Affect attunement, attachment, temperament, and zygosity: a twin study.

A twin study examines the relationship of affect attunement to four factors of development: zygosity, temperament, attachment, and twin preference. Affect attunement occurs when an infant expresses affect and a mother responds cross-modally, matching duration, intensity, and rhythm. A sample of 16, same sex, healthy twins (8 MZ, 8 DZ) and their mothers were recruited at 10 to 12 months of age. Monozygous twins attuned at more similar rates than dizygous twins. There was no relationship between attunement, attachment, and temperament, nor between affect signal rate and attunement. Five of eight mothers expressed a twin preference. Eleven of the 16 infants were classified securely attached. Affect attunement is discussed as a measure of the complementarity between an infant's affect signaling rate and a mother's contingent responsiveness.