Intellectual development refers to the changes that occur in a persons capacities for thinking, reasoning, relating, judging, conceptualizing, and other aspects of cognitive development as a result of growth and experience. It is how a person perceives, thinks, and gains understanding of their world through the relations of genetic and learning factors. Intellectual development is all about learning, and it is how individuals organize their minds, ideas, and thoughts to make sense of the world they live in.

The main areas of intellectual development include reasoning, intelligence, language, and memory. Intellectual development milestones vary by age, and some examples include:

• Vocabulary increasing to 2,000 words, sentences of five or more words in five and six-year-olds.
• Understanding fractions, money, and the concept of space in seven to 11-year-olds.
• Adolescents aged 12 to 18 are capable of complex thinking, including the ability to think abstractly about possibilities, reason from known principles, consider many points of view, and think about the process of thinking.

Parents and schools play an important role in a childs intellectual development. Parents can help children learn and develop through exposure to new things and by making different materials available at home, including household objects, toys, and books. Schools provide formal instruction and the acquisition of reading and writing skills, which stimulate the growth of intellectual capacities.