Loneliness hurts. It is psychologically【C1】_____and so physically unhealthy that being lonely【C2】__the likeli-hood of an earlier death by 26 percent.【C3】__the feeling may serve a purpose. Scientists【C4】__that it hurts so much because, like hunger and thirst, loneliness acts as a【C5】__alarm bell. The ache of it drives us to seek out social【C6】__just as hunger pangs urge us to eat. The idea is【C7】_____satisfying, yet it has long proved difficult to test in humans.

On March 26, researchers at the Massachusetts Institute of Technology posted a【C8】_____report on bio-Rxv. It was the first study in humans to show that both loneliness and hunger【C9】__signals deep in a part of the brain that【C10】__very basic impulses for reward and motivation. The findings point【C11】_____one telling conclusion: our need to connect is apparently as fundamental as our need to eat.

The extraordinary scientific timing of the paper’s release—just as tens of millions of people were suddenly starved for contact in the special period of 2020—was【C12】_____intentional. When they began the work three years ago, neuroscientists Livia Tomova and Rebecca Saxe and their colleagues wanted to demonstrate how loneliness operates in the brain. They were【C13】_____by similar research in animals and by the pioneering loneliness studies.

The【C14】_____, which has not yet been peer-reviewed, describes a【C15】__designed experiment using functional magnetic resonance imaging (fMRI) to compare brain responses【C16】__loneliness and hunger.【C17】__a baseline brain scan, 40 adult participants【C18】__two 10-hour sessions: one in which they were【C19】__food and another where they were denied social contact. The sessions served as control conditions for each other. “They show a really strong wanting response,” Tomova says. “It’s quite established that this【C20】_____the dopaminergic response.”

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