Mapping Social Networks What we can learn from fruit bats.

(Posted on Thursday, March 6, 2025)

Key points

• A recent study discovered specialized cells in the hippocampus that map social connections.
• Studying Egyptian fruit bats, the team found cells that encode identity, sex, hierarchy and group affiliation.
• Studying these specialized cells may reveal insights into how we form and maintain social relationships.

Interacting with others can be challenging—just ask anyone who has ever tried to figure out group dynamics at a family gathering or navigate office politics. Recently, researchers studying the social behavior of Egyptian fruit bats discovered that social behavior is processed by the hippocampus, the brain’s hub for memory and navigation. Specialized cells in the hippocampus map social connections—tracking who to play with, who to avoid, and who might make a good mate. These findings may reveal surprising insights into how we navigate our social networks.

The Science of Social Behavior

Social behavior describes the ways individuals interact, communicate, and form relationships within a group. From cooperation and bonding to competition and conflict, how we interact with others shapes our daily lives. Our opinions of others are shaped by a myriad of factors, including proximity, similarity, and familiarity.

Inside the brain, complex chemical reactions mediate how we feel about another person or group. When you like someone, oxytocin is released. This is the “love hormone.” A mother bonding with her newborn releases large amounts of oxytocin. Even simply hugging another person triggers the release of hormones that foster trust and empathy. “Feel-good” neurotransmitters, dopamine and serotonin, also surge when you receive a compliment or share a laugh with another person. These brain chemicals uplift mood and drive you to seek out more rewarding social experiences.

In the event that you perceive someone as a threat, the brain triggers the release of cortisol, the stress hormone. Cortisol heightens defensiveness and social anxiety. With less oxytocin, dopamine, and serotonin being released, interacting with that person feels less rewarding. This fine line between like and dislike is regulated by the amygdala.

Nestled deep in the brain, the amygdala assesses social cues to drive our emotions and behavior. It can detect someone’s warmth and kindness, or perhaps aggression and hostility, to guide our response. In nature, sex, identity, and perceived hierarchy also influence whether an animal plays, mates, or fights with another. This study found that how the amygdala and higher regions of the brain respond to these cues may be governed by the hippocampus.

The hippocampus is not just the brain’s memory center—it also plays a crucial role in helping us navigate our surroundings. Specialized cells, called place cells, create mental maps that allow us to recognize familiar places, track locations, and form a sense of direction. Investigators found that these cells do a whole lot more than help us navigate physical spaces. Hippocampal place cells also seem to map our social connections, storing information about others and our interactions with them.

A Bat’s-Eye View of Social Mapping

The team made their discovery while observing the social behavior of Egyptian fruit bats. Wireless monitors were attached to their heads, enabling investigators to record neural activity in their hippocampus selectively. Simultaneously, video cameras inside the enclosure tracked the location of each bat using a small barcode that was attached to their bodies. For months, both male and female bats lived in this lab-based “cave,” where they were allowed to freely interact with each other. Living in groups of five to ten, the bats formed social hierarchies similar to those seen in nature.