Our Amygdala Influences Kindness and Altruism, Not Just Fear

Oxytocin drives kindness, altruism, and prosocial behavior via the amygdala.

Posted Dec 16, 2015

Vaclav Volrab/Shutterstock
Source: Vaclav Volrab/Shutterstock

Your amygdala are two almond-shaped groups of nuclei located deep within the front part of your brain's temporal lobes. Traditionally, the amygdala has been associated with a broad range of negative emotional conditions including: fear, phobias, anxiety, and post-traumatic stress disorder (PTSD). 

However, recent cutting edge neuroscientific research has revealed an unexpected twist—the amygdala is actually involved in a much broader range of emotions beyond fearfulness. As it turns out, the amygdala isn't simply the brain's "fear center." In fact, a new collaborative study by researchers from the University of Pennsylvania, Yale University, and Duke University found that the amygdala plays an important role in prosocial behaviors such as kindness, altruism, and charitable giving.

Typically, damage or maladaptation of the amygdala is linked with impaired social skills. Our amygdala helps us interpret other people’s facial expressions, emotional cues conveyed by the eyes, and someone's shifting gaze. Interestingly, the researchers of the recent study report that the neuropeptide oxytocin (OT)—often referred to as the “love hormone”—has the ability to influence magnanimous, generous, and prosocial decisions via the amygdala.

Life Science Databases/Wikimedia Comons
Amygdala in red. 
Source: Life Science Databases/Wikimedia Comons

The December 2015 study, “Neural Mechanisms of Social Decision-Making in the Primate Amygdala,” was published in the journal Proceedings of the National Academy of Sciences.

According to the researchers, the amygdala plays an important role in both our decision-making processes and our social behaviors. Every social decision we make requires an evaluation of the potential benefits and cost of our actions to ourselves and others. It appears that our amygdala have the ability to send signals about both social reward and potential punishment

In a press release, lead author Michael Platt of the University of Pennsylvania described his team's research saying,

“What we're trying to do is both identify and understand the basic brain mechanism that allows us to be kind to each other and to respond to the experiences of other individuals. We're also trying to use that knowledge to evaluate potential therapies that could improve the function of these neural circuits, especially for those who have difficulty connecting with others. Such a link could have implications for people with autism, schizophrenia or anxiety-related disorders.”

To advance understanding of the amygdala, Platt and his team studied the social behavior of rhesus macaques. The researchers developed a way to observe how these primates made beneficial prosocial decisions based on the ‘reward-donation’ of a task. While they were watching the monkeys' behavior, Platt and his colleagues were able to record the neural activity of their amygdala.

The team was looking specifically for correlations between what was happening in the brain of the monkeys as it related to their social behaviors. The researchers discovered that neural activity in the amygdala directly mirrored the value placed upon generosity, kindness, and charitable behavior. The scientists could actually predict when certain monkeys were going to be be generous and charitable based on their neural responses.

Oxytocin Can Influence Charitable Behavior via the Amygdala

The researchers also discovered that when oxytocin was introduced into a specific region of the amygdala, prosocial behaviors increased instantaneously. Oxytocin is a complex hormone that is strongly linked to social bonds within many species, but also has the potential to create machiavellian behaviors.

Though this new research is in its earliest phases, it does show promise for identifying ways that targeting oxytocin treatments in specific regions of the amygdala could help people with autism spectrum disorders (ASD) better interpret and understand social cues. 

Oxytocin in the basolateral amygdala (BLA) neurons particularly increased both the frequency of prosocial decisions and attention to recipients for context-specific prosocial decisions. These findings support the hypothesis that oxytocin regulates social behavior, in part, via amygdala neuromodulation. These new findings demonstrate both the neurophysiological and neuroendocrinological connection between the amygdala and various types of social decisions.

Conclusion: Amygdala Research Holds Clues for Increasing Prosocial Behaviors

Delivering oxytocin into basolateral amygdala of monkeys enhances both prosocial tendencies and attention to the recipients of prosocial decisions. Although more research is necessary before drawing conclusions about human applications for these findings, this is a promising discovery for identifying new possible treatments for optimizing loving-kindness, magnanimity, and charitable behaviors. . . . Especially in people who are neurobiologically inclined to be aggressive, hateful, and antisocial. 

Platt concluded, "Our findings endorse the amygdala as a critical neural nexus regulating social decisions. Just like humans, the stronger these bonds the monkeys have, the more successful they are. Monkeys with more friends and better friends live longer and have more offspring.”

To read more on this topic, check out my Psychology Today blog posts:

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