The Frontal Cortex

Here's another common question I get at my book talks:

"Is there a difference between the male and female brain when it comes to decision-making? Are women really more intuitive? Which sex is the better decider?"

While there are certainly relevant differences between the male and female brain - that wash of sex hormones in the womb can have significant effects - I think it's important to begin by emphasizing the profound irrelevance of gender in most experimental studies of decision-making.

Let's begin with that perdurable cliche about female intuition. My own hunch is that women got associated with intuition, emotionality and all those other "irrational" aspects of cognition simply because that was a way of demeaning the female brain. While neuroscientists now respect the processing powers of our emotions - they reflect all that computation taking place in the unconscious - this wasn't always the case. To say someone trusted their feelings was another way of saying they lacked the fortitude and intelligence to be rational. Here's Aristotle:

The female is softer in disposition, is more mischievous, less simple, more impulsive and more attentive to the nurture of the young...The fact is, the nature of man is the most rounded off and complete.

Kant elaborated on the "softness" of the female mind and associated abstract thought with men; women, in contrast, were good at dealing with the concrete and mundane. Stanley Hall, the influential American psychologist, wasn't much better (as quoted here):

She works by intuition and feeling; fear, anger, pity, love and most of the emotions have a wider range and greater intensity. If she abandons her natural naivete and takes up the burden of guiding and accounting for her life by consciousness, she is likely to lost more than she gains, according to the old saw that she who deliberates is lost.

Needless to say, Aristotle, Kant and Hall didn't cite evidence or experiments for the frailties of the female mind - they just assumed it as given. But, as I noted above, there is very little evidence that women are more "intuitive," whatever that means. In fact, several studies that directly compared the decision-making styles of men and women have found the exact opposite. Consider this 2001 study, recently summarized by Michael Lewis:

Back in 2001, MIT's Quarterly Journal of Economics published an intriguing paper called "Boys Will Be Boys: Gender, Overconfidence, and Common Stock Investment." The authors, Brad Barber and Terrance Odean, gained access to the trading activity in over 35,000 households, and used it to compare the habits of men and women. What they found, in a nutshell, is that men not only trade more often than women but do so from a false faith in their own financial judgment. Single men traded less sensibly than married men, and married men traded less sensibly than single women: the less the female presence, the less rational the approach to trading in the markets.

Take that Aristotle.

Of course, most of these studies are behavioral. What can neuroscience teach us? One of the few decision-making studies that's found a relevant difference between male and female brains comes from the work of Colin Camerer, at Cal-Tech, and Read Montague, at Baylor College of Medicine. The scientists play a simple economic exchange game called the trust game, and it goes like this: at the start of each of 10 rounds, an "investor" is given an imaginary stake of $20. They can keep it all, or "invest" some of it with a "trustee". Any money that gets invested is tripled, and the trustee then has the option of returning some portion of that amount back to the investor. For example, if the investor keeps $10 and invests $10, then the trustee has $30 to divide ($10 x 3). However, if the trustee decides to keep all the money there is nothing the investor can do about it. Since the trust game is typically played for 10 rounds, both players have a selfish incentive to trust each other.

While this simple game was being played, Camerer and Montague imaged the brains of the two players, allowing the scientists to detect the neural roots of fidelity and betrayal. What does this have to do with the gendered brain? Well, men and women tend to play the trust game pretty differently. Here's Camerer:

We found a surprising effect of gender. When men decide how much to trust or repay, an area called the "medial cingulate sulcus" is active. This is an area used to process potential reward, and calculate numbers. The male brains are just "doing the math" and turn off after they have made a decision. The female brains are quite different. After women have decided how much to repay, but before they know how their partner reacted to their decision, areas of the brain active in processing potential reward (ventromedial prefrontal cortex and ventral striatum) and in regulating worry and error-detection (caudate nucleus) are active. The women are worrying, and thinking about the reward consequences, after they have decided how much to repay.

My own guess is that future work on gender differences will find plenty of additional ways to distinguish the male and female brain. But these differences won't be reducible to trite, general truisms, such as "women are more intuitive" or "men are better at abstract thought". Instead, this research will focus on specific dispositions, such as the work by Camerer and Montague, which suggests that women tend to be a little more interested in parsing social interactions. When it comes to the brain, cliches are never true.