During puberty and the transition to adulthood, hormones and brain changes drive an intense desire for dispersal, leading adolescents to move away from primary caregivers and spend more time with peers.

“there's an intense desire on the part of the child to get further and further away from primary caregivers mostly there's a desire to start spending more time with friends more time with peers and less time with adults so there's something about these hormones that don't just allow sexual reproduction they don't just change the brain and bodily organs in the shape of of us they also bias us towards dispersal getting further and further away from primary caregivers in particular”