After birth, as observed, the newborn reclines in an uncontrolled manner and has disorganized activity.Then as the age advances, the child acquires better co-ordination of motor activity. The child reacts to his/her environment in a willful manner, until he/she blends into a fully integrated and autonomous individual.
Behavior development is the series of changes happening over time in child’s perception, learning, thinking, language and personality.
Piaget's theory of cognitive development suggests that children typically move through four different stages of mental development. His theory focuses not only on understanding how children acquire knowledge, but also on understanding the nature of intelligence. In other words, how a child constructs mental model of the world is properly explained by Piaget.
These 4 stages are:
Personal Social development relates to child’s interpersonal and social skills. A summary of personal social and emotional milestones is as follows:
Key Developmental Milestones: Personal Social and Emotional Age
| Age | Milestones |
| 2 months | Social smile |
| 3 months | Recognizing the mother |
| 6 months | Smiles at mirror image |
| 9 months | Waves the hand ‘bye-bye’ |
| 12 months | Plays a simple ball game | 36 months | Knows gender |
Social smile and recognition of mother: The infant with intention regards the face of the mother or the examiner by the age of 1 month.He smiles back in return (known as Social Smile) when the examiner tries to speak to him or smiles to him at 2 months. The child recognizes the mother by the age of 3 months. At 6 months, the infant enjoys watching his own image in the mirror. Children show anxiety on meeting strangers on reaching age of 7 -8 months.
Toys: The child resists if a toy is pulled from his hand by the age of 7 months. He makes a determined effort to get a toy kept a little out of his reach by the age of 9 months.
Mimicry: At 1 year of age, the child repeats any performance that evokes appreciative response from parents and later mimics the action carried out by mother at home.
The child waves hand, bye-bye at 9 months and plays a simple ball game at 1 year and knows gender at 3 years.
The infant’s Social smile should not be delayed beyond 3 months. The child should laugh in play situation before 6-8 months. A child should be easy to console and should not stiffen while crying by the age of 1 year.
A 2 year old child should not kick, bite and scream easily without definite provocation. By 2 years, the child should make positive eye contact with other children and elders.
A child in constant motion who does not play with other children at between 3 to 5 years requires detailed medical assessment and is a cause of concern for parents.
Likewise (i) if the baby does not become alert when the mother is around by 2-3 months, (ii) the infant does not reach for dropped objects by 6-7 months, (iii) Is not interested in peek-a-boo game by 8-9 months, (iv) shows no interest in searching hidden objects by 12 months. (v) Is not able to categorize similar objects such as animal versus vehicles. (vi) does not know his/her full name by 3 years. (vii) By 4 years, he should be able to distinguish a short line from a long line (viii) the child should be able to count sequentially by 4 ½ years of age. (ix) Should distinguish between color’s by 5 years of age. (x) if a 5 year old child does not remember his/ her own address or birthday should raise a concern for parents.
The child should be screened for behavioral development using simple, rapid and accurate techniques by the doctor or attendant. If this indicates delayed development, then the child should be medically examined to find the exact cause for this delay.