Betty Everett was right!
Recent studies have found that saliva contains chemical and hints of evolutionary fitness, so when you're swapping spit with your significant other, you're literally giving them cues and chemicals that describe to them if you'd be a good fit.
It also promotes pair bonding, decreases cortisol, and burns calories. What's not to like?
Brought to us by Helen Fisher, Rutgers University, at the annual conference of the American Association for the Advancement of Science (AAAS) in Chicago. She is the official "love" anthropologist who studies human bonding, and who they pull out every Valentine's Day to explain why we love each other. But overall pretty sweet gig.