Kable and his team found the people who chose to take the biggest gambles tended to have larger amygdalae, with fewer connections to the medial prefrontal cortex. But despite having fewer links, the activity of these two regions seemed more coordinated — a measure called functional connectivity — among those who preferred to take their chances, compared with those who would rather play it safe.

The results are impressive, if a little hard to decipher, according to Ifat Levy, a neuroscientist at the Yale University School of Medicine who did not work on the new study. Kable and his colleagues’ use of different types of scans provides a far more detailed picture of the interplay between brain anatomy and risk than does earlier research, Levy says. “[In our work] we used only one of these techniques out of the three here,” she adds. Levy’s research found a connection between risk preferences and the quantity of neurons in a different part of the brain (called the posterior parietal cortex), but not the amygdala or medial prefrontal cortex. “So [the new study is] a fuller picture of the anatomy and function of the brain in relationship to risk-taking,” she says.