A comparison of the anterior prefrontal cortex and caudate nucleus in the brains of adolescents and adults. Credit: neuroimage/iStock

A half-century ago, psychologists observed that toddlers had a relationship to the world that was undeveloped, but by age 3, we were already taking sides on social conflicts and making judgments, and socializing with strangers would soon be routine. Today, the most common question we ask is “what are your friends’ Facebook interests?”

What happens to our brains when we see social media posts? The short answer is that they profoundly affect our minds and, in some cases, even lead to brain changes.

When people post Facebook messages, images, videos or links, they activate neurons in a part of the brain that consists of two tissue-packing cylinders, known as the posterior cingulate and caudate nucleus. This part of the brain receives feedback from other parts of the brain, and acts as a hub for nerve communication. On the basis of facial expressions, we are constantly motivated to develop a stronger relationship with other people through various human and virtual social networks.

At the same time, since these feedback loops are so strongly tied to our cognitive plasticity, this kind of software functions to act as an overall boundary to the default mode of behavior—behavior in which, as biochemist Walter Draper claimed, we are primarily motivated by our emotions rather than intellect.

This paradoxical state, in which humans and computers appear to interact constantly and creatively, appears to exist for a fundamental reason: Social feedback loops are self-regulating mechanisms that include social media want immediate rewards.

The effect is often described as a “feedback loop that makes a statement to itself.” And the insight that we sometimes have less than present-person capacity to empathize with others with the power to change our emotional state is well known, though recent research has widened our understanding of the neural mechanisms that give shape to this instinctive judgment.

For example, we recently saw that optogenetics can be used to allow scientists to access the deeper circuitry of the cortex to study how conscious attention activates the effect of feedback loops. This study, which shows for the first time how the brain monitors the system by which people are motivated to share social media content, could help scientists understand how people use the internet. The instinctive reaction is comparable to that of other cells in the brain known as complex opsins, which are involved in daydreaming, visual processing and perceptual processes.

Since social feedback loops are powerful self-regulating mechanisms, social media posts could play a role in rewiring the brain, in the same way that dopamine helps with hunger and cocaine seems to help get things done. At a basic level, we view this as a good thing. But the ethical question we face is about whether you have the right to rewire our brain in this way.

Illustration: Waldo Ceplo/Creative Commons

A recent study, funded by the National Institutes of Health, showed that Facebook users are hooked to the moment when they receive a boost in their feed activity, and this is linked to subsequent changes in their brain activity. In a series of brain scans, the study’s authors correlated the neural response to Facebook posts with the emotional arousal of the subjects.

In a paper published in November in JAMA, the researchers identified a specific brain mechanism in the posterior cingulate that is activated when a person receives a positive response from the world around them, and that suppresses the response when a negative response occurs. The authors suggested that this mechanism of gut-driven stimuli is a response that is “hugging” from higher brain functions.

So if I reach out to you on Facebook, it could be a way to exercise the feedback loop to trigger a pleasure response in me and a reduction in the fear response that occurs when I have a negative experience in the world around me.

On the other hand, if I experience a negative post, there is the potential for activation of another system, which is associated with more of a reactive response. On the broader basis, should we feel that we can have social media for their utility when our brains are engaged in feedback loops that are operating in this way?