Fast food restaurant Hooters, Playboy magazine, and Hustler have helped feed America’s obsession with breasts. Every year, millions of dollars are spent on breast enhancements, from push-up bras to plastic surgery, to showcase this form of the female body. But the cultural fascination with boobs, specifically for men, is deeply tied to our species' survival instinct.

Breasts have not only evolved as a means of feeding but as a measure of mate selection for men. A woman’s breast size can reveal a plethora of information regarding her age and fertility. This is why men unconsciously are on the prowl for a woman with the right chest-to-waist-to-hip ratio.

Larry Young and Brian Alexander, authors of the book The Chemistry Between Us: Love, Sex, and the Science of Attraction, have dissected the emotional, biological, and cultural reasons behind why men love breasts. They affirm a woman’s chest is an area that naturally revs up a man’s sexual drive.

"Men are the only male mammals fascinated by breasts in a sexual context," Young wrote. "And women are the only female mammals whose breasts become enlarged at puberty, independent of pregnancy. We are also the only species in which males caress, massage, and even orally stimulate the female breasts during foreplay and sex."

When a man touches, massages, or nibbles a woman’s breasts, it sparks the same process of brain events as nursing. A baby’s stimulation of its mother’s breasts triggers the release of oxytocin from the hypothalamus, which promotes mother-infant bonding. This explains why human sexuality has “exploited” the mother-infant bonding brain circuitry to establish bonds between lovers.

Men’s obsession with breasts is not only biological, however. It can also reveal their personality traits.

1. Hungry men prefer big breasts.

Large breasts are subconsciously seen as “food security” for men because they act as a signal for fat reserves, which translates to access to an abundance of resources. Since ethnicity is known to influence breast size preferences, a group of British researchers sought to examine the effect hunger and satiety had on white British men’s breast size preference, to eliminate any factors that may affect the outcome. The two-part 2008 study published in The Journal of Socio-Economics found hungry men preferred larger breasts compared to satiated men. It seems resource security significantly impacts a man’s preference in breast size.

2. Sexist men prefer big breasts.

A man’s attitude toward women and their role in society may influence his preference in their bust size. In a 2013 study published in the journal Archives of Sexual Behavior, over 300 white men ages 18 to 68 were shown 3D models of women with a range of breast sizes. The participants were asked to identify which women they found most attractive, followed by completing a survey measuring hostility and attitudes toward women, relationships, benevolent sexism, and how much a man objectified a woman.

The study found men who have sexist views toward women are more likely to find big breasts attractive. These men admitted to displaying behavioral traits of sexism and hostile attitudes toward women. Moreover, men perceived women with large and very large breasts with “traditional” femininity and as “meek and weak.”

3. Men who want a submissive partner prefer small breasts.

A man’s preference for small breasts may indicate his desire for a submissive partner. Psychologist Stuart Fischoff believes these men want a more submissive, non-threatening partner who’s more likely to be loyal.

“Also, you may get the psychological hint that she’s not trying to compete with other women who have larger breasts, and therefore she’ll be loyal to you. Or maybe the very first girl you had a crush on had small breasts, and if she constructed your earliest example of what’s sexy, her memory may still lead you to find small-breasted women exciting,” he told Men’s Health.

4. Men who are independent and non-nurturant prefer large breasts.

A male who prefers a top heavy set woman may be more likely to have a need for heterosexual contact and for exhibitionism, according to a study published in the Journal of Personality and Social Psychology. In other words, he’ll say witty things and be the center of attention. Also, a large breast preference was associated with a “Playboy” image.

5. Men financially stable prefer small breasts.

The amount of money he earns could dictate the size of breasts he prefers. A 2008 study published in The Journal of Socio-Economics found a link between financial security and men’s breast size preference. The study found financially unstable men or those going through “resource security” have a preference for larger breasts while their financially well off counterparts had a tendency to like smaller breasts. This suggests wealthy men who have plenty of resources don’t need a woman with excessive fat reserves, unlike their unwealthy counterparts who seek abundance.

6. Men ready for fatherhood prefer large breasts.

A man ready to procreate may favor large breasts over small breasts from a reproduction standpoint. According to a 2012 study published in the journal Archives of Sexual Behavior, the desire to remain childless was associated with a preference for a combination of smaller breasts and larger waist-to-hip ratio. Men who wished to become a dad chose women with larger breasts. This is not surprising, since larger breasts are a signal of a woman’s capacity and ability to bear and nurture children.

Although a man’s size preference does reveal more about his personality and attitude, though, in the end, he'll always love breasts — no matter the size.