Stimulating two brain areas, nudging them to collectively fire in the same way, increased a person's ability to behave altruistically, according to a study published February 10th in the open-access journal PLOS Biology by Jie Hu from East China Normal University in China and colleagues from University of Zurich in Switzerland.
As parents raise their kids, they often work to teach them to be kind and to share, to think about other people and their needs—to be altruistic. This unselfish attitude is critical if a society is going to function. And yet, while some people grow up to devote themselves to others, other people still manage to grow up selfish.
To understand what brain areas and connections might underlie individual differences in altruism, the researchers asked 44 participants to complete 540 decisions in a Dictator Game—offering to split an amount of money with someone else, which they then got to keep. Each time, the participant could make more or less money than their partner, but the amounts varied. As the participants played the game, the researchers stimulated their brains with transcranial alternating current stimulation over the frontal and parietal lobes of the brain. The stimulation was set up to make the brain cells in those areas fire together in repetitive patterns, training them all to either gamma or alpha oscillation rhythms.
The authors found that during the alternating current stimulation designed to enhance the synchrony of gamma oscillations in the frontal and parietal lobes, the participants were slightly more likely to make an altruistic choice and offer more money to someone else—even when they stood to make less money than their partner. Using a computational model, the researchers showed that the stimulation nudged the participants' unselfish preferences, making them consider their partner more when they weighed each monetary offer. The authors note that they did not directly record brain activity during the trials, and so future studies should combine brain stimulation with electroencephalography to show the direct effect of the stimulation on neural activity. But the results suggest that altruistic choices could have a basis in the synchronized activity of the frontal and parietal lobes of the brain.
Coauthor Christian Ruff states, "We identified a pattern of communication between brain regions that is tied to altruistic choices. This improves our basic understanding of how the brain supports social decisions, and it sets the stage for future research on cooperation—especially in situations where success depends on people working together."
Coauthor Jie Hu notes, "What's new here is evidence of cause and effect: when we altered communication in a specific brain network using targeted, non-invasive stimulation, people's sharing decisions changed in a consistent way—shifting how they balanced their own interests against others'."
Coauthor Marius Moisa concludes, "We were struck by how boosting coordination between two brain areas led to more altruistic choices. When we increased synchrony between frontal and parietal regions, participants were more likely to help others, even when it came at a personal cost."
In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: https://plos.io/457RtCK
Citation: Hu J, Moisa M, Ruff CC (2026) Augmentation of frontoparietal gamma-band phase coupling enhances human altruistic behavior. PLoS Biol 24(2): e3003602. https://doi.org/10.1371/journal.pbio.3003602
Author countries: China, Switzerland
Funding: see manuscript
