Extensive non-maternal childcare plays an important role in children’s development. This
study examined a potential coping mechanism for dealing with daily separation from
caregivers involved in childcare experience – children’s development of attachments toward
inanimate objects. We employed the twin design to estimate relative environmental and
genetic contributions to the presence of object attachment, and assess whether childcare
explains some of the environmental variation in this developmental phenomenon. Mothers
reported about 1122 3-year-old twin pairs. Variation in object attachment was accounted for
by heritability (48%) and shared environment (48%), with childcare quantity accounting
for 2.2% of the shared environment effect. Children who spent half-days in childcare
were significantly less likely to attach to objects relative to children who attended full-day
childcare.