Press release

Lessons of economics from non-human primates


Gal token exchange. Credit Elisabetta Visalberghi
Gal token exchange. Credit Elisabetta Visalberghi

Capuchin monkeys, a South-American primate species whose lineage split from ours more than 35 million years ago, recognizes which objects are most valuable to be used as tokens to obtain food. These findings emerge from a new series of studies carried out by Cnr-Istc, published online in the journal Animal Cognition

In humans, money replaced barter about 6 centuries before Christ and quickly became the most efficient means of obtaining goods and services, affecting all aspects of our life. To understand what factors allowed the transition from barter to our current economic system, it is important to investigate the evolutionary origins of the use of money in non-human primates, our closest relatives.

In a study published in the journal Animal Cognition, researchers from the Unit of Cognitive Primatology of the Institute of Cognitive Sciences and Technologies of the National Research Council (Cnr-Istc) in Rome and of the Institute for Advanced Study (IAST) in Toulouse, in collaboration with the Institute Jean Nicod, Ecole Normale Superieure in Paris, have examined the bartering behavior of capuchin monkeys, small South American monkeys whose lineage split from ours about 35 million years ago. "Six capuchin monkeys were involved in two experiments in which they were required to exchange tokens, including colored poker chips, bolts and other hardware items", explains Elsa Addessi, research scientist at Cnr-Istc.  "Each monkey was provided with a set of four different items: familiar tokens (known to the monkeys from previous studies) and non-familiar tokens (introduced in the present study) that, when exchanged with the experimenter, led to a food reward; invalid tokens, used in previous experiments, but which now lost their exchange value, and unknown objects, without any exchange value". 

Researchers found that monkeys readily recognized the validity of tokens as a medium of exchange regardless of their familiarity. "We have shown that capuchins are able to categorize tokens on the basis of their validity," continues Francesca De Petrillo, research scientist at Iast in Toulouse. "Similarly to what happens in human beings, that recognize more rapidly Euro coins than the old Lira, capuchins exchanged first valid tokens than invalid tokens and valueless objects, regardless of their familiarity". "Capuchins are also capable of performing multiple exchanges," Addessi adds. "When in a second experiment we gave them a piece of low-preferred food that could be traded with a token, which in turn could be exchanged for a high-quality food, capuchins performed this series of advantageous exchanges. Not eating a food immediately and exchanging it for a token requires a high level of self-control and it is worthy only when it is advantageous". 
"Our studies prove that the precursors of a proto-monetary economy can be identified also in monkeys that are evolutionarily distant from us," concludes Sacha Bourgeois-Gironde, an economist at the Institute Jean Nicod in Paris. "Capuchin monkeys easily learned how to use food as a token, a process that in humans led to the emergence of money."

In brief

Who: Institute of cognitive sciences and technologies (Cnr-Istc) in Rome; Institute for Advanced Study (Iast) in Toulouse; Institute Jean Nicod, Ecole Normale Superieure in Paris 

What: A study published in the journal Animal Cognition examined the bartering behavior of capuchin monkeys:
De Petrillo, F., Caroli, M., Gori, E., Micucci, A., Gastaldi, S., Bourgeois-Gironde, S., & Addessi, E. (2019). Evolutionary origins of money categorization and exchange: an experimental investigation in tufted capuchin monkeys (Sapajus spp.). Animal Cognition, 1-18.
Link to the full article:

For further information: Elsa Addessi, Institute of cognitive sciences and technologies (Cnr-Istc) in Rome,

Capo ufficio stampa:
Marco Ferrazzoli
06 4993 3383

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