Attraction is more than looks: it combines smell, hearing (voice) and the visual clues. Some are at the subconscious level, driving us towards a person without being able to explain it clearly. Biology dominates us. Even before being born, it is already determined how attractive we will be.
1.Symmetry. Even at the stage of fecundated egg, the human body starts developing from dividing cells. If each division went perfectly, we all would be perfectly symmetrical, the left and right sides being mirror images. But this never happens, due to environmental disturbances, as the organism does not live in a constant environment (food, temperature, humidity, predators and so on) and this slightly alters the division.
That's why any human and animal presents a certain degree of asymmetry between the right and the left side. Smaller symmetry means an individual has powerful genes enabling him to stand bad conditions and survive better, being more healthy and fertile.
"It makes sense to use symmetry variation in mate choice. If you choose a perfectly symmetrical partner and reproduce with them, your offspring will have a better chance of being symmetric and able to deal with perturbations." said evolutionary biologist Randy Thornhill of the University of New Mexico.
His symmetry researches on people revealed that both men and women rated more symmetrical members of the opposite sex as more attractive and healthier than their less symmetrical individuals.
All these differences are normally low, of a few percent (there is pathology, a disease causing too much asymmetry) but the brain perceives this, even if not consciously.
Men with higher symmetry also enjoy more sexual partners than men with higher asymmetry.
"Women's sex-partner numbers are dependent on things other than attractiveness," Thornhill told LiveScience.
"Because of the way that the sexual system in humans works, women are choosy. They are being sexually competed for. They have to be wooed and all that."
2. Body shape. Psychologist Devendra Singh of the University of Texas investigated people's waist-to-hip ratio (WHR) relationship with sexual attractiveness and found that women with a WHR of 0.7 (a waist much narrower than the hips) are most desirable to men. An analysis of Playboy models and Miss America contestants found that the majority were situated around a WHR of 0.7 or lower.
"In general, a range of 0.67 to 1.18 in females is attractive to men, while a 0.8 to 1.0 WHR in men is attractive to women, although having broad shoulders is more of a turn-on." said Singh.
WHR encodes a crucial fat clue: if the individual possesses enough energy to care for offspring.
The way fat is stored on the body is controlled by sex hormones. The proper levels of estrogen in women will produce the right WHR ratio and testosterone does the same in men.
People with the right WHO, no matter their weight, are less vulnerable to conditions like cardiovascular disorders, cancer and diabetes, and are more fertile, as revealed by many researches.
"The idea is that beauty is conveying information about health and fertility, and we admire that," said Singh.
3. The face is the first factor that tells the gender. And the person's fertility degree.
"Estrogen caps bone growth in a woman's lower face and chin, making them relatively small and short, as well as the brow, allowing for her eyes to appear prominent," Thornhill explained.
Testosterone carves masculine faces, with a bigger lower face and jaw and a prominent brow.
"Men and women possessing these traits are seen as attractive, because they advertise reproductive health." said Thornhill.