Nurtured to follow the crowd: A twin study on conformity

Why are some of us easily affected by the majority’s action whereas others frequently make unique choices? In this behavioral genetic study on conformity, we designed a social episode to investigate the genetic and environmental origin of individual differences in conforming behavior during psychosocial development. Specifically, 107 monozygotic (MZ) and 74 dizygotic (DZ) twin pairs (age 7–19) were asked to choose a pen from a group of pens either with the majority color or with the minority color. We found that the resemblance between MZ twins in selecting the pen with the majority color was not significantly higher than that between DZ twins, suggesting that individual differences in conformity are due almost exclusively to the environment. Moreover, biometric model fitting revealed that the shared environmental component played a sizable role in shaping individuals’ conforming behavior, and the influence increased with age (from 16% to 26%). Taken together, our study suggests that the common family and cultural environment has important ramifications for conformity.