Why Do People Want to Meet Someone? The Brain Mechanism That Feels Loneliness as "Hunger"

A mouse that has spent several days alone reunites with its companions. It squeaks in a high-pitched voice, follows the other, and crawls under its body. To the human eye, it appears as if it is trying to hug.

Describing this behavior as "because it was lonely" might seem like projecting human emotions onto animals. However, in recent years, neuroscientists have been exploring the possibility that the drive to seek social contact is embedded in the mechanisms that maintain life in a stable state, much like hunger or thirst.

In other words, we don't meet people just for pleasure. When the brain determines there is a "lack of connection," the desire to meet someone, hear a voice, or touch may arise.

Loneliness Cannot Be Measured by "Numbers"

When considering loneliness, the first distinction to make is between "being alone" and "feeling lonely."

Some people feel lonely in a bustling party, while others feel content even when alone in a quiet room. The amount and form of interaction required vary by animal species, and among humans, there are significant individual differences. Some maintain their well-being by talking to many people daily, while others need deep relationships with a few people and sufficient alone time.

Therefore, considering the solution to loneliness as simply "increasing friends" is too simplistic. What matters is the extent of the gap between the connections a person needs and the connections they actually have.

The concept of "social homeostasis" is gaining attention as a mechanism to measure and adjust this gap. Just as the body shivers when the temperature drops and sweats when it rises, the brain detects a lack or excess of social contact and changes behavior accordingly. It's as if there is a social thermometer in the brain.

After 10 Hours of Isolation, People Crave "People"

In a study involving humans, participants were isolated from contact with others for 10 hours. After isolation, participants reported a strong desire for social interaction.

Furthermore, when examining brain images, a part of the midbrain reacted when participants viewed photos of people enjoying social interactions. This reaction was similar to the response of people who had been deprived of food when they saw pictures of food. This area includes the dopamine system, which is involved in motivation, reward, and desire.

These results do not prove that "loneliness is exactly the same as hunger." However, the fact that the brain deprived of social contact shows a "craving" response similar to when deprived of food suggests that connection with others may not be merely a hobby or luxury.

We don't call hunger a lack of willpower. Similarly, feeling lonely should not be dismissed as a character flaw or mental weakness. If loneliness is seen as a signal from the body and brain indicating "something necessary is lacking," it can be treated as information for adjusting one's life rather than a source of shame or self-denial.

"Isolation" and "Reunion" Circuits Found in Mouse Brains

In a study published in 2025, adult female mice were isolated for several days and briefly reunited with their sisters while observing brain activity.

Researchers focused on the hypothalamus, which is involved in regulating hunger, thirst, sleep, and other functions. There, they identified groups of neurons that were active during isolation and calmed during reunion, and conversely, neurons that were active during reunion.

When the isolation-side cells were artificially stimulated, the mice avoided the place associated with that stimulation. On the other hand, when the reunion-side cells were stimulated, the mice preferred that place. These results suggest that isolation is processed as an unpleasant state and reunion as a reward.

Additionally, the longer the isolation, the more time the mice spent following, sniffing, and squeaking at their companions after reunion. Just as being deprived of water leads to drinking more and skipping meals leads to eating more, it seems there is a "rebound" effect to make up for the lack of social contact.

However, the behavior of mice cannot be directly applied to human loneliness. Human relationships are intricately influenced by language, memory, culture, status, and past experiences of hurt. Nonetheless, the possibility that the ancient brain mechanisms regulating isolation and reunion are common among mammals provides a significant clue for considering loneliness as a biological issue.

Why "Touch" Is Special

Particularly striking in the original article is an experiment investigating how mice confirm the presence of their companions.

Even mice that lost their sight reacted to isolation. When placed in the same cage with a perforated partition that allowed voices and smells to pass through but not sight, it was not considered sufficient contact. What mattered was the ability to directly touch the body of the other.

Isolated mice preferred passages covered with soft cloth over hard ones. Soft pressure and skin stimulation may help alleviate contact deficiency, even if not completely.

In humans, slow stroking, hugs, a hand on the back, or massage-like pressure are processed through unique sensory pathways. This is why the feeling that cannot be filled by exchanging numerous messages might be slightly eased by a short handshake or a hug with family.

However, it is dangerous to speak of touch as a panacea. Some people are uncomfortable with being touched. The distance that feels safe varies depending on past experiences, culture, and relationships. What matters is not increasing the amount of contact but choosing touch that is consensual and feels safe.

When Isolation Prolongs, You Want to Meet but Can't

In short-term isolation, many animals strongly seek out their companions. However, when isolation becomes prolonged, the same reaction does not necessarily continue.

Some studies have shown that male mice isolated for long periods become avoidant or aggressive rather than sociable upon reunion. In humans, after extreme isolation such as long-term solitary confinement, a state may occur where one seeks contact with others but simultaneously fears it.

This is also why advising lonely people to "just go out" or "just talk to someone" is insufficient. The longer isolation continues, the more one loses confidence in conversation, anticipates rejection, and feels strong fatigue or anxiety in crowded places. A contradiction arises where the brain, needing connection, avoids contact to protect itself.

Therefore, the entry point to recovery is not necessarily large gatherings. Going to a familiar store, taking a walk at a set time, making voice calls with someone you talked to online, or regularly meeting the same people in a class may be more helpful as predictable and less burdensome contacts.

