Yawns are more contagious among people with closer relationships.
163
Women rate men more attractive if other women are looking and smiling at him.
17
Brain scans show that people who view photos of a beloved experience an activation of the caudate - the part of the brain involving cravings.
103
Historically, sweat has been an active ingredient in perfume and love potions.
309
Kissing releases masses of oxytocin, a "love potion" that helps couples bond and feel more attracted to each other.
13
Intelligent men tend to be more sexually faithful.
31