The brain is a sex organ

13-19 February 2015 #745 Nepali Times Buzz

Love is in the air again: on cable television, in social media, and through peer pressure. Popular songs, poems, and books about love state that love is deeply rooted in the heart. It’s not.

Decades of research have shown that it is our master organ, the brain, which orchestrates the feeling of love by secreting the special chemicals that make romance possible.

This cocktail of love includes brain hormones that have specific roles to play during different stages of love. When one begins to fall in love, the level of adrenaline in the body spikes up making your heart beat faster, the mouth drier, and the body starts to sweat. There is a surge in dopamine levels that triggers intense pleasure, increases energy, and decreases need for food and sleep.

Finally, the level of the neuro-transmitter serotonin drops, leading the subject to start obsessing about a new-found partner which is also observed in people with obsessive-compulsive disorder. In the next phase, the hormones oxytocin and vasopressin are released which bonds partners and are released during sex. Oxytocin, known as the “love hormone”, is also released in mothers during childbirth or is triggered by the sound of a baby crying.

The release of these brain hormones is exquisitely controlled, and not secreted at the sight of just any stranger, thus preventing love catastrophes. There are elaborate mechanisms in place to allow the brain to evaluate if the partner is deemed attractive and worthy of a shot at love. These ingrained evolutionary laws of attraction are exceedingly complex and may rely on sensory cues of sight, sound, and smell.

Psychologists have discovered that both males and females are attracted to certain physical traits. Males tend to find women with a waist narrower than hips (0.7 waist hip ratio) and high-pitched voice more desirable. Women tend to find males with broad shoulders, some facial hair, and deeper voice more attractive. But women also rate non-physical qualities such as intelligence, emotional stability, and friendliness very highly, throwing any supposed laws of attraction into disarray.

Body odour (due to pheromones) of a partner is known to play a critical role in love, attraction, and subsequent bonding. While sniffing a partner may be deemed creepy, many double-blinded studies have shown that both males and females are attracted to partners with an MHC (Major Histocompatibility Complex) – a cluster of genes that determine body odour different from their own. There is evidence that many long-lasting couples have vastly different MHC genes suggesting that the biological compatibility of love may hinge subconsciously on the partner’s smell.

The brain integrates this complex array of conscious and subconscious cues to help people fall in love. But why do we have such vast, multi-layered checkpoints? Perhaps because of the subconscious probability of having a healthy offspring. For example, fertility in women is associated with the same waist-hip ratio that men find desirable. The difference of MHCs between parents may ensure a healthy immune system in children. It is plausible that through the blend of love chemicals and attraction cues, the brain may be tricking us into falling in love to ensure reproduction. And what better way to assure a healthy offspring than from two people in love and committed to one another?

Thus, it is clear that love isn’t blind. Perhaps the peculiar and dramatic behavior seen in love-struck couples may simply be a manifestation of their brains. But wouldn’t it also be nice if someone strummed a song or two about the brain rather than just the heart?