If you've ever wondered why women do better than men at remembering their first date, last vacation, or a recent argument, researchers have an answer. A new study appearing in a journal published by the U.S. National Academy of Sciences suggests that emotional events leave a deeper trace in women's memory than men's.
State University of New York psychologist Turhan Canli often notices that his wife remembers emotional moments more vividly than he does. "I have that experience when I don't remember all that many things in my life, and I rely on my wife to help me out because she is the one that remembers a lot of details," he said.
Mr. Canli realizes that he is not alone; many of his male acquaintances share similar experiences. To explain these everyday observations, Mr. Canli and colleagues at Stanford University set out to study emotional memory of males and females in the laboratory.
Men and women in the experiment were shown nearly 100 images, ranging from neutral to highly emotional. Among the latter were pictures of corpses, gravestones, crying people, and even dirty toilets. The men and women were asked to evaluate the degree to which the images were positive or negative while the researchers recorded their brain activity. Three weeks later participants returned to the lab for a surprise memory test.
Professor Canli says the brain activity recordings showed that the women had more of their brain regions reacting to the emotional images and cataloging them into memory than the men.
"Even though everyone remembers emotional experiences better than neutral ones, women have an additional advantage to remember the emotional stimuli even better than do men," he said.
But these findings do not mean that men are less emotional than women. Another author of the study, Stanford neuropsychologist John Gabrielli says the picture might be more complex. "I think that what the results maybe show most directly is not that men are less emotional or have worse memories, but that somehow the connections in the brain between an emotion and memory are somehow less powerful," he said. "And this is slightly different than our everyday sense that men are simply less emotional, because in fact their brains respond quite powerfully to emotions. It's just they don't seem to incorporate that part of the brain into the part of the brain that makes memories for the future." The study poses yet another question: are women better at remembering emotional information because of genetic predisposition or because the culture expects them to do so?
National Institutes of Health neurologist Jordan Grafman says that if women indeed learn to remember emotional information, they might train their memory by describing to themselves whatever they experience. "It could be that women rehearse the emotional material they see more than men do, they put what they are seeing into words, in essence," he said.
But it is also possible that from birth the brains of women are wired to remember emotions more efficiently.
To see if nature, nurture, or both are responsible for the differences in emotional memory of men and women, Professor Canli and his team are planning to study how young boys and girls respond to emotional images. Additionally, Mr. Canli says that he and his colleagues will investigate whether women's sharp memory for emotional events might explain that they are two times more likely to experience depression compared to men.
"The downside of having a very effective mechanism that encodes emotional experiences into memory is that negative emotional memories persist longer or somehow play a more prominent role in one's mental life," he said. "If that were true, if it's a gender-based issue, then it could be a contributing factor toward mood disorders." Experts such as University of California neurobiologist Larry Cahill hope that the new study will help raise awareness that the brains of men and women are not operating identically. "At this point, the field is really trying to document what exactly are the differences between the brains of men and women," he said. "There is enough evidence that we can clearly say that we are on to something big here."
Experts say that future studies will aim at understanding what the differences in brain function imply for the mental and physical health of both sexes.