Brain stimulation boosts generosity by synchronizing two brain regions

Brain stimulation can make people more generous

Scientists have found they can slightly increase altruistic behavior by synchronizing activity between two specific brain regions. The research, led by Jie Hu of East China Normal University, was published February 10th in the open-access journal PLOS Biology.

The team used a noninvasive brain stimulation technique on 44 participants while they played a financial decision-making game. By aligning the firing patterns of neurons in the frontal and parietal lobes, the researchers observed a measurable shift toward more generous choices.

The dictator game experiment

Participants made 540 decisions in a version of the Dictator Game. In each round, they chose how to split a sum of money with another person, and they got to keep whatever they decided to give themselves.

The payout amounts changed every round. This meant participants could end up with more or less money than their partner, testing their willingness to share even at a personal cost.

During the task, researchers applied transcranial alternating current stimulation. The goal was to coordinate neuron firing in the frontal and parietal lobes into specific rhythmic patterns.

• The stimulation created either gamma or alpha oscillations.
• Gamma rhythms are associated with higher cognitive functions.
• Alpha rhythms are often linked to resting states.

Gamma synchrony drove the change

The key finding was that only gamma synchrony increased altruism. When stimulation strengthened gamma-wave alignment between the two brain regions, participants showed a modest increase in generous decisions.

They were more likely to share larger amounts, even when it meant they would earn less money than their partner. A computational model revealed the stimulation changed how people evaluated the offers.

"After stimulation, individuals placed greater weight on the other person's outcome when deciding how to divide the money," the authors wrote. The study did not directly measure neural activity during the experiment, a limitation the team notes for future research.

A causal link in the brain

The researchers say this demonstrates a cause-and-effect relationship. Altering communication in this specific brain network consistently changed social decision-making.

"What's new here is evidence of cause and effect," said coauthor Jie Hu. "When we altered communication in a specific brain network using targeted, non-invasive stimulation, people's sharing decisions changed in a consistent way."

Coauthor Christian Ruff stated the work identifies a brain communication pattern tied to altruistic choices. This improves the basic understanding of how the brain supports the decisions that enable cooperation.

Marius Moisa, another coauthor, noted the team was struck by the clear effect. "When we increased synchrony between frontal and parietal regions, participants were more likely to help others, even when it came at a personal cost."

Future research and implications

The authors emphasize that their stimulation technique did not directly measure changing brain signals. Future studies combining this stimulation with tools like electroencephalography could confirm how the intervention alters neural activity.

This research sets the stage for deeper investigation into the brain mechanics of cooperation. Understanding these circuits could be relevant for situations where collective success depends on people working together effectively.

The findings suggest synchronized activity between the frontal and parietal lobes is a component of altruistic decision-making. It is one piece of the complex puzzle explaining why some people are consistently more selfless than others.