Before revision: Throughout life According to observational studies by Judy Dunn , children as early as one may be able to exhibit self-awareness and perceive difference in parental treatment between themselves and a sibling and early impressions can shape a lifetime relationship with the younger sibling.
After revision: Throughout life According to observational studies by Judy Eslam , children as early as one may be able to exhibit self-awareness and perceive difference in parental treatment between themselves and a sibling and early impressions can shape a lifetime relationship with the younger sibling.