All children are unique and a lot of their developmental milestones happen naturally as they get older, however some can be affected by different life factors, such as health, environment and background and more specific skills can be learnt and encouraged. There is an expected pattern of development but all children are individual and therefore the rate will vary.
There are four categories of development:
(Birth - 1 year) - The development of control over one's own body in both gross and fine motor skills is the infant's primary physical task, culminating toward the end of the first year in walking. (1-2 years) - The infant perfects the gross and fine motor skills that emerged during the first year by developing balance, coordination, stability, and an improved ability to manipulate objects. (2-3 years) - The child develops increased strength and uses motor skills to master challenges in the environment, such as stairs, balls, playground equipment, cutlery, crayons, and other objects. (3-6 years) - Most basic gross motor abilities have emerged. Existing skills are practiced and perfected, and the child develops mastery in applying motor skills to increasingly challenging and complex situations. (6-11 years) - The child practices, refines, and masters complex gross and fine motor and perceptual-motor skills. (12-19 years) - Physiological changes at puberty promote rapid growth, the maturity of sexual organs, and development of secondary sex characteristics.
(Birth - 1 year) - Cognition begins with alertness, awareness, recognition, and interest in visual, auditory, and tactile (touch) stimuli. As motor development improves, the infant begins to explore and manipulate objects and develops some understanding of their properties. (1-2 years) - The emergence of symbolic thought is central to cognitive development. This results in the ability to understand and produce language. (2-3 years) - Perfection of language skills and the use of language to communicate with others is the principle cognitive task. (3-5 years) - Language develops rapidly. The child uses language as a communication tool. Thinking is concrete and egocentric in nature. Problem solving is illogical and magical thinking and fantasies are prevalent. (6-11 years) - Concrete operational thinking replaces egocentric cognition. The child's thinking becomes more logical and rational. The child develops the ability to understand others' perspectives. (12-19 years) - During early adolescence, precursors to formal operational thinking appear, including a limited ability to think hypothetically and to take multiple perspectives. During middle and late adolescence formal operational thinking becomes well developed and integrated in a significant percentage of adolescents.
(Birth - 1 year) - The most important social task is the development of attachment to the primary carer, most often the child's mother. (Age 1-2 years) - The child develops affectionate and trusting relationships with other family members and with adults outside the family. The child can also be engaged in simple games and play. (Age 2-3 years) - The child develops relationships with other children; they will play in the presence of, rather than in interaction with, other children. Children also begin to imitate social roles at this time. (3-6 years) - The child expands social relationships outside the family and develops interactive and cooperative play skills with peers. The child begins to understand, explore, imitate, and practice social roles. The child learns concepts of "right" and "wrong" and begins to understand the nature of rules. He experiences guilt when he has done something wrong. (6-11 years) - Relationships outside the family increase in importance, including the development of friendships and participation in a peer group. The...