Technical intelligence and culture: Nut cracking in humans and chimpanzees.
According to the technical intelligence hypothesis, humans are superior to all other animal species in understanding and using tools. However, the vast majority of comparative studies between humans and chimpanzees, both proficient tool users, have not controlled for the effects of age, prior knowledge, past experience, rearing conditions, or differences in experimental procedures. We tested whether humans are superior to chimpanzees in selecting better tools, using them more dexteriously, achieving higher performance and gaining access to more resource as predicted under the technical intelligence hypothesis.



Aka and Mbendjele hunter-gatherers in the rainforest of Central African Republic and the Republic of Congo, respectively, and Taï chimpanzees in the rainforest of Côte d'Ivoire were observed cracking hard Panda oleosa nuts with different tools, as well as the soft Coula edulis and Elaeis guinensis nuts. The nut-cracking techniques, hammer material selection and two efficiency measures were compared.



As predicted, the Aka and the Mbendjele were able to exploit more species of hard nuts in the forest than chimpanzees. However, the chimpanzees were sometimes more efficient than the humans. Social roles differed between the two species, with the Aka and especially the Mbendjele exhibiting cooperation between nut-crackers whereas the chimpanzees were mainly individualistic.



Observations of nut-cracking by humans and chimpanzees only partially supported the technical intelligence hypothesis as higher degrees of flexibility in tool selection seen in chimpanzees compensated for use of less efficient tool material than in humans. Nut cracking was a stronger social undertaking in humans than in chimpanzees.
Department of Primatology, Max Planck Institute of Evolutionary Anthropology, Leipzig, Germany.
Christophe
0000-0001-9538-7858
C
Boesch
Department of Social Anthropology, University College London, London, United Kingdom.
Daša
D
Bombjaková
Thompson writing program, University of Duke, Durham.
Adam
A
Boyette
Department of Primatology, Max Planck Institute of Evolutionary Anthropology, Leipzig, Germany.
Amelia
A