Twenty-four children under three years of age were observed singly in a strange play room, with or without the mother or a familiar adult. Security was assumed to be evidenced by adaptive behavior directed toward objects in the situation, and insecurity by emotional behavior and autistic gestures. Emotional and adaptive types of behavior correlated negatively (-.72 to -.91). Ten patterns of behavior were used to scale the degree of insecurity, which appeared to decrease with familiarity (repeated visits) and in the presence of the familiar adult. Insecurity is interpreted in terms of unfamiliarity of the situation and the child's feeling of power. Topological diagrams are presented and wartime implications suggested. (PsycINFO Database Record (c) 2006 APA, all rights reserved)