Scientists say root of jealousy is in the brain

Researchers from the University of California say jealousy increases brain activity in monkeys and humans.

Studying the neurobiology of jealousy in a monogamous primate model, the researchers had male titi monkeys watch their female partner interacting with a stranger male.

They subsequently introduced a control in which a male monkey watched an unknown female with an unfamiliar male. After 30 minutes of viewing, brain scans were performed to see which areas were activated by this activity.

According to the research which was published in Frontiers in Ecology and Evolution, brain activity in the monkey increased in the cingulate cortex, an area associated with social pain.

“Understanding the neurobiology and evolution of emotions can help us understand our own emotions and their consequences,” said Karen Bales, a professor at the University of California.

“Jealousy is especially interesting given its role in romantic relationships and also in domestic violence.

“The neurobiology of pair bonding is critical for understanding how monogamy evolved and how it is maintained as a social system.

“A better understanding of this neurobiology may also provide important clues on how to approach health and welfare problems such as addiction and partner violence, as well as autism.

“Male titi monkeys show jealousy much like humans and will even physically hold their partner back from interacting with a stranger male.”

The researchers also measured the levels of various hormones thought to be involved in pair bond formation, mating-related aggression, and social challenge. They saw heightened activity in the lateral septum, a brain region which plays a critical role in regulating processes related to mood and motivation.