You can think of human psychology as a series of overlapping mental programs. One program identifies faces as individuals we recognize. Another is working memory, which allows us to make quick calculations in our heads. These programs were coded by evolution and help us survive every day; they are the sources of our ingenuity and our compassion. They are everything we are.

These mental programs — etched in all of us — are also the sources of horror and pain.

Nour Kteily is a psychologist at Northwestern University whose research is about understanding one of the darkest, most ancient, and most disturbing mental programs encoded into our minds: dehumanization, the ability to see fellow men and women as less than human.

Psychologists are no strangers to this subject. But the prevailing wisdom has been that most people are not willing to admit to having prejudice against others.

Kteily suspected otherwise. And so he and his colleagues created a new way to measure people’s levels of blatant dehumanization of other groups. It’s not subtle.