Why do people who experience loneliness process the world differently?

A recent study led by a scholar at the USC Dornsife College of Letters, Arts and Sciences, and published in Psychological Science, suggests that, when it comes to how the brain processes information, people who are lonely are also homogeneous in the way they process the world in their own idiosyncratic way.

Research shows that loneliness is highly detrimental to well-being, and often accompanied by anxious and self-reported feelings of not being understood by others. According to a recent report conducted by the United States Surgeon General's office due to the growing number of adults suffering from this condition, loneliness is now officially referred to as a public health crisis. Even prior to the COVID-19 pandemic, thousands of U.S. adults reported their feelings of loneliness.

Hoping to better understand feelings of disconnection and being misunderstood, Elisa Baek, assistant professor of psychology at USC Dornsife, and her team used functional magnetic resonance imaging (fMRI) to examine the brains of 66 first-year college students whilst they watched a series of videos clips. For analysis, the videos featured a wide variety of scenarios and topics such as sentimental music videos, party scenes and sporting events.

Before the scan, all participants, who were aged between 18 and 21, were asked to complete the University of California (UCLA) Loneliness Scale, a survey for measuring a person's subjective feelings of loneliness and social isolation. Based on the results, the researchers separated the participants into two groups: lonely and "non-lonely".

When comparing the brain imaging between both groups, the researchers discovered that the lonelier individuals exhibited more idiosyncratic brain processing than their non-lonely counterparts.

This discovery is significant as it reveals that neural similarity, which refers to how similar the brain activity patterns of different individuals are, is linked to a shared understanding of the world. A shared understanding of the world is vital for establishing social connections. People who suffer from loneliness are not only less similar to society's norm of processing the world, but each lonely person also differs in unique ways.

Baek commented on the study, saying: "It was surprising to find that lonely people were even less similar to each other. The fact that they don't find commonality with lonely or non-lonely people makes achieving social connection even more difficult for them."

"The 'Anna Karenina principle' is a fitting description of lonely people, as they experience loneliness in an idiosyncratic way, not in a universally relatable way," Baek continued, referring to the fictional book by Russian writer and philosopher, Leo Tolstoy.

The researchers observed that individuals with significantly high levels of loneliness, regardless of how many friends and social connections they had, were considered to be more likely to have idiosyncratic brain responses. Evidently, this raises the possibility that being surrounded by people who see the world differently from oneself may be a risk factor for loneliness.

Going forward, Baek states her keen interest in examining people who have friends and are socially active but still feel lonely. Additionally, the researchers are examining particular situations that lonely individuals process differently from others.