ABSTRACT
This chapter considers the development of logical reasoning, beginning with Piaget’s conception of logic as intrinsic to biological self-regulation. Psychological research reveals a sensorimotor logic of action already developing in infancy and shows that even preschool children routinely make logically correct inferences. The development of logic is in large part the development of (metalogical) understanding about the nature of logic and associated regulation of one’s inferences. Research shows systematic and universal progress in logical reasoning over the first 12 years of life, leading to the ability (beginning about age 11 or 12 years) to determine the logical implications of ideas one deems hypothetical or even false. Development beyond that is much less universal and related more to experience and education than to age. There is extensive evidence that even adults fall far short of logical perfection, with substantial individual differences. Mathematical reasoning, which also involves matters of logical necessity, shows a similar developmental pattern of universal childhood progress over the first 12 years, with substantial individual differences in further development and systematic errors at all ages.
