As researchers have studied the growth and the anatomy of the human body, scientists are continuing to learn more and more about our learning abilities and capacities. We now know that our brains are not fully developed at birth. In fact, a baby's brain weighs about one quarter of what an adult's brain weighs. The brain grows very rapidly during the first several years of life. Furthermore, cognitive development is a child's ability to learn and solve problems. For instance, this includes a two-month-old baby learning to explore the environment with hands or eyes. This is also exhibited when a four-year-old child is learning arithmetic. There are many ways in which cognitive development is exemplified during growth and youth. Social and emotional development is a child's ability to interact with others, including helping themselves and exercising self-control. Examples of such would include a six-week-old baby smiling or a ten-month-old baby waving bye-bye. Another example may be a four-year-old child knowing how to take-turns during group games and activities. As young children are not only growing physically during early childhood development, they are also growing mentally. Though the physical growth is easily detected and visible to one’s naked eye, the psychological development is best evaluated during direct observation of social interactions. Children of this age range continue to advance their skills in observing and interacting with the world around them. They also make tremendous leaps in how they process, store, and use information. Loving relationships give young children a sense of comfort, safety, confidence and encouragement. Nurturing connections teach toddlers how to form friendships, how to communicate emotions and how to deal with challenges. Supportive relationships with parents, adults, and friends also help children develop trust, empathy, compassion, and a sense of right and wrong. Cognitive and social development of children ages two-four are remarkable stages of growth and learning. Cognitive Development of Children Ages Two to Four At the age of two, a toddler is starting to understand the relationship between objects. For example, a child will be able to match similar shapes when handling shape sorting toys and simple jigsaw puzzles. Children will also begin to recognize the purpose of numbers in counting objects. These activities are generally a fun and enjoyable experience at this age group as their understanding of cause and effect develops. Children tend to become even further interested in winding up toys and turning lights and appliances on and off. Two, three and even early aged four-year-olds are considered pre-operational thinkers, whereas they rely solely on the physical appearance of objects as opposed to ideas. They focus on only one relationship at a time and often see things fr