Attachment theory, developed by Bowlby and extended by Ainsworth, maps how the quality of early relational experience shapes the nervous system's expectations about safety, connection, and self-worth. The four attachment styles — secure, anxious, avoidant, disorganized — are not fixed destinies but probabilistic patterns that persist until interrupted by new relational experience. Understanding one's attachment history is not blame but orientation: it locates the source of the patterns so that change becomes possible.
Each step builds on the last.