Why do we decide to approach other people? According to new research from the Hebrew University of Jerusalem, the answer may begin unfolding in the brain several seconds before any movement takes place.
The study found that social behavior is preceded by a distinctive pattern of activity that spreads across the brain. Researchers also discovered that the strength of this neural pattern is linked to how socially motivated an individual is.
The work was led by Dr. Lilah Avitan and carried out by PhD student Imri Lifshitz and other members of Avitan’s laboratory at the Edmond and Lily Safra Center for Brain Sciences (ELSC) at the Hebrew University of Jerusalem.
Tracking Social Decisions in Real Time
To investigate how the brain turns social information into action, the researchers used zebrafish, a model organism that allows scientists to monitor brain activity at the level of individual cells.
The team created a new experimental system in which one fish watched and responded to another fish that was swimming nearby. While this happened, researchers recorded activity throughout the observer fish’s entire brain in real time.
This setup allowed them to examine the neural events leading up to a social decision and follow the process as it unfolded moment by moment.
A Brain-Wide Signal Appears Before Social Behavior
The researchers found that when a fish was about to swim toward another fish, changes in brain activity began several seconds before the movement itself.
Instead of relying on a single brain region dedicated to social behavior, the process involved coordinated changes across multiple parts of the brain.
Activity increased in the pallium, a higher brain region associated with complex behaviors. At the same time, activity decreased in other brain areas.
Together, these changes created what researchers describe as a neural “pre-decision state.” This brain-wide pattern signaled that a social action was about to occur and could be used to predict the behavior before it happened.
Brain Activity Linked to Social Drive
The study also revealed that the strength of this neural signature varied among individuals.
Fish that showed a stronger brain-wide pattern tended to be more social overall, suggesting that the neural signal reflects an individual’s underlying social drive.
The findings further highlighted the importance of the pallium. Results suggest that this brain region plays a central role in generating the motivation to approach others and engage in social interactions.
“This study identifies a brain-wide neural signature of social approach that emerges before movement begins,” said Dr. Avitan. “This signature predicts not only whether an upcoming action will be social, but also how strongly socially driven the individual is.”
What the Findings Could Mean
Understanding how the brain generates social behavior may help researchers better explain why some individuals are naturally more social than others.
Because similar brain structures contribute to social behavior across many species, the findings could also offer clues about human social function and conditions in which social behavior is altered or disrupted.