Running Head : Quantity discrimination for substances Infants make quantity discriminations for substances

Previous studies suggest that infants can track small groups of solid objects, and infants can respond when these quantities change. But, surprisingly, earlier work is equivocal about whether infants can track continuous substances, such as piles of sand. Experiment 1 used a habituation paradigm to show that 3-, 7and 10-month-old infants, can register changes in the size of piles of sand that they see poured from a container when there is a 1 to 4 ratio. In Experiment 2 we tested whether 7-, 10-, and 13-month-old infants could discriminate a 1 to 2 ratio. We found that females could discriminate the difference but males could not. These findings constitute the youngest evidence of successful quantity discriminations for a noncohesive substance and begin to characterize the nature of the representation for non-cohesive entities.