Self-conscious Shyness: Growth during Toddlerhood, Strong Role of Genetics, and No Prediction from Fearful Shyness

Fearful and self‐conscious subtypes of shyness have received little attention in the empirical literature. Study aims included the following: (1) determining whether fearful shyness predicted self‐conscious shyness, (2) describing development of self‐conscious shyness, and (3) examining genetic and environmental contributions to fearful and self‐conscious shyness. Observed self‐conscious shyness was examined at 19, 22, 25, and 28 months in same‐sex twins (MZ = 102, DZ = 111, missing zygosity = 3 pairs). Self‐conscious shyness increased across toddlerhood, but onset was earlier than predicted by theory. Fearful shyness (observed [6 and 12 months] and parents’ reports [12 and 22 months]) was not predictive of self‐conscious shyness. Independent genetic factors made strong contributions to parent‐reported (but not observed) fearful shyness (additive genetic influence = .69 and .72 at 12 and 22 months, respectively) and self‐conscious shyness (additive genetic influence = .90 for the growth model intercept). Results encourage future investigation of patterns of change and inter‐relations in shyness subtypes.