Physical development refers to the growth of the body structure including muscles, bones, and organs as well as comprising all motor and sensory development. Motor activity is dependent on muscle strength and coordination. Motor actions such as standing, sitting and running involve the large muscles whereas speech, vision and the use of hands and fingers engage the smaller muscles of the body. Sensory development includes the five senses, sight, taste, touch, smell, and hearing. The coordination and integration of perceptual input from these systems are controlled by the central nervous system.
Cognitive development describes activities such as thought, memory, reasoning, problem-solving and abstract thinking. The use of language necessitates symbolization and memory and is one of the most difficult of cognitive activities. The term language does not mean the spoken word, however. Speaking is a motor activity. Therefore, language and speech are operated by different areas of the brain. Comprehending and expressing language is a complex cognitive endeavor. Social development includes the child’s interactions with other people and involvement in social groups. The earliest social function is the attachment to mother leading to the development of relationships with adults and peers, assumption of social roles, adoption of group values and norms, adoption of a moral system, and eventually assuming a productive role in society are all social tasks. Emotional development refers to the maturing of personal behaviors and characteristics including developing a self-identity and esteem along with the ability to enter into mutual emotional relationships.
Sensory and motor domain development is most noticeable during the first year of life with physical growth beginning to slow at about one year of age. Parents may notice a decreased appetite at this time as they observe that their children seem to eat virtually nothing comparatively yet continue to grow and are healthy.