The reason we react this way when we’re mad or angry is an interesting combination of science and psychology. On a scientific level, our tear ducts just aren’t that advanced, explains Robert R. Provine, Ph.D., a professor emeritus of psychology and neuroscience at the University of Maryland, Baltimore County, and author of Curious Behavior: Yawning, Laughing, Hiccupping, and Beyond . “Only humans produce emotional tears,” he says. “And these emotional tears are recently evolved… While vocal crying is present in babies at birth, emotional tears don’t appear until three months after birth, which is a sign of recent evolution.” Provine explains that means these tears aren’t finely tuned to our specific emotions. So, although we tend to think of crying as a reaction to sadness or grief, our brains and tear ducts can’t differentiate between our specific emotions. That’s why you might have the same crying reaction to being mad, stressed, super happy, or sad. “Tears are not a precise signal,” he says. “They’re not broadly tuned to our emotions, and they’re less nuanced than we think they might be.”