Sonya’s parents have been encouraging her to walk for several months by standing her up and holding her hands. paul’s parents have let him achieve motor milestones on his own, without encouraging or him. the fact that sonya and paul both started walking independently at about the same age can be best explained by

Maturation

Explanation:

In psychology maturation is the process of learning to cope and react in an emotionally appropriate way. It does not necessarily happen along with aging or physical growth, but is a part of growth and development. Both Sonya and Paul both started walking independently at about the same age because they were reacting in an appropriate manner.