A first-year college student lies still inside an fMRI scanner and watches a set of short video clips. Another student watches the same clips in the same machine. You might expect their brains to respond in broadly similar ways. A new study in Psychological Science suggests that this is less true for students who feel lonely.
The study looked at 66 first-year university students. Each student watched the same naturalistic videos during functional MRI scanning. After the scan, they completed the UCLA Loneliness Scale, a widely used measure of perceived loneliness. The researchers then compared how closely each student’s brain activity matched the activity of other students while they watched the clips.
The main result was clear. Students with higher loneliness scores showed less shared patterns of brain activity. Their neural responses were more idiosyncratic.
That word can sound technical. In plain English, it means more personal and less like everyone else’s. If most people’s brains reacted in one similar pattern while watching a clip, lonelier participants were more likely to show a pattern that stood apart from the group.
The team did not ask participants to solve puzzles or answer social questions in the scanner. They used everyday-style video clips instead. That matters because social life rarely arrives as a neat lab task. People move through stories, jokes, awkward moments and shifting signals from other people. The study tried to capture that messier kind of real-world processing.
To measure similarity, the researchers divided the brain into 214 regions and tracked activity over time in each one. They then compared those time series across pairs of participants. This method is called intersubject correlation. Higher correlation means two people’s brains responded in more similar ways moment by moment. Lower correlation means their responses drifted apart.
Loneliness was linked to lower similarity in several regions tied to social understanding and internal interpretation. These included parts of the default mode network, a set of brain regions often involved in thinking about other people, making sense of events and building subjective meaning. The effect also appeared in parts of the striatum, including the nucleus accumbens, caudate and pallidum, which are linked to motivation and reward.
This does not mean lonely people are wrong in how they see the world. The study does not support that claim. It suggests something narrower. People who feel lonely may be less aligned with the dominant mental patterns of the people around them, even when everyone is looking at the same thing.
The pattern held up after the researchers controlled for several other factors. They adjusted for demographic similarity, objective social isolation and whether participants were friends with each other. That point matters. A person could still have friends and yet show brain responses that were less in sync with peers overall. Loneliness is not the same thing as being alone. It is a subjective state. You can be socially connected on paper and still feel out of step.
The authors were careful with their language. The study does not show that loneliness causes these neural differences. The arrow could point the other way. People who process social information in less shared ways might be more likely to feel misunderstood. It is also possible that the relationship runs both ways over time. The data cannot settle that.
There are other limits too. The sample was modest and all participants were first-year university students. That is a specific life stage. The transition into college often brings social stress, new routines and unstable friendships. The same pattern may not look identical in older adults, teenagers or people in different cultures. fMRI studies also measure blood-flow changes, not thoughts themselves. The scans can show that people differ in timing and pattern, but they cannot tell us exactly what any one participant was thinking in a given second.
Even with those limits, the paper arrives at an important moment. Loneliness is now treated as more than a private feeling. Public health agencies have started to frame weak social connection as a population-level problem. In 2023, the U.S. Surgeon General warned that loneliness and isolation carry serious health risks and deserve broad policy attention. Studies like this one add a new layer to that discussion. They suggest that loneliness may shape the way people interpret the social world around them, not just how often they see other people.
That idea has weight. Shared life depends in part on shared meaning. Friends laugh at the same scene. Coworkers read the same room. Strangers find common ground in a story, a news event or a cultural reference. If lonely people are less likely to process those signals in sync with others, that could help explain why loneliness often feels like being unseen or not fully understood.
The study does not offer a neat conclusion, and that is part of its value. It moves the conversation away from the idea that loneliness is only about the number of people in someone’s life. It points instead to shared perception. Two people can sit side by side, watch the same moment and still experience it in meaningfully different ways. For some lonely individuals, that gap may be part of the problem.
References
Baek, E. C., Hyon, R., López, K., Du, M., Porter, M. A., & Parkinson, C. (2023). Lonely individuals process the world in idiosyncratic ways. Psychological Science, 34(6), 683-695.
Broom, T. W., Iyer, S., Courtney, A. L., & Meyer, M. L. (2024). Loneliness corresponds with neural representations and language use that deviate from shared cultural perceptions. Communications Psychology, 2, Article 40.
Office of the Surgeon General. (2023). Our epidemic of loneliness and isolation: The U.S. Surgeon General’s advisory on the healing effects of social connection and community. U.S. Department of Health and Human Services.
