ON THE DEVELOPMENT OF MORE AND LESS1

More and less were analyzed into two meaning dimensions, “existence” (derived from children's early language) and “quantity,” which were hypothesized to be developmentally related to acts of addition and subtraction. Two experiments tested two- and three-year-olds' comprehension of these concepts when initially equal or unequal rows were added to, subtracted from or left static. Addition and subtraction had little effect on Ss' comprehension of either term. Ss understood more first when number characteristics of the array were relatively large, suggesting ‘many’ as an intermediate stage of meaning for more. No evidence was found for less meaning more as others have claimed. Ss understood less later than more, a difference attributed to the restricted use of less as ‘smaller in amount.’