Do Chimpanzee Have an Economy?

Instructor Introduction

In Anthrbio 368, Introduction to Primate Behavior, students are asked to write a review paper on a topic of their choice—the only real restriction is that it needs to be about (or heavily incorporate) non-human primates. Most students elect to write about a topic from a long list of suggestions I provide, but some of the most interesting submissions come from students who strike out on their own to explore some new topic. Lin Yang’s essay on whether chimpanzees have an economy is a great encapsulation of the intellectual benefits of interdisciplinary thinking. “The economy” is something we specifically associate with humans, but Lin’s paper explores whether our closest living relatives have something resembling the key components of this centerpiece of human life. They make a convincing case that various building blocks necessary for an economy to emerge occur in chimps, including innovation, cooperation, hierarchy, and an understanding of the concept of ownership. I hope that others will enjoy reading it as much as I did.

— Stacy Rosenbaum

Do Chimpanzee Have an Economy?

Introduction

Humans have been trading goods for as long as 320,000 years, since the early Stone Age (Brooks et al., 2018). The flow of goods and, later, services was a powerful force of innovation through technology sharing, eventually paving the way for humankind to band into communities and a more formal economy in the Neolithic Era. There’s no agreement on how agriculture came to replace more transient lifestyles, but some argue that at the end of an ice age, human populations boomed due to newly abundant food and surpassed what the output of a hunter-gatherer system could produce (Porter-Szűcs, 2022). As production expanded, a social hierarchy emerged from who in a community had control over resources like food (Porter-Szűcs, 2022).

Nowadays, it’s evident that evolutionarily, this was the correct choice. That being said, do our relatives in the animal kingdom employ a similar survival method? The difference between the genome sequence of chimpanzees and humans is around 1.24% (Ebersberger et al., 2002). Studies on wild chimpanzees have demonstrated their social behavior starting from a young age (Moeller et al., 2016), and captive studies prove chimpanzees’ ability to make decisions within a social system (Call, 2001). Given the chimpanzees’ and humans’ shared preference for social behavior, it would not be out of the question for them to employ economy as a behavioral adaptation. Through reviewing various studies on chimpanzee behavior regarding resource production and distribution, I will investigate if chimpanzees have the concept of economy, and to what extent they exhibit behaviors that could be classified as an economy. To examine this, I will first define the parameters of an economy and then use existing studies in both wild and captive chimpanzees to make a judgement.

Hallmarks of Economy

To study an economy is to study the system’s production, distribution, and consumption (Krugman, 2009). Of course, there are many types of economies throughout history, and even more interpretations of what an economy has to include — in particular, modern economic study focuses on a market economy, which also includes specific principles such as supply and demand as an essential component (Polanyi, 1944). That being said, I am going to be defining “economy” in a very broad sense. In the following sections, I will be looking at production and innovation, division of labor, social hierarchy, token tasks and the basic principle of currency, and perception of “ownership” and the endowment effect in chimpanzees.

Production and Innovation

In order to have resources to trade or sell, one must first have a surplus of that resource for themselves. Humans, through the use of technology, have increased our ability to produce resources like food far past what we need for survival. Chimpanzees similarly use tools to access means for more food. In Boesch & Boesch (1983), researchers observed chimpanzees on the Ivory Coast using tools such as rocks to crack open nuts. Nuts are a high-calorie food, with the calories provided by the nuts commonly consumed in the study ranging from around 300 to above 500 calories per 100g. The study also reported chimpanzees bringing collected nuts to an “anvil” site to be cracked open. Different nuts were also cracked with different materials, based on the hardness of the nut shell. While this in itself does not denote economy, it does prove that chimpanzees can innovate resource production to increase output, an important part of a functional economic system. However, it should be noted that chimpanzees have yet to be found to store surplus resources, preferring to eat food quickly after finding it (McGrew & Feistner, 1992).

That being said, studies have repeatedly found that chimpanzees can delay gratification in captive studies. In Beran & Evans (2009), researchers found that chimpanzees were willing to do a computer task or even do nothing and wait for a larger food award to accumulate. Four chimpanzees were tested in three different trials; the first linked a computer task to a food reward, the second was an unlinked computer task, and the third was a waiting period for food with no distraction. The majority of the subjects had no significant change between trials. The ability to delay gratification demonstrated future planning, specifically the ability to plan to accumulate rewards for a later, better outcome. This is a basic skill that humans have honed that allows them to construct elaborate systems with delayed payouts (Cavanagh, 1982).

