Women who take hormonal contraceptives such as birth control pills are better at remembering the main idea of an emotional event, while women not on contraceptives are better at retaining details, says a new study at the University of California, Irvine.
“What’s most exciting about this study is that it shows the use of hormonal contraception alters memory,” said UC Irvine graduate researcher Shawn Nielsen. “There are only a handful of studies examining the cognitive effects of the pill, and more than 100 million women use it worldwide.”
Nielsen added that the contraceptives do not damage memory. “It’s a change in the type of information they remember, not a deficit.”
The difference makes sense, said Nielsen, because contraceptives suppress sex hormones like progesterone and estrogen to prevent pregnancy. Those hormones have been linked to women’s strong “left brain” memory by the research group.
“This new finding may be surprising to some, but it’s a natural outgrowth of the research we’ve been doing on sex differences for 10 years,” said neurobiologist Larry Cahill.
For the study, groups of women — some taking contraceptives and the rest having natural hormonal cycles — viewed pictures of a mother, her son, and a car accident.
Some participants in each group were told the car had hit a curb, while others were told the car had hit the boy and had seriously injured him.
One week later, all participants took a surprise test requiring them to recall the information. Volunteers who were on hormonal contraceptives for as little as one month better remembered the main steps in the traumatic event — that there had been an accident, that the boy had been rushed to the hospital, that physicians worked to save his life and successfully reattached both his feet, for example.
Women not using contraceptives, however, recalled more details, such as a fire hydrant next to the car.
“Larry Cahill is already well known for his phenomenal research linking sex to memory,” said Pauline Maki, professor of psychiatry and psychology at the University of Illinois at Chicago, who specializes in memory and brain functioning. “The fact that women on oral contraceptives remembered different elements of a story tells us that estrogen has an influence on how women remember emotional events.”
Nielsen and researcher Nicole Ertman believe the findings could help answer why women experience post-traumatic stress syndrome more frequently than men, and how men recall events differently than women.
Source: University of California