The dramatic differences found by Piaget in the development of preschoolers and elementary-age children

A child undergoes rapid physiological and cognitive developments in the first few years.  Preschoolers or toddlers slowly shed their ‘ego-centric’ view.  This means that a newborn baby does not have the capacity to think of and for others.  This ability to understand that there are others in the world is slowly gained during the years 0-3.  After a year and half the toddler begins to verbally express its likes and dislikes.  This is an important cognitive milestone, for the language ability has significant ramifications for psychosocial and later academic performance.  The preschool stage is when most of the gross and fine motor ability is acquired and exercised.  So the graduation from moving limbs to crawling to walking signify the baby’s growing capacity for self-expression in physical space.  During the elementary school age, the child understands that the world is comprised of people like itself with similar motivations and needs.  During this stage crucial psychosocial skills are acquired, as the child learns to negotiate its own needs with that of others.

References:

Herbert Ginsburg and Sylvia Opper (1979), Piaget’s Theory of Intellectual Development, Prentice Hall, ISBN 0-13-675140-7, p. 152

Santrock, J.W. (2008). A Topical Approach To Life-Span Development (pp.211-216). New York, NY: McGraw-Hill