In a scenario where chimpanzees were provided with and taught to use cooking equipment, Warneken & Rosati (2015) discovered that chimpanzees were willing to invest time in “cooking” raw food and would delay eating raw food to accumulate it until they had the ability to cook it. It is possible that chimpanzees in the wild simply don't have the means to store supplies for a later date while transient — most of a chimpanzee’s diet is comprised of foods that go bad quickly, or that they don’t experience periods of food insecurity on a predictable enough basis for this level of planning ahead to be beneficial.

Division of Labor

Chimpanzees recognize the value of services such as grooming and are willing to trade food with others to receive the service. In a study of a captive colony of chimpanzees, food-sharing from chimp A to B increased grooming behavior from B to A, but not grooming behavior from A to B. This trend infers a more transactional relationship, rather than food-sharing and grooming as a result of a positive interpersonal relationship (de Waal, 1997). Based on external observation, the system seems to function more like reciprocity than a market economy since there wasn’t a 1-to-1 exchange established. Reciprocity is a more controversial outlook on the origins of the economy, arguing that the economy as a social system came out of a moral desire to “balance the scales” (Graber, 2011). Economists theorize that it was more present in smaller, early communities of humans and served to bond the community together, which would explain why chimpanzees have a similar system.

Chimpanzees don’t show a strict separation of labor based on sex; both males and females hunt, though females usually only hunt when no males are available. Females, based on observations of chimpanzees in Gombe National Park, are usually given meat in exchange for copulation by males, or they steal or beg for meat  (Teleki, 1973). Females also forage for food sources like insects (Pryor, 1981). The food-for-copulation exchange may indicate some basic system of “goods for services”, but the begging behavior may point to the exchange being more social or hierarchical rather than market exchange.

To an extent, chimpanzees do have assigned roles within a hunting party. “Impact hunters”, as named in Gilby et al. (2008), are male chimpanzees who usually initiate and lead group hunts. As a result, they often are the main target of attack by prey. The presence of them in a hunting party is shown to increase the rate of hunting of that party. However, since it’s unknown how formal these roles are, it’s difficult to compare this to the division of labor that occurs in an economy, especially since every chimpanzee in a hunting party consumes a similar amount of meat and they are not rewarded for their extra risk (Boesch, 1994).

Social Hierarchy

Social hierarchy is a major force in shaping an economy. Ultimately, economic exchange is the exchange of social power, and those with the most social power also have the most economic power (Porter-Szűcs, 2022).  This principle does apply to chimpanzee groups where social standing often determines access to food. Female chimpanzees in Taï National Park were found to have an internal social hierarchy, with a positive relationship between rank and winning competitions over food. Notably, rank and age did not correlate, meaning that rank was based on something more competitive than seniority (Wittig & Boesch, 2003). At least amongst the females in this group, social power in the form of being high-ranking meant more economic power in access to resources.

In another study of 4635 food-related interactions between nineteen chimpanzees, researchers observed that while high-ranked individuals did not have exclusive claims to resources, being a higher rank gave certain chimpanzees more control over the distribution of food amongst the group (de Waal, 1989). This shows that in chimpanzee groups, the flow of resources is greatly affected by an established social system, which is necessary for the existence of a proper economy (Rabie, 2016).

Endowment Effect and Ownership

The “endowment effect” is an economic phenomenon where an individual will assign more value to the property they perceive themselves to own (Reb & Connolly, 2007).  In economics, this causes people to make irrational decisions such as unwillingness to sell an object, even if they would make a profit. Interestingly, chimpanzees exhibit this behavior with both food and non-food objects. Chimpanzees were first tested on their preference between two foods and two toys and then given the less preferred food or toy. When offered the originally preferred food or toy for exchange, they showed unwillingness to trade (Brosnan et al., 2007). The only changed characteristic about the less preferred object is that it was now in the subject’s possession, so this study implied that chimpanzees perceive ownership over objects, and the concept of ownership is an important one when it comes to economic exchange.

