Jean Piaget made a systematic study of cognitive development among children of different age groups and he categorized it into different developmental stages. These stages are-Sensory-motor stage (0 to 2 years)pre-operational stage (2 to 6 years)Concrete operational stage (6 to 11 years)Formal Operational stage (11+ years to adolescence).Cognitive development is much more than the addition of new facts and ideas to an existing store of information. According to Piaget, our thinking processes change radically, though slowly, from birth to maturity because we constantly strive to make sense of the world.?Piaget identified four factors that influence the development of a child-Maturation,Activity,Social experiences,Equilibration.So option (1) is the correct answer.?Important PointsMaturation: One of the most important influences on the way we make sense of the world is maturation, the unfolding of the biological changes that are genetically programmed. Parents and teachers have little impact on this aspect of cognitive development, except to be sure that children get the nourishment and care they need to be healthy.Activity: It is accepted that there can be no knowledge development without relating objects. within the environment, an individual acquires knowledge not by passively copying objects in the environment but by acting upon them.Example, when the child learns from the perceptual properties of objects, by noting their weight, and the color of the harness, it is physical experience or first-hand information.Social Experience: Social experiences plays an important role in the development of the child. The child learns about its environment, and people through social interaction.Equilibration: Equilibration involves the assimilation of information to fit with an individual's own existing mental schemas and the accommodation of information by adapting it their way of thinking.Additional InformationStagesChan?gesSensory-motor stage Senses are teachersReflex actionsIntimate Behaviorpre-operational stageLanguage developmentIrreversibilityEgocentrismAnimismConcrete operational stageLogic beginsReversibilityClassificationConservationFormal Operational stageHypothetical-deductive thinkingDivergent/Convergent thinking.Creative Thinking.