The term "cognitive development" refers to the growth and maturation of cognitive processes such as thinking, perception, memory, and problem-solving. It involves the development of intellectual abilities and skills, as well as the acquisition of knowledge and understanding.

Cognitive development begins in infancy and continues throughout childhood and adolescence. It is influenced by a variety of factors including genetics, environment, social interactions, and experiences.

The stages of cognitive development were proposed by the Swiss psychologist Jean Piaget. According to Piaget, children progress through four main stages of cognitive development:

1. Sensorimotor stage (birth to around 2 years old): Infants explore and learn about the world through their senses and motor actions. They develop object permanence and begin to understand cause and effect.

2. Preoperational stage (2 to 7 years old): Children develop symbolic thinking and language skills. They can engage in pretend play and understand the perspective of others, but their thinking is still largely egocentric and they struggle with logical reasoning.

3. Concrete operational stage (7 to 11 years old): Children become capable of more logical and concrete thinking. They can solve problems through trial and error, understand conservation, and classify objects based on multiple criteria.

4. Formal operational stage (11 years old and beyond): Adolescents and adults develop the ability to think abstractly and hypothetically. They can engage in more complex reasoning, consider multiple perspectives, and think about future possibilities.

Cognitive development is an essential aspect of overall human development. It plays a crucial role in academic achievement, problem-solving abilities, decision-making skills, and social interactions. Understanding cognitive development can help parents, educators, and caregivers provide appropriate support and stimulation to promote optimal cognitive growth in children.