The Group
Strangers with no shared past form, within an hour, an entity with moods and purposes that none of them holds.
What was observed
In 1942 Wilfred Bion, assigned to the training wing of Northfield Military Hospital, treated the wing as a whole rather than its members one by one. At the Tavistock after the war he led groups of civilians with no agenda, addressing his interpretations to the group. In Experiences in Groups (1961) he reported that a group left without a task behaves as a single entity, organized around a shared, unspoken basic assumption about what it is for: dependency on an idealized leader, fight-flight against an enemy, or pairing in expectation of a saviour who must never arrive.
The assumptions are held by no one. They are in the group's behaviour, and members act on them against their own judgement; the leader feels the pull as strongly as anyone. Through what Bion called valency, the group finds among its members those whose readiness fits the role it needs. The role is the group's, and it found this person because of something already theirs: the structure Bowen found in the identified patient. When the occupant leaves, the position is filled again.
S. H. Foulkes, who ran groups at Northfield after Bion, put it more bluntly: the individual is an abstraction, a node in a network of relationships he called the matrix. He described resonance, a single communication taken up at different depths across the group, and the location of disturbance: a symptom appearing in one member is located there by the group, which makes the member its site, not its source.
Later writers extended the matrix outward. Earl Hopper described a social unconscious, the unprocessed history of a society carried into every group formed within it, and added a fourth basic assumption, incohesion, characteristic of traumatized groups. René Kaës described unconscious alliances, including denial pacts by which members agree, without ever speaking of it, about what the group will not know.
What it shows
The family could be said to behave as a unit because of its ties. The group removes that explanation. The same organization appears among strangers, the positions outlast those who occupy them, and the whole is embedded in larger grounds its members carry without having lived them. The ties are not what does it.