Larry Young and Brian Alexander, who recently released The Chemistry Between Us: Love, Sex, and the Science of Attraction, have dissected the emotional, biological and cultural reasons behind the real reason men love breasts.
The two authors believe heterosexual men are so fascinated by women's breasts thanks to a simple hormone released during nursing which helps to forge the powerful bond between mother and baby, which also creates an evolutionary drive for a strong nurturing bond between lovers.
Mr Young, a leading expert in the neuroscience of social bonding, wrote a column for the Huffington Post, explaining that 'biologically speaking,' the human male breast obsession is 'pretty weird'. 'Men are the only male mammals fascinated by breasts in a sexual context,' said Mr Young.
'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.'
He continued to say that women do enjoy attention on their breasts, after Roy Levin, of the University of Sheffield, and Cindy Meston, of the University of Texas, surveyed 301 people, which included 153 women, on breast stimulation.
'In fact, research indicates that when we're confronted with breasts, or even breast-related stimuli, like bras, we'll start making bad decisions (and not just to eat at Hooters).' Evolutionary biologists have suggested that because full breasts are mostly made up of fat, this signaled to a man that a woman is in good health, 'therefore a top-notch prospect to bear and raise children.'
However another hypothesis is based on the idea that many primates have sex with the male entering from behind, which has been used to explain why some female monkeys 'display elaborate rear-end advertising.'
Therefore in humans, it has been argued that women's breasts evolved to mimic the contours of her rear.
The authors dismiss both of these ideas, instead referencing a neurological explanation that links the same brain mechanisms used to promote a powerful bond between a mother and her infant.
'When a woman gives birth, her newborn will engage in some pretty elaborate manipulations of its mother's breasts,' they wrote.'This stimulation sends signals along nerves and into the brain. There, the signals trigger the release of a neurochemical called oxytocin from the brain's hypothalamus. 'This oxytocin release eventually stimulates smooth muscles in a woman's breasts to eject milk, making it available to her nursing baby.'They continued: 'But oxytocin release has other effects, too. When released at the baby's instigation, the attention of the mother focuses on her baby. The infant becomes the most important thing in the world.
'Oxytocin, acting in concert with dopamine, also helps imprint the newborn's face, smell and sounds in the mother's reward circuitry, making nursing and nurturing a feel-good experience, motivating her to keep doing it and forging the mother-infant bond. This bond is not only the most beautiful of all social bonds, it can also be the most enduring, lasting a lifetime.'
Because an oxytocin release focuses the brain's attention to a partner's face, smell, and voice, the authors believe that the combination of oxytocin release from breast stimulation, and the increase of dopamine from the excitement of foreplay and face-to-face sex, helps to create an 'association of the lover's face and eyes with the pleasurable feelings, building a bond in the women's brain'.