What really makes us think someone is hot?
Neuroscientists know that a behavioral “attraction system” seems to activate nerve cells in the midbrain to release the neurotransmitter dopamine when we like someone, but they don’t know why only some potential mates trigger this reaction.
Over the years science has come up with a few ideas, though. One is the “golden ratio,” or basically the idea that the ratio of certain parts of the face to other parts of the face create an attractive face. Modern scientists know our eyes are immediately drawn to faces that are about 1.6 times longer than they are wide and that have bottom lips 1.6 times fuller than their upper lips– but it’s not proven whether people associate the ratio with attractiveness.
Beyond that, a 2015 study found that up to one in three people have some amount of facial asymmetry, and not that many people find themselves without mates. In addition, a 2002 study found that what we see as hot changes over time– there’s never been any consistent hip-to-waist ratio among Miss America winners of Playboy centerfolds. Other things that play a role in how attractive we find someone: how well they play the dating game, conversation dynamics, mood, and other seemingly random factors.
In other words: science hasn’t reliably come up with a way to precisely tell if two people are going to hit it off and be romantic partners or not. (PopSci)