Rhesus Macaque

Earlier this week I wrote about the developmental and evolutionary origins of large number representation. A series of studies in human infants, monkeys, rats, and fish demonstrated that animals and humans spontaneously represent large (>4), abstract, approximate numerosities. Animals, human infants, and human adults, show the same ratio signatures (based on Weber's Law). Adult tamarins are on par with 9-month-old human infants. With age or training, discriminability becomes more precise, and the the critical ratio is reduced a bit. There is good evidence that the large number…