"Darwin would have loved the fist bump," says Dacher Keltner, professor of psychology at the University of California, Berkeley.

In this clip from National Geographic's "Going Deep With David Rees," we learn about the fist bump from an evolutionary perspective and how its social significance is different from that of your run-of-the-mill handshake.

"The fist bump honors one of Darwin's evolutionary principles of communication, which is the principle of antithesis," Keltner says in the video. "You take a signal, which could [mean] 'up yours,' or 'I'm going to do some damage,' and you convert it to its opposite meaning, which is 'we're buddies.'"

Open hands (like in a handshake), however, normally symbolize an invitation without much interpretation needed.

Not only is the fist bump a gesture born out of social evolution, but studies also show it's more hygienic than a high five or handshake.

So next time you want to say "hi," show off how "evolved" you are with a friendly fist bump.