TeachingBase

Worksheets: Cooperation experiments with chimps and bonobos

In a series of experiments, anthropologists wanted to find out whether chimpanzees and bonobos work together and share a common source of food. Results tell us something about the role of social tolerance in cooperative foraging.

Teaching material type Experiment, Video, Worksheet

Subject Areas Biology, Human Evolution

Suitable Grade Levels 3-5, 6-8, 9-12

Concepts Cooperation, Social temperament

Content Anchors Cross-species, Games

Author: Susan Hanisch

Related Lesson Materials

Human Evolution Resources

Our collection of resources for learning about human origins and evolution

Reading text: Cooperative foraging

A reading text about cooperative foraging in the animal kingdom and in our early ancestors

Worksheet: Natural selection of traits for cooperative foraging

A worksheet in which students calculate and graph the changes in the frequencies of traits related to cooperative foraging in a population over several generations, exploring the role of variation, fitness consequences and trait inheritance in evolutionary change.

Related Literature

Tolerance Allows Bonobos to Outperform Chimpanzees on a Cooperative Task

Hare, B., Melis, A. P., Woods, V., Hastings, S., & Wrangham, R. (2007). Tolerance Allows Bonobos to Outperform Chimpanzees on a Cooperative Task. Current Biology, 17(7), 619–623. https://doi.org/10.1016/j.cub.2007.02.040

To understand constraints on the evolution of cooperation, we compared the ability of bonobos and chimpanzees to cooperatively solve a food-retrieval problem. We addressed two hypotheses. The “emotional-reactivity hypothesis” predicts that bonobos will cooperate more successfully because tolerance levels are higher in bonobos. This prediction is inspired by studies of domesticated animals; such studies suggest that selection on emotional reactivity can influence the ability to solve social problems [1, 2]. In contrast, the “hunting hypothesis” predicts that chimpanzees will cooperate more successfully because only chimpanzees have been reported to cooperatively hunt in the wild [3-5]. We indexed emotional reactivity by measuring social tolerance while the animals were cofeeding and found that bonobos were more tolerant of cofeeding than chimpanzees. In addition, during cofeeding tests only bonobos exhibited socio-sexual behavior, and they played more. When presented with a task of retrieving food that was difficult to monopolize, bonobos and chimpanzees were equally cooperative. However, when the food reward was highly monopolizable, bonobos were more successful than chimpanzees at cooperating to retrieve it. These results support the emotional-reactivity hypothesis. Selection on temperament may in part explain the variance in cooperative ability across species, including hominoids. © 2007 Elsevier Ltd. All rights reserved.

Engineering cooperation in chimpanzees: tolerance constraints on cooperation

Melis, A. P., Hare, B., & Tomasello, M. (2006). Engineering cooperation in chimpanzees: tolerance constraints on cooperation. Animal Behaviour, 72(2), 275–286.

The cooperative abilities of captive chimpanzees, Pan troglodytes, in experiments do not match the sophistication that might be predicted based on their naturally occurring cooperative behaviours. This discrepancy might partly be because in previous experiments potential chimpanzee cooperators were partnered without regard to their social relationship. We investigated the ability of chimpanzee dyads to solve a physical task cooperatively in relation to their interindividual tolerance levels. Pairs that were most capable of sharing food outside the test were also able to cooperate spontaneously (by simultaneously pulling two ropes) to obtain food. In contrast, pairs that were less inclined to share food outside of the test were unlikely to cooperate. Furthermore, previously successful subjects stopped cooperating when paired with a less tolerant partner, even when the food rewards were presented in a dispersed and divisible form to reduce competition between subjects. These results show that although chimpanzees are capable of spontaneous cooperation in a novel instrumental task, tolerance acts as a constraint on their ability to solve such cooperative problems. This finding highlights the importance of controlling such social constraints in future experiments on chimpanzee cooperation, and suggests that the evolution of human-like cooperative skills might have been preceded by the evolution of a more egalitarian social system and a more human-like temperament. © 2006 The Association for the Study of Animal Behaviour.