This act takes place in the laboratories of major research universities. It’s main character being a cognitive scientist investigating numerosity in animals and humans. Enter our monkeys (still yelling that they are not CHIMPS!). Some of them learn quantity pictures of 4 numbers in the order 1->2->3->4, others learns 4->3->2->1. But when they are presented with the 5, 6, and 7 quantities something odd happens. The 1->2->3->4 monkeys can place the new quantities in order, but the 4->3->2->1 monkeys can not. How strange.
Perhaps if they learn 4->5->6 and 6->5->4, they will do better? Or perhaps the monkey Peano has been to see them? Alas, it appears that monkey Peano snuck into the lab late one night and explained the principle of a first number and its successors. His 4->5->6 children know what to do with 7, 8, and 9 but not 1, 2, and 3. But while the 6->5->4 progeny are stumped by 7, 8, and 9, they can order 1, 2, and 3.
What is going on here? Do Peano’s Axioms actually explain the cognitive process of counting? Will the answer appear in Act III? Or will we be left with questions?
Note: The relevant journal articles on the studies with the rhesus macaques are available here along with a number of other interesting papers on numbers in animals and humans.
The monkeys (we are not CHIMPS!) have their stories told in:
Brannon, E. M., & Terrace , H. S. (1998). Order of the Numerosities 1 to 9 by
Monkeys. Science, 282, 746-749
Brannon, E. M., & Terrace , H. S. (2000). Representation of the Numerosities 1-9 by
Rhesus Macaques (Macaca mulatta). Journal of Experimental Psychology, 26(1),
Brannon, E. M., & Terrace , H. S. (2002). The Evolution and Ontogeny of Ordinal
Numerical Ability In M. Bekoff, C. Allen, & G. M. Burghardt (Eds.). The
Cognitive Animal (pp. 197-204). Cambridge, MA: The MIT Press
Terrace, H. S., Son, L. K., & Brannon , E. M. (2003). Serial Expertise of Rhesus
Macaques. Psychological Science, 14(1), 66-73