affection. Anyone who’s experienced it knows full well that rejection’s rough.
Love at this stage can feel like a game and an incredibly competitive one at that, and the kind of myopic energy it requires isn’t necessarily very healthy over the long term. In terms of evolution, it has little function once a person has settled into a relationship. With that in mind, perhaps it comes as little surprise that once a male suitor finds himself in a monogamous partnership, his testosterone levels begin to drop. And according to Gettler, this change may bode well for the new couple.
“Men with lower testosterone,” Gettler tells me, “tend to be less prone to anger, better able to read others’ emotions, and are more empathetic — all qualities that would likely enhance their ability to engage in an emotionally supportive relationship.”
On the other hand, if these levels fail to peter out, trouble may be on the horizon. Roney points to a study that “found that testosterone in both partners negatively predicted relationship satisfaction.”
But what about partners who are satisfied with their relationship — or at least long enough to have a child?
“My prior longitudinal research on new fathers’ testosterone changes showed that the transition to fatherhood caused new dads’ testosterone to decline on average,” explains Gettler, adding that new fathers with lower testosterone “tend to be highly involved with caring for their children and are more sensitive to their cues.”
Gettler’s findings have been recently corroborated by a study led by the University of Michigan. Halfway through the experiment, participating fathers were asked to observe their one-year-old babies cry from behind a two-way mirror, and researchers found that compared to their T levels at the start of the study, fathers experienced a drop in testosterone upon seeing their children in distress. Interestingly, researchers also observed that these lower levels were associated with more positive parenting styles.
“We think that the decreases in testosterone in response to seeing your baby cry seems to help promote sensitive, nurturing care,” says Patty Kuo, the paper’s first author.
Feeling testy at work?
Are these fathers just as sensitive when relieved of their paternal duties? How about when it comes to their jobs?
John Coates of the University of Cambridge has conducted a number of studies on men in the context of work, specifically London traders, and his research suggests that there’s a strong link between higher testosterone levels and a person’s profitability on the trading floor. In other words, those who come to work with higher levels of T are more likely to go home a richer man.
In their 2007 paper published in the Proceedings of the National Academy of Science, Coates and his co-author Jane Herbert propose that elevated T levels may in part be driving a trader’s success because increases in the hormone correlate with “search persistence, appetite for risk, and fearlessness in the face of novelty.” But there are two sides of this coin, warns Coates, as fearlessness can lead to recklessness and ultimately, poor decision-making (video).
Either way, at the end of the day, a hormone exercises clear influence on economic markets, which is hardly a comforting thought.
As for female readers, who have thus far enjoyed learning that men, too, are subject to hormonal shifts, there’s more. A recent study out of the University of Michigan found that when placed in traditionally male roles, women also experience elevated levels of testosterone. Study participants were asked to act out firing someone, and in simply pretending to exercise this authority, their T levels rose, suggesting that higher levels in men are in part the result of socialization and not wholly biology. In other words, men are more likely to hold positions of power because they’ve been socialized into taking these roles and in wielding more authority, they experience higher levels of T. But women, too, exhibit elevated levels when given the same opportunity.
So, what’s the takeaway? Hopefully not that we’re all just a bunch of animals who can’t be held accountable for our thoughts and behavior. Instead, we are incredibly complex creatures making millions of decisions every day and not necessarily because of our biology, but sometimes, in spite of it.