We've all said it at some point: “That’s just the way I’m wired.” Usually it’s meant as a throwaway line about quirks or habits, but science shows there may be more truth to that phrase than we realize — especially when it comes to generosity and altruism. It all comes down to two almond-shaped structures located in the lower part of the brain known as the amygdalae. Within this complex lies the basolateral amygdala (BLA), which is credited with, among other feelings, kindness and thoughtfulness toward others.
In 2015, a collaborative study conducted by Yale and Duke universities reached that likely conclusion by testing monkeys. Researchers found that when given juice, the monkey group that received higher levels of oxytocin — a neurotransmitter that promotes positive feelings of love and connection — was more likely to share their juice with others. Because oxytocin directly affects activity in the amygdala, the brain region tied to emotion and decision-making, these monkeys made more prosocial choices; in other words, they were more generous.
Ten years later, a 2025 study conducted by researchers at Heinrich Heine University in Düsseldorf tested similar effects in humans, using patients with a rare condition known as Urbach-Wiethe disease. The disorder can cause calcium deposits in parts of the brain and damage the BLA. Because the subjects' amygdalae don’t function normally, researchers found changes in their emotional processing. That led them to explore further how the amygdala might impact everyone’s social behavior, not just those with the condition. They designed an experiment with two groups: people with the disease and those without. Each group was asked how much money they would be willing to offer to friends, family and even strangers. As it turned out, the Urbach-Wiethe group proved less generous overall than the control group, suggesting that a healthy amygdala may help regulate the balance between self-interest and compassion.
A separate study of patients with the same disease assessed their responses to a series of ethical dilemmas, including one in which participants were asked to decide whether they would support an act of sacrifice by one person that would save thousands of other lives. Overall, the healthy control group agreed the sacrifice would be worth it, but those with BLA damage — the Urbach-Wiethe patients — mostly did not.
For Dr. Abigail Marsh, a professor in the Department of Psychology and the Interdisciplinary Neuroscience Program at Georgetown University, the results of both studies, on humans and other primates, make sense.
“The amygdala is a pretty similar structure across all mammalian species, from hamsters to humans. I call it the switchboard that helps coordinate complex behaviors and states. That includes states like fear and relevant behaviors like escape, as well as social behaviors like helping others.”
Dr. Abigail Marsh
Marsh adds, “Humans are, in the scheme of things, a very altruistic species. It's likely our amygdala has something to do with that.”
Age also plays a role. Evidence points to children, whose amygdalae are smaller than adults’, being prone to less favorable behavior, like callousness and psychopathy, especially if they’ve experienced mistreatment. By the time they’re older, their amygdalae are fully grown, which is linked to becoming more altruistic.
Interestingly, a healthy amygdala has also been shown to play a role in parenthood. In rats, Marsh notes that oxytocin’s effects cause mother rats to try to protect their offspring from danger. “What is very clear in animals is that oxytocin stimulates parental care, promoting caring, altruistic behaviors. A couple of very recent studies in mice have found that the release of oxytocin and the activity of the amygdala play a direct role in causing mice to try to ‘rescue’ other mice who were unconscious.” She adds, “It’s a reasonable guess that something similar is going on in humans.”
However, Marsh points out, “Our technology has improved a lot in recent decades, but not enough to know this information for sure.” That means that the outcome of current human experiments, like the Yale-Duke study, was based solely on comparative results, not confirmed scientific evidence. “We have to extrapolate what we know from animals the best we can,' she says, adding that the Düsseldorf study is the best direct data on humans to date.
Marsh’s own findings say that people who have extreme altruism have larger-than-normal amygdalae. For men, extreme altruism might look like taking brave, risky acts to help others. For women, it may be a different kind of personal sacrifice, such as donating a kidney.
Both groups show dramatically reduced social discounting — the tendency for people to care less about the well-being of others, which may be correlated with a specific band of brain tissue that includes the amygdala. The results, Marsh says, show a causal role in calculating the value of others’ welfare. Could the amygdala also play a role in making us more sensitive to others and increasing our desire to help them? “Lots of evidence points to that possibility, but we don’t have direct evidence,” she explains.
Beyond science, Marsh says, “I want to emphasize that most people are capable of enormous empathy, compassion and generosity at baseline. We are a much, much kinder species than we tend to give ourselves credit for. That is partly due to both traditional media and social media, which like to pummel us with stories about terrible things people do and distort our understanding of human nature. On average, people are becoming more prosocial over time, not less. But we could always do even better.”
The Amygdala & The Holidays
The holidays are naturally associated with goodwill toward others and the spirit of giving, but could the amygdala also play a part?
“Many families have traditions of helping those in need,” says Marsh. Since research suggests the amygdala, a region tied to empathy and generosity, helps inspire kindness, it’s logical to connect it to the desire to help others. That could look like anything from doing something thoughtful for a stressed-out family member to working in a food kitchen for those in need.
Marsh notes that acknowledging gratitude is also associated with the holidays, Thanksgiving in particular. Realizing the way we have benefited from kindness and support from others promotes a sense of humility that makes us eager to pass on good deeds.
Beyond the emotional aspect of generosity, it may also have a financial impact. In a study published by JNeurosci, participants played an economic game that allowed them to earn different amounts of money. Once the money was banked, they were offered the chance to donate some of it to charity. While oxytocin did not affect whether or not they chose to donate, it did show that those who received oxytocin gave substantially more than the placebo group.
Could the amygdala play a role in making us more sensitive to others and increasing our desire to help them, especially this time of year?
It’s a question Marsh would love to know the answer to: the actual neuroscience behind why a holiday that reminds us to be thankful also moves us to want to help others in our community. “In general,” she concludes, “I hope we can work toward a better understanding of ways to promote gratitude, generosity and altruism.”