The stability of eight attachment behaviors was investigated in two samples of infants. One sample observed at 10 and 14 months of age, the other sample at 14 and 18 months. For each testing period, the infants were observed during two sessions: (a) in the presence of the mother; and (b) before, during, and after a brief separation experience. Correlational analyses were performed to assess within-session stability, day-to-day stability, and stability across a 4-month period. There was little stability of any kind for visual regard and vocalizing to the mother or in crying and three behaviors indicating orientation to the locus of the mother's disappearance. In contrast, both short- and long-term stability were found for touching and proximity to the mother. The results point to the hypothesis that attachment behaviors do not form a uniformly stable system in 10-, 14-, and 18-month-old infants. (Author/MG)