4. Looking older
A study in 2012, published in the Journal of Evolutionary Psychology, found that women prefer men who look older.
The more financially independent women became, the more they said they liked older guys, according to the study.
One explanation for what researchers have coined the "George Clooney Effect" could be that women are only fertile from puberty to menopause, while men can father a child until much later. Women may get a better offer by waiting until the man has more status and resources due to being older.
5. Facial hair
Some people love a bushy beard, whereas others go for clean-shaven men. A study in 2013 recruited 177 men and 351 women to look at pictures of men who had no facial hair, light stubble, heavy stubble, or a full beard.
The results showed that women thought the most attractive beard length is heavy stubble, or about 10 days of growth.
Heavy beards, light stubble, and clean shaven were all equally less attractive than heavy stubble.
6. Facial scars
This one depends on if you're attracted to men or women. One study, published in the journal Personality and Individual Differences, found that men could be considered more attractive if they had a facial scar, whereas this wasn't found for women.
Researchers took photos of 24 male and 24 female students and manipulated them to look like they had scars on their faces. Then, another 200 students were asked to rate how attractive the photos were, and whether they thought the person would be good for a short or long-term relationship.
Men with scars were rated as more attractive for short-term relationships than men without scars. There was no difference in how attractive women were with or without scars.