A new study from Dartmouth College researchers found that people could predict whether a female politician would win or lose an election within just 380 milliseconds of seeing a photo of her face. Turns out, how feminine women’s facial features are says a lot about their electoral success.

Using software that tracks computer mouse movements, researchers showed nearly 300 participants photos of politicians’ faces—the winners and runners-up in U.S. Senate and gubernatorial elections between 1998 and 2010. They then asked the participants to characterize those faces as male or female, and tracked how fast they made their decision. When participants saw a photo of a woman with relatively masculine features, they tended to hesitate before characterizing her as “female.” Photos of women with feminine features met with less uncertainty.

It’s this pause, this gut reaction, that became the predictive factor of electoral success. The more participants were drawn to select the male response when categorizing the gender of a female politician’s face, the researchers found, the less likely she was to win her election.