You Think Like a Girl

by Michelle Starr

Never mind those two famous planets—researchers at the California Institute of Technology and Baylor University have found new evidence that male and female earthlings are wired differently.

The documentation: Brain scans detailing activity in men and women playing an investment game with an anonymous partner.

One subject received 20 monetary units and could keep them or invest any portion with an unknown “trustee” subject in another lab, miles away. The money invested would triple every time, but the trustee could choose how much of the profit to return to the original investor. The invest-and-return cycle ran up to ten times, while a functional magnetic resonance imager, or fMRI, captured pictures of local brain activity, scanning the players’ brains every two seconds.

As men contemplated their risk-and-reward options, activity rose in the area of the brain associated with conflict resolution, says Steven Quartz, director of Caltech’s social cognitive science laboratory. Once they decided, the flurry stopped.

Women’s brains remained relatively calm until after they made their decisions. Then, the portion of the brain stem associated with reward and the frontal area responsible for the ability to think about other people lit up, reaching a peak just before the other player responded.