Imagine someone who moves to a new city for a good job. The apartment is fine, the work is interesting, and the commute is short. Then one Sunday evening it occurs to them that nobody in the city would notice if they did not come home. Nothing is wrong, exactly. Something is missing, and it is hard to name.
Psychologists have a name for the thing that might be missing. They call it the need to belong, and one of the most cited attempts to define it is a 1995 review by Roy Baumeister and Mark Leary in Psychological Bulletin.
A hypothesis, not a slogan
Baumeister and Leary did not simply say that people like company. They proposed a belongingness hypothesis: humans have a strong drive to form and keep lasting, mostly positive relationships, and when that drive goes unmet, health, emotion, and thinking can suffer. They argued the drive is powerful and pervasive, and then they went through the existing research to see whether the pattern held up.
Their account is more specific than it sounds. Two conditions have to be met together, according to the review. Both are shown below.
- Regular contact. Frequent interaction with a small number of people, ideally pleasant and mostly free of conflict.
- A stable frame. The contact happens inside a lasting relationship in which each person believes the other cares about their welfare.
- Both, not either. Lots of contact without a bond is not expected to satisfy the need, and neither is a bond with almost no contact.
That second condition explains the new-city example. The person might see coworkers every day, which is contact, and still lack anyone for whom they matter in a continuing way.
What the evidence looked like
The review pulled together several kinds of observation.
- Bonds form easily. People attach to others and form groups under surprisingly thin conditions, including arbitrary assignment to a group, shared hardship, and repeated proximity.
- Bonds resist ending. People work to keep relationships going, with greetings, goodbyes, and promises to stay in touch, and the end of a relationship usually brings distress, even when the relationship was a poor one.
- Emotion follows connection. New bonds tend to bring positive feelings, while threatened or lost bonds are linked with anxiety, grief, jealousy, and loneliness.
- Lacking bonds goes with worse outcomes. Across the studies they surveyed, people without close ties showed higher rates of physical and mental health problems.
Belonging is not the same as being surrounded
Baumeister and Leary noted that loneliness tracks perceived isolation more than the raw amount of contact. That is why a person can feel unmoored at a party and settled in a quiet house. Researchers separate the objective side, having few contacts, from the subjective side, feeling that the connection you have falls short of the connection you want. The article on why loneliness can exist in a crowded world follows that distinction further.
Belonging also is not limited to romantic partners or best friends. A team, a congregation, a choir, or a regular table at a neighborhood restaurant can supply some of what the hypothesis describes, which is one reason rituals such as shared meals keep appearing across cultures. Who counts as “a few others” varies a great deal between societies, and much of the classic psychology literature has drawn on participants from Western, educated, industrialized settings, so the hypothesis is better tested in some places than others.
Two predictions worth knowing
The authors made two further predictions that are easy to misread. The first is substitutability: a new relationship can partly fill the place of a lost one, although building real closeness takes time. The second is satiation: once a person has a basic level of connection, extra bonds should add less. Baumeister and Leary treated both as predictions supported mainly by indirect evidence, not as settled laws. In everyday terms, it suggests that the goal is not a bigger network but enough of the right kind of bond.
Why this matters beyond the lab
If belonging is a core motivation, a lot of ordinary behavior reads differently. Joining a club, staying in a hard job because of the people, and feeling stung by being left off a group chat are all signs that the drive is working as described. It also suggests why shared stories and group traditions carry so much weight: they tell people who “we” are.
It does not mean everyone needs the same amount of company. Introverts and extroverts differ in how much contact they enjoy, and the hypothesis is about the quality of a few bonds more than the quantity of social time. And it does not mean that feeling disconnected is a personal failing. If persistent disconnection is weighing on you, a doctor, counselor, or other mental health professional can help, and this article is educational, not medical advice.
