Here is your short paragraph on the development of Intelligent Behaviour !
Intelligence is an innate mental ability in an individual. This ability will grow with age and maturation.
The just born infant does not show any intelligent behaviour. Its behaviour is purely limited to the satisfaction of basic needs like hunger, thirst, elimination of wastes and sleep.
Gradually as the child comes in contact with the external world, it learns to understand different stimuli and to respond to them.
As the intelligence develops it can understand the emotions of parents and siblings and starts responding to them. Its behaviours become more selective and purposeful. It can understand the reactions of people and learns to discriminate them.
The development of intelligence makes the child to increase the curiosity to know the environment. Gradually the child learns to imitate the parents. By end of one year, it may start talking simple words like maa, paa, etc. By second year, the child learns to speak few simple words. By third year, it learns to differentiate self from others. It may get ready to read, learn, to discriminate right and wrong. By four years the child can learn to use language and speak in sentences.
Its perception becomes clearer. By sixth year thinking becomes better and can understand concrete objects. By eighth and ninth year, the child can understand people, their emotions and feelings. Gradually it learns to use complex sentences and also the fundamental skills in reading, writing and calculating. By twelfth year and onwards the child can think in abstract terms.
He can compare himself with others. He develops critical thinking, attitudes towards social groups. In this way, the intelligent behaviour is developed gradually in the child as the level of intelligence increase.