The early development of numerical reasoning.

Children of age 1-4 years were found capable of engaging in numerical reasoning. Children were presented with a task in which they placed a set of objects one by one into an opaque container. An experimenter then visibly performed either an addition, a subtraction, or no transformation on the screened set. Children were then instructed to remove all objects from the container. Across two experiments, children searched for and removed the correct number of objects when set numerosity was small. Knowledge of numerical identity and knowledge of the effects of addition and subtraction transformations on numerosity were present even in children who had not yet begun to count verbally. These findings provide evidence that the emergence of numerical reasoning does not depend upon the prior development of a verbal counting ability or upon cultural experience with numbers.