Md. Hauser et al., NUMERICAL REPRESENTATIONS IN PRIMATES, Proceedings of the National Academy of Sciences of the United Statesof America, 93(4), 1996, pp. 1514-1517
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.