Some evidence suggests that when fathers do take on the role of being the main caregiver, they adopt behaviours more typical of mothers. For example, Field filmed 4-month-old-babies in face to face interaction with primary caregiver mother, secondary caregivers, father and primary caregiver fathers. They found that primary caregiver father spent more time smiling, imitating, and holding infants than secondary caregiver fathers. Smiling, imitating, and holding babies, are all part of reciprocity and interactional synchrony as the process of attachment. Showing it fathers have the potential to be more emotional focus primary attachment figures- they can provide the responsiveness required for close emotional attachment but perhaps only expresses when given the role of primary caregiver.