Perhaps this is the most famous of the concepts created by D. W. Winnicott (1896-1971). The transitional object is a soft toy or a blanket the small child carries with him and uses as a comforter especially before going to sleep. The transitional object starts acquiring importance when the child emerges from the symbiotic relationship, begins to distinguish between me and not me, between himself and his mother. The transitional object represents both. It has mother's smell, but it stays with him. It remains under his control, while mother is absent. Thus, the transitional object allows the child to increase his independence. By extension any personal possession can function as a transitional object. It can be anything material, but it can be also an ideology, a grouping of people who hold the same believes.
See also ATTACHMENT THEORY, SEPARATION, SYMBIOSIS