This document discusses human life span development. It covers four main stages of development: physical, intellectual, emotional, and social. During infancy, which is defined as age 0-2, infants experience rapid physical, intellectual, emotional, and social development. They develop fine and gross motor skills, bond with caregivers, and begin to form relationships with others. Groups researched and created posters on the major skills infants typically master by age two in these areas of development.