The task of explaining love and romance has traditionally fallen to society’s poets, artists and playwrights, but recent advances have let scientists begin to understand love at the most basic level — the brain.

The tingles you feel when you’re around a loved one can be a powerful motivating factor, but neuroscientists have started unpacking the complexity of love by studying how the brain uses hormones to communicate with other areas of the body, and how they effect human emotions and behavior.

They’ve found that one such hormone, oxytocin, plays an important role in human relationships.

Oxytocin is produced in the hypothalamus and secreted from the posterior pituitary, a small gland roughly located behind your eyes.

Like many hormones, your brain uses oxytocin to initiate and regulate physiological changes in different parts of your body.

For example, the brain secretes oxytocinduring childbirth to tell the mother’s cervix to dilate and uterus to contract. Following birth, it plays a large role in promoting maternal care and parent/child bonding. Oxytocin is produced in the brain in response to breast-feeding and triggers the release of milk in the mother’s nipple.

Oxytocin influences other behaviors as well. Exposure to oxytocin increases many social behaviors, including facial recognition, eye contact, trust and cooperation. Subjects exposed to oxytocin are better at telling another person’s emotional state than control subjects, and are comparatively more cooperative and less stressed.

Oxytocin promotes what scientists call “affiliative behaviors” between individuals, which include touching or caring for one another, or simply spending time together. Studies show that more intensely attached couples have higher levels of oxytocin circulating in their blood. If the relationship is sexual, oxytocin levels spike during orgasm. It’s no wonder that oxytocin has been dubbed “The Love Molecule.”

But, like all things in science, reality is much more complicated. While oxytocin can make people seem more trustworthy and attractive, a recent study published in “Proceedings of the National Academy of Sciences” showed that it can also make some people more racist and ethnocentric.

In part of their study, researchers at the University of Amsterdam evaluated the effect of oxytocin on moral decision-making. Dutch subjects were presented with a hypothetical situation where they could save five innocent people by sacrificing someone else. In each scene, the single person was assigned either a stereotypical Dutch or Muslim name. Investigators found that the name did not affect the rate of sacrifice in the control group exposed to placebo, but when Dutch subjects were given a whiff of oxytocin, they were more likely to sacrifice the Muslim individual.

These results suggest that oxytocin does not evoke feelings of love indiscriminately, but instead promotes a strong sense of group loyalty. While more studies are certainly necessary to better understand oxytocin’s nuanced effect on human behavior, it certainly could have had a huge influence on group dynamics and social cohesion over the long course of human history. It seems that oxytocin may be “The Love Molecule” some of the time, but such an oversimplification doesn’t even begin to tell you the whole gloriously complicated story.