Attachment exerted an invisible but powerful pull on the child, just as heavenly bodies are connected by gravitational forces. But unlike gravity, attachment makes its presence known by a negative inverse square law: the further the attached person is from their secure base, the greater the pull of attachment. The 'elastic band' which constitutes the attachment bond is slack and imperceptible in the presence of a secure base. If the secure base becomes unreliable or the limits of exploration are reached, the bond tugs at the heartstrings.
Jeremy Holmes, John Bowlby and Attachment Theory
attachment-theory, psychology, secure-base