Winfried Rothermel / AP

People are often unwilling to admit being lonely. They may be ashamed of feeling that way, and want to be seen positively by friends and family—better that they imagine you to be a sparkling social butterfly than a cocooned Netflix-watcher who just wishes they were out fluttering with friends. Even in scientific studies there’s something called the “social desirability bias,” where participants are more likely to give answers that they think people want to hear, so that others will like them.

The saddest part is, people who hide their loneliness may have good reason for doing so—one study shows that lonely people are seen more negatively by new acquaintances. But the loved ones of a lonely person could play a big role in helping them feel better, and ameliorating the serious health risks of social isolation.

The question is, can people even tell when others are feeling lonely? Research has shown that people can do a pretty good job identifying personality traits like extraversion and agreeableness in others, even others they don’t know that well, but loneliness is by nature more interior than personality. A new study published in the Journal of Research in Personality investigates the loneliness question and comes away with the answer: Sort of. And it depends on your relationship to the person.

A group of German researchers, from the University of Cologne, Free University of Berlin, and RWTH Aachen, looked at online survey data from 463 young adults who self-reported their feelings of loneliness and life satisfaction. Then, using emails provided by the participants, the researchers contacted these people’s friends, parents, and romantic partners (if they had any), and had them rate their person’s loneliness and life satisfaction, too.

For the most part, others’ assessments of a person’s loneliness tracked with the person’s self-report. “In our study, the convergence between self-ratings and informant ratings of loneliness was substantial,” the study reads. (The same was true for life satisfaction.)

Romantic partners were better than both parents and friends at detecting how lonely or satisfied a person was, probably due to the (often) more intimate nature of that relationship. Friends and parents were both more likely to positively skew their ratings of a person. Interestingly, while partner ratings were very similar to both friend and parent ratings, the friend and parent ratings were not similar to each other. “These findings indicate that when making judgments of loneliness and life satisfaction, parents utilize information that is also available to the partners, but not to the friends,” the researchers write. “Similarly, friends utilize information that is also available to the partners, but not to the parents.” People share things with their friends they wouldn’t share with their parents and vice versa, but it seems that their partners learn about all parts of their lives.

On the research side, these results mean that scientists could use friends, family, and romantic partners’ reports of people’s loneliness to corroborate their self-reports. But on the more personal side, if you suspect that someone you love is feeling lonely, even if they haven’t said so, chances are you’re on to something.

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