Empathy Spread on SNS—"Connected but Unfulfilled"

In a public post on LinkedIn introducing this study, it was suggested that "social contact may not be an emotional reward but a biological necessity." It was also shared that a distinction should be made between "being satisfied alone" and "suffering from isolation."

On Reddit, more relatable reactions were prominent: "Even if connected with many people through SNS or messages, loneliness doesn't disappear without deep relationships," "Online can be a chance to meet, but it doesn't necessarily nurture the relationship itself," and "More important than the number of connections is spending time in the same space and intimacy."

In threads discussing the lack of touch, voices were raised not only about romantic or sexual contact but also about "not having hugs with friends," "not having anyone put a hand on your shoulder," and "clinical massage is different from affectionate contact."

As countermeasures, experiences such as asking family or friends for hugs, living with pets, using massage services, participating in social dance or team activities, and using heavy blankets were shared.

On the other hand, realistic barriers were also discussed, such as "pets and massages cost money," "it's difficult to ask for a hug from someone you're not close to," and "not having the energy to meet people." Loneliness cannot be solved by individual effort alone. It is also influenced by social design, including economic conditions, work styles, living environments, transportation, local community spaces, and safety.

These posts are not public opinion surveys but merely experiences of some SNS users. Nonetheless, they convey that the "social desires" indicated by research are experienced in daily life as "the loneliness of not getting a reply," "the pain of not being touched by anyone," and "the emptiness after closing the screen."

SNS Is Not the Enemy, But "Just Watching" May Not Be Enough

There is no simple conclusion about whether SNS creates or alleviates loneliness. Some studies suggest that those who spend more time on SNS feel lonelier, but there is also the possibility that people use SNS longer because they are lonely, so the causal relationship needs careful consideration.

What matters is not just the screen time but how it is used. If you endlessly look at acquaintances' posts and only compare yourself, the lack of connection may be emphasized. On the other hand, using it to contact specific people, talk about worries, and connect to calls or face-to-face meetings can be an entry point to alleviating isolation.

SNS should be used not as a "substitute for relationships" but as a "pathway to relationships." Sending "How have you been?" to one person is better than pressing "like" a hundred times. Instead of continuously looking at photos of strangers having fun, regularly participating in small gatherings with the same hobby is more important. Turning connections into reciprocal interactions is key.

What We Need Is Not Sociability but "Adjustable Connections"

Even if social contact is a basic need, not everyone needs to be extroverted. What is necessary is knowing your social thermometer and being able to adjust according to deficiency or excess.

If you feel better after alone time, that time is not isolation but recovery. On the other hand, if being alone narrows your thoughts, makes you unable to sleep, leaves you unmotivated, and you can't contact anyone even though you want to, it might be a signal of a lack of connection.

The adjustments you can make in daily life can be small. Meet the same person regularly. Make short phone calls. Engage in non-work-related small talk. Have a place where you can exchange greetings. Share a meal with someone. If both feel comfortable, cherish handshakes, hugs, or light touches on the shoulder.

Rather than a large network, relationships where you can predict "we'll meet again" can create a sense of security.

What loneliness research teaches us is not that humans can't do anything alone. It is that the very power to live independently is supported by safe connections with others.

Needing someone is not a weakness. Just as we eat when hungry and sleep when tired, our brains sometimes seek voices, expressions, conversations, and body warmth. Creating a society where we can notice and respond to these signals without shame might be what is needed in the age of loneliness.

Source URL

"Why we crave company" published by Local News 8 via Stacker. The article that served as the basis for this piece.
https://localnews8.com/stacker-wellness/2026/07/14/why-we-crave-company/

The original article's source. A scientific explanation by Knowable Magazine, referencing social homeostasis, mouse reunion behavior, and the importance of touch.
https://knowablemagazine.org/content/article/mind/2026/why-we-crave-social-interaction

A study in Nature Neuroscience that examined midbrain activity similar to the response when seeing food when hungry, after isolating humans for 10 hours and investigating the craving for social interaction.
https://www.nature.com/articles/s41593-020-00742-z

A 2025 study published in Nature showing different hypothalamic neural circuits active during isolation and reunion.
https://www.nature.com/articles/s41586-025-08617-8

A review in the Annual Review of Neuroscience organizing social desires and physiological needs like hunger and thirst from the perspective of neural circuits and homeostasis.
https://www.annualreviews.org/content/journals/10.1146/annurev-neuro-112723-025633

A LinkedIn public post introducing "Loneliness may be akin to hunger" and "Social contact may not be a choice but a basic necessity."
https://www.linkedin.com/posts/dr-todd-boudreau-76841a6_why-we-crave-company-activity-7470768741115637761-lqSA

A LinkedIn public post pointing out the difference between being satisfied alone and suffering from loneliness.
https://www.linkedin.com/posts/pamcowley_why-we-crave-company-activity-7472402375509475329-O0Zy

A Reddit thread discussing the difference between online connections and deep relationships or face-to-face interactions.
https://www.reddit.com/r/NoStupidQuestions/comments/1rpvrn0/why_do_people_seems_more_lonelier_than_ever_when/

A Reddit thread discussing the realization of touch deprivation, hugs, pets, massages, social activities, costs, and psychological barriers.
https://www.reddit.com/r/datingoverforty/comments/1qk5f1h/touch_starvation_dealing_with_life_without/

A study examining the relationship between SNS use and loneliness. The relationship is influenced by usage and motivation, and causality cannot be determined due to the cross-sectional nature of the study.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12220285/