Inarguable ownership is difficult to decipher in the wild due to the short-term nature of resources like food, but the begging and selective food-sharing covered earlier in this paper in Teleki (1973) would imply that chimpanzees recognize food to “belong” to another and that they have to perform certain behaviors to acquire it. However, there is also not a lot of research regarding this subject generally, so more wild and captive studies with ownership as the focus would be beneficial.

Token Tasks

Token tasks are a common experiment paradigm in primatology where researchers attempt to teach a primate to associate an object (the token) with a given value, represented by food or some other reward. The objective of these studies is to test the ability of an animal to practice symbolism by seeing the token as a symbol of another thing. This is the foundation of currency (Vasantkumar, 2019). Chimpanzees have repeatedly been shown to be very successful in this type of task. Captive chimpanzees in Beran et al. (2011) were able to successfully maximize the amount of food received when given a set of tokens that each corresponded to a food item. Generally, they quickly learned that the size of the individual tokens wasn’t representative of the size of the reward and started exclusively associating the number of tokens with the amount of food.

Chimpanzees have also shown the ability to exchange tokens in place of food with each other. In a captive study of mother-infant pairs, both mothers and their babies figured out that tokens represented food and started exchanging them with similar behavioral patterns as mother-infant pairs do with food (Tanaka & Yamamoto, 2009). Token tasks are exciting because they act in a similar way to currency —i.e. the tokens act as an emissary or middleman between trades. Chimpanzees being able to use tokens opens up the possibility of them being capable cognitively of going beyond directly trading goods. However, Beran & Parrish (2021) point out that there are a few shortcomings chimpanzees exhibit that prevent tokens from fully being a currency. For one, chimpanzees are limited to a single token type, making a currency system with two or more types of currencies impossible. Also, the value assigned to a token and its corresponding reward is not consistently equal. That being said, they also conclude that this may be a result of inadequate study circumstances, and further research should be conducted. In the wild, chimpanzees don’t exhibit token-trading behavior, but that may be due to having no drive to develop such behavior from a survival or social standpoint.

Discussion

One consistent theme I noticed within my review of studies was the need for further research. The majority of more complex or integrated studies are captive studies, and relatively little is known about the social dynamics and cognitive capacities of chimpanzees in the wild. Even within captive studies, more repetition would be extremely helpful. More generally, the field of bioeconomics is relatively new and thus a controversial way of approaching the study of economics, as it can call into question classical models based on pure rationality. As more work is done in this field, both with primates and other species of animals, researchers will be better able to tell the limitations of this framework in relation to both economics and the biology of decision-making. Additionally, humans are not chimpanzees, and explaining a human construct with purely evolutionary and biological reasoning would be disingenuous. At the very least, future research may be able to fill in a gap of knowledge on how early economies developed out of transient hunter-gatherer tribes, as there is much contention on this topic.

Finally, I’d like to acknowledge that while I chose chimpanzees as my subject of focus, similar behavior patterns have been observed in species such as macaques and capuchins ((Balasubramaniam & Berman, 2017; Brosnan & de Waal, 2003). In Balasubramaniam & Berman (2017), adult female rhesus macaques from Cayo Santiago were tracked on grooming behavior and tolerance for others using a given drinking source. Researchers found that there was a high correlation between grooming behavior and both increased tolerance for sharing a drinking source, and reciprocated grooming. Researchers also hypothesized some form of market exchange beyond simple reciprocity; lower-ranking macaques were more likely to perform grooming tasks to trade for drinking access, so it can be inferred that there is an expected exchange outside of rank. That being said, high-ranked macaques did not perform less grooming. Capuchins, like chimpanzees, show a remarkable understanding of tokens. In Brosnan & de Waal (2003), two capuchins were put in transparent cages next to each other. One was given a cucumber in exchange for a token, which it accepted. Then, the other was given a grape in exchange for a token. When the first capuchin was once again offered a cucumber in exchange for a token, it refused to accept the exchange after seeing what its neighbor was offered and was visibly annoyed (throwing the cucumber back at the researcher). Although chimpanzees are closer relatives of humans, other nonhuman primates also are capable of “proto-economy” behaviors. More research should be done into these and other species in this regard.

