Women are hardwired to experience and recall emotions more readily than men, according to a study announced last month in the Proceedings of the National Academy of Sciences, as well as on CNN's morning show. "The wiring of emotional experience and the coding of that experience into memory is much more tightly integrated in women than in men," according to the study's lead author, psychologist Turhan Canli of the State University of New York at Stony Brook.
Perhaps because this statement -- dressed in the language of neuroscience -- confirms long-standing stereotypes about men and women, it was greeted by the press with little skepticism. None of the stories I've seen -- mostly reprints of an Associated Press report -- questioned the basis for Canli's unequivocal declaration of cognitive sexual difference. But it seems rather shaky to me. Canli and his co-authors tested 12 men and 12 women. (I suppose they were "average" men and women who accurately represent the rest of us.) Each subject was presented with pictures of mundane objects, such as bookcases and fireplugs, and of objects expected to evoke strong emotions, such as guns, gravestones, corpses and electric chairs. The subjects were then asked to grade the pictures for emotional intensity. Three weeks later, they were brought back into the lab and asked to recall which pictures they had rated as "extremely emotionally intense." Women reportedly had about a 15 percent higher recall rate. "For pictures that were highly emotional, men recalled around 60 percent and women were about 75 percent," according to Canli.
Canli also reported that in brain scans taken while the subjects viewed pictures, "experience and memory is processed in the same location" in women, but not in men. This is how Canli explained the MRI evidence on CNN: "You are looking at a slice of brain tissue, and the red blobs on it indicate regions of activation that are associated with the emotional experience or with the emotional memory. When you look at the women, it's in the same place. ... When you look at the men, the experience is on the left and the memory is on the right."
I'm no expert on magnetic resonance imaging, but I've read that it's open to interpretation. And somehow I find these red blobs unconvincing as evidence that women are more emotionally retentive than men. You don't have to be a scientist to wonder whether a study suggesting that the emotional memories of 12 women were up to 15 percent more accurate than the emotional memories of 12 men is proof that men and women think differently; you merely need a knowledge of history. Scientific studies "proving" that men are smarter or more analytical and less emotional than women, or that men and women use their brains differently, are periodically trumpeted and more quietly debunked. Consider the conviction of 19th-century scientists, who posited that men were smarter than women because their brains were heavier. In 1880, former U.S. Surgeon General William Hammond asserted that "the brain of a woman is inferior in at least 19 different ways to the brain of a man."
How did he know? Scientists hadn't studied the brains of women, as one of my favorite feminists, Helen Hamilton Gardener, pointed out. They were preoccupied with weighing the brains of famous men. Gardener skewered "scientific" theories about male and female brains in her 1893 book Facts and Fictions of Life. Lord Byron's reportedly huge brain weighed 2,238 grams, she acknowledged. But no man's brain weighed nearly as much as the 7,000 gram brain of a large whale. If scientists were right about the connection between brain weight and intelligence, Gardener observed, "Almost any elephant is ... perhaps an entire medical faculty."
Scientific understanding of the human brain has surely advanced in the last century, but sex stereotypes still have the power to influence research, or at least the presentation of research findings. The press tends to exaggerate and over-generalize findings that suggest natural cognitive differences between the sexes, while downplaying findings that suggest cognitive similarities -- or variabilities having little apparent connection to sex. During the 1980s and 1990s, a spate of stories highlighted some questionable studies that claimed to show natural differences in male and female mathematical aptitude, and to demonstrate the effect of hormonal fluctuations on women's reasoning abilities. One researcher suggested that females take estrogen to improve their SAT scores.
The press paid particular attention to a 1995 study by Yale researchers Bennett and Sally Shaywitz, which purported to show differences in the ways in which men and women use their brains. The Shaywitz study involved 19 men and 19 women who were asked to perform four cognitive tasks involving language and visual-information processing. MRI results showed no differences in brain functions of males and females when performing three of the tasks. But while performing one task (involving rhyming), 11 of 19 women (or 58 percent) reportedly used different parts of their brains than all 19 men. In other words, 100 percent of women performing three tasks and 42 percent of women performing one task apparently used their brains just like men.
How were these findings characterized? "Men and Women Use Brain Differently, Study Discovers," a New York Times headline blared, although it could just as easily have said, "Men and Women Use Brain Similarly." Does sex play a role in cognition? Maybe, maybe not. The press and the public like certainty and affirmation of popular biases. But real science thrives on the capacity for doubt.