NUMERICAL REPRESENTATIONS IN PRIMATES

Research has demonstrated that human infants and nonhuman primates hav e a rudimentary numerical system that enables them to count objects or events, More recently, however, studies using a preferential looking paradigm have suggested that preverbal human infants are capable of si mple arithmetical operations, such as adding and subtracting a small n umber of visually presented objects, These findings implicate a relati vely sophisticated representational system in the absence of language. To explore the evolutionary origins of this capacity, we present data from an experiment with wild rhesus monkeys (Macaca mulatta) that met hodologically mirrors those conducted on human infants, Results sugges t that rhesus monkeys detect additive and subtractive changes in the n umber of objects present in their visual field, Given the methodologic al and empirical similarities, it ap pears that nonhuman primates such as rhesus monkeys may also have access to arithmetical representation s, although alternative explanations must be considered for both prima te species.