Conclusion

Based on the considerations made, chimps do not have a cohesive economy and have neither the cognitive ability nor the survival pressures to develop such a complex system in the wild. However, they do exhibit behaviors that align with early pre-economic behavior in humans. They can innovate, trade, work together, and even learn and use symbolism.

Innovation allows chimpanzees access to surplus resources through access to new food sources such as nuts or increasing efficiency of hunting tasks through the use of spears (Pruetz & Bertolani, 2007).  Production is also assisted by the ability to accumulate food and delay gratification. Even wild chimpanzees, who primarily eat foods that aren’t storable for a long time such as fruit or meat, show the ability to do such by bringing nuts to crack open to a sedentary tool site. Chimpanzees also recognize hierarchy and status affect resource distribution, one of the most prominent features of the economy. They also understand both ownership and the transfer of ownership via trade. They can understand and use symbolism at a basic rudimentary level as proven by token tasks, although it should be recognized that it is nowhere near the level of human ability.

Even though chimpanzees have very little structure and organization in their resource gathering and exchange compared to anything that we would describe as an economy, it’s easy to recognize similarities in those behaviors and how early humans may have transferred from hunting and gathering groups to sedentary groups with more complex social systems. Based on the studies presented, I would also conclude that although there are many separate behaviors they exhibit that are shared with human economic behavior, chimpanzees don’t have economies because these behaviors are not organized together, and they have not shown the capacity to elevate behaviors in tandem to such a degree, as shown in Beran & Parrish (2021).

