The Science of Chocolate

by Ivy Shi

This Valentine's Day, it is predicted that Americans will dish out $1.6 billion dollars for chocolates. Often considered the most romantic of treats, chocolate has earned a reputation as the “taste of love.“ In preparation for the most romantic day of the year, some of the leading scientists have questioned and identified what's responsible for the sensual and addictive qualities of chocolate.

The key to chocolate's close association to love lies in its ability to manipulate our hormones. Although love is often perceived as an intangible and profound experience, its effects can be explained scientifically through a handful of hormones. Incidentally, consumption of chocolate can trigger similar hormonal pathways. On that account, an understanding of the mechanics of love can reveal the secrets of the world's most popular confection.

In the scientific world, love isn't classified as an emotion, but rather a goal-oriented motivational state which drives the human race to reproduce and survive. An experiment performed by psychology professor Arthur Arun, Ph.D., of New York has presented support for the hypothesis that the impetus to mate is a powerful biological function. Arun paired together complete strangers and asked them to share intimate details about themselves with their assigned partner for 30 minutes. The strangers were then asked to stare into each others’ eyes for 4 minutes without speaking. Many of his subjects confessed to feeling deeply attracted to their partners after the experience, and two subjects even went on to get married. These results indicate that an instinctual and evolved behavior lies behind locking eyes and feeling attraction.

In another study, evolutionary biologist Randy Thornhill, Ph.D., of the University of New Mexico investigated the role of symmetry in the perception of male attractiveness. According to researchers, symmetrical men are typically perceived as more attractive by women because symmetry serves as a marker for genetic “fitness,“ while asymmetrical appearances are indicators of higher frequency of mutation. The series of studies, published in the journal of Animal Behavior in 1995, even showed that the smell of symmetrical men is preferred by women, and that women experience higher rates of sexual orgasm when their partner's features are symmetrical.

These studies highlight the overwhelming role that biology plays in the experience of love. Helen Fisher, Ph.D., a leading biological anthropologist and researcher at Rutgers University, has outlined the three stages of human love: lust, attraction, and attachment. The first stage, lust, is driven by testosterone and estrogen, two widely known sex hormones. Fisher says these hormones will “get you out looking for anything.“

The second stage, attraction, is characterized by the love-struck, obsessive feeling. Scientists attribute most of this response to three neurotransmitters: adrenaline, dopamine, and serotonin. Adrenaline activates the sympathetic nervous system, which causes the heart to race and the body to perspire. Dopamine triggers intense feelings of pleasure, and studies have shown that it has similar effects on the brain in “love-struck“ couples as cocaine and nicotine does on addicts. Finally, serotonin is responsible for feelings of well-being and causes the object of our affection to constantly command our attention and become our obsession.

Ellen Berscheid, Ph.D., a leading researcher on the psychology of love, says that newly smitten partners are especially prone to cognitive bias. They overwhelmingly tend to idealize their partners, overstating their virtues and explaining away their flaws. As Berscheid states, “It's very common [for new partners] to think that they have a relationship that's closer and more special than anyone else's.“ This rose-tinted view is likely attributed to a desire for partners to stay together and enter the final phase of love-attachment.

Attachment is what causes couples to stay together long enough to give birth and raise children. This bond is often formed through sexual intercourse, which releases two key hormones: oxytocin and vasopressin. Oxytocin is also released by the hypothalamus gland during childbirth and has been found to cement the bond between mother and child. Diane Witt, Ph.D., a psychology professor from New York, has shown that if you repress oxytocin during childbirth in sheep and rats, they reject their own young. Oxytocin may play a similar role in forming the strong bond between couples.

The second key hormone, vasopressin, retains water in the body through the kidneys and prevents thirst. Vasopressin is also released during intercourse and has been found to be strongly correlated with partner attachment. In a study of prairie voles, when the release of Vasopressin was blocked, male prairie voles immediately lost devotion to their partners and neglected to protect them from competing males.

So why is chocolate such a romantic treat? Studies have shown that chocolate contains tryptophan, a chemical that is used to produce serotonin, which, as described, is key to the attraction stage of love and contributes to chocolate's addictive quality. Chocolate also contains a neurotransmitter phenylethylamine, which has been found to stimulate the brain's pleasure center, similar to oxytocin. Phenylethylamine reaches peak levels during the climax of sexual intercourse, making the consumption of chocolate nearly comparable to the act of lovemaking. These close associations with the experience of infatuation pay homage to chocolate's reputation as the taste of love.

Love, eternalized in song, dance, art, and words, is certainly a personal experience for all individuals. Yet however personal it may feel, the concept of love can be understood through a scientific perspective as a physical process. As we enter the most romantic season of the year, keeping in mind that the sweet treats we're eating might hold the secrets to our hearts is a thought-provoking concept that can expand our understanding of our personal relationships and our culture as a whole.