Summary: Researchers have discovered that “tuning” the communication between two specific brain regions can make people act more unselfishly. By using non-invasive transcranial alternating current stimulation (tACS), scientists synchronized the firing patterns of the frontal and parietal lobes in 44 participants.
When these areas were nudged into a shared “gamma” rhythm, participants became significantly more likely to share money with others during a decision-making game, even when it came at a personal financial cost. The study provides direct evidence that altruism isn’t just a fixed personality trait, but a behavior supported by the synchronized coordination of specific social-decision networks in the brain.
Key Facts
- The “Altruism Network”: The study targeted the connection between the frontal and parietal lobes, areas known for high-level social processing and decision-making.
- Gamma Synchrony: Boosting the coordination of gamma oscillations (fast-paced brain waves) led to a consistent shift toward more generous choices.
- The Dictator Game: Participants made over 500 decisions on how to split money; those under stimulation placed higher value on their partner’s needs than their own.
- Causal Evidence: Unlike previous studies that only observed brain activity, this research used stimulation to prove that altering brain communication directly changes how people balance self-interest against others.
Source: PLOS
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.”
Key Questions Answered:
A: Not exactly “make” you, but it can “nudge” you. The stimulation didn’t force a specific choice; instead, it improved the communication between brain areas that weigh your interests against others, making you naturally more considerate of the other person.
A: Think of them like two offices in a company. One office (frontal) handles your goals and values, while the other (parietal) helps process the social context. When they are in sync, they share information more efficiently, allowing for more balanced, prosocial decisions.
A: While the research helps us understand how the brain supports cooperation, it’s currently a tool for basic science. However, it sets the stage for future work on improving social collaboration or understanding disorders where social cooperation is impaired.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neurotech and altruism research news
Author: Claire Turner
Source: PLOS
Contact: Claire Turner – PLOS
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Augmentation of frontoparietal gamma-band phase coupling enhances human altruistic behavior” by Hu J, Moisa M, Ruff CC. PLOS Biology
DOI:10.1371/journal.pbio.3003602
Abstract
Augmentation of frontoparietal gamma-band phase coupling enhances human altruistic behavior
Cooperation, productivity, and cohesion in human societies depend on altruism, the tendency to share resources with others even though this is costly.
While altruism is a widely shared social norm, people vary strongly in their inclination to behave altruistically, in particular across situations with different types of inequality in resource distribution.
What neurobiological factors underlie this variability? And can these be targeted by interventions to enhance altruistic behavior?
Here, we build on electroencephalography (EEG) evidence that altruistic choices during disadvantageous inequality correlate with oscillatory gamma-band coherence between frontal regions (representing other’s interest) and parietal regions (representing neural evidence accumulation).
We apply a transcranial alternating current stimulation protocol designed to exogenously enhance this fronto-parietal coherence and find that this leads to increased altruism, specifically during disadvantageous inequality as hypothesized based on the EEG findings.
Computational modeling reveals that this transcranial entrainment does not just add noise to the decision process but specifically increases the weight individuals assign to other-regarding concerns during choices.
Our findings show that altruism can be enhanced by neurostimulation designed to enhance oscillatory synchronization between frontal and parietal areas.
This establishes a neural basis for altruism and identifies a neural target for interventions aimed at improving prosocial behavior.