Works Cited

1. Brooks, A. S., Yellen, J. E., Potts, R., Behrensmeyer, A. K., Deino, A. L., Leslie, D. E., Ambrose, S. H., Ferguson, J. R., d’Errico, F., Zipkin, A. M., Whittaker, S., Post, J., Veatch, E. G., Foecke, K., & Clark, J. B. (2018). Long-distance stone transport and pigment use in the earliest Middle Stone Age. Science, 360(6384), 90–94. https://doi.org/10.1126/science.aao2646
2. Porter-Szűcs, B. (2022, August). A World without an Economy. History 282: History and the Economy. Ann Arbor.
3. Ebersberger, I., Metzler, D., Schwarz, C., & Pääbo, S. (2002). Genomewide comparison of DNA sequences between humans and chimpanzees. The American Journal of Human Genetics, 70(6), 1490-1497.
4. Moeller, A. H., Foerster, S., Wilson, M. L., Pusey, A. E., Hahn, B. H., & Ochman, H. (2016). Social behavior shapes the chimpanzee pan-microbiome. Science Advances, 2(1). https://doi.org/10.1126/sciadv.1500997
5. Call, J. (2001). Chimpanzee social cognition. Trends in Cognitive Sciences, 5(9), 388–393. https://doi.org/10.1016/s1364-6613(00)01728-9
6. Krugman, P. (2009). What is Economics? In Economics (pp. 2–2). essay, Wroth Publishers.
7. Polanyi, K. (1944). Chapter Four: Societies and Economic Systems. In The Great Transformation. essay, Farrar & Rinehart.
8. Boesch, C., & Boesch, H. (1983). Optimisation of nut-cracking with natural hammers by wild chimpanzees. Behaviour, 83(3–4), 265–286. https://doi.org/10.1163/156853983x00192
9. McGrew, W. C., & Feistner, A. T. (1992). Two Nonhuman Primate Models for the Evolution of Human Food Sharing: Chimpanzees and Callitrichids. In The Adapted Mind : Evolutionary Psychology and the Generation of Culture (pp. 236–237). essay, Oxford University Press.
10. Beran, M. J., & Evans, T. A. (2009). Delay of gratification by chimpanzees (Pan troglodytes) in working and waiting situations. Behavioural Processes, 80(2), 177–181. https://doi.org/10.1016/j.beproc.2008.11.008
11. Cavanagh, G. F. (1982). Free Enterprise Values: Delayed Gratification or Immediate Fulfillment. Review of Social Economy, 40(3), 330–339. http://www.jstor.org/stable/29769128
12. Warneken, F., & Rosati, A. G. (2015). Cognitive capacities for cooking in chimpanzees. Proceedings of the Royal Society B: Biological Sciences, 282(1809), 20150229. https://doi.org/10.1098/rspb.2015.0229
13. de Waal, F. B. M. (1997). The chimpanzee’s service economy: Food for grooming. Evolution and Human Behavior, 18(6), 375–386. https://doi.org/10.1016/s1090-5138(97)00085-8
14. Graber, D. (2011). Chapter Five: A Brief Treatise on the Moral Grounds of Economic Relations. In Debt: The First 5,000 Years. essay, Melville House.
15. Teleki, G. (1973). The Omnivorous Chimpanzee. Scientific American, 228(1), 32–42. doi:10.1038/scientificamerican0173-32
16. Pryor, F. L. (1981). A Survey of the Economic Systems of Wild Chimpanzees and Baboons. Journal of Economic Issues, 15(1), 33–59. http://www.jstor.org/stable/4224995
17. Gilby, I. C., Eberly, L. E., & Wrangham, R. W. (2008). Economic profitability of social predation among wild chimpanzees: Individual variation promotes cooperation. Animal Behaviour, 75(2), 351–360. https://doi.org/10.1016/j.anbehav.2007.06.008
18. Boesch, C. (1994). Cooperative hunting in wild chimpanzees. Animal Behaviour, 48(3), 653–667. https://doi.org/10.1006/anbe.1994.1285
19. Rabie, M. (2016). Economy and Society. In: A Theory of Sustainable Sociocultural and Economic Development. Palgrave Macmillan, New York. https://doi.org/10.1007/978-1-137-57952-2_6
20. Wittig, R. M., & Boesch, C. (2003). Food Competition and Linear Dominance Hierarchy Among Female Chimpanzees of the Taï National Park. International Journal of Primatology, 24(4), 847–867. https://doi.org/10.1023/a:1024632923180
21. de Waal, F. B. M. (1989). Food sharing and reciprocal obligations among chimpanzees. Journal of Human Evolution, 18(5), 433–459. https://doi.org/10.1016/0047-2484(89)90074-2
22. Vasantkumar, C. (2019). Towards a commodity theory of token money: on ‘Gold standard thinking in a fiat currency world.’ Journal of Cultural Economy, 12(4), 317–335. https://doi.org/10.1080/17530350.2019.1614086
23. Beran, M. J., Evans, T. A., & Hoyle, D. (2011). Numerical judgments by chimpanzees (Pan troglodytes) in a token economy. Journal of Experimental Psychology: Animal Behavior Processes, 37(2), 165–174. https://doi.org/10.1037/a0021472
24. Tanaka, M., & Yamamoto, S. (2009). Token transfer between mother and offspring chimpanzees (Pan troglodytes): Mother–offspring interaction in a competitive situation. Animal Cognition, 12(S1), 19–26. https://doi.org/10.1007/s10071-009-0270-8
25. Beran, M. J., & Parrish, A. E. (2021). Non-human primate token use shows possibilities but also limitations for establishing a form of currency. Philosophical Transactions of the Royal Society B: Biological Sciences, 376(1819), 20190675. https://doi.org/10.1098/rstb.2019.0675
26. Reb, J., & Connolly, T. (2007). Possession, feelings of ownership and the endowment effect. Judgment and Decision Making, 2(2), 107–114. doi:10.1017/S1930297500000085
27. Brosnan, S. F., Jones, O. D., Lambeth, S. P., Mareno, M. C., Richardson, A. S., & Schapiro, S. J. (2007). Endowment effects in chimpanzees. Current Biology, 17(19), 1704–1707. https://doi.org/10.1016/j.cub.2007.08.059
28. Pruetz, J. D., & Bertolani, P. (2007). Savanna chimpanzees, Pan troglodytes verus, Hunt with tools. Current Biology, 17(5), 412–417. https://doi.org/10.1016/j.cub.2006.12.042
29. Balasubramaniam, K.N., & Berman, C.M. (2017). Grooming interchange for resource tolerance: biological markets principles within a group of free-ranging rhesus macaques. Behaviour, 154(11), 1145-1176. https://doi.org/10.1163/1568539X-00003462
30. Brosnan, S. F., & de Waal, F. B. (2003). Monkeys reject unequal pay. Nature, 425(6955), 297–299. https://doi.org/10.1038/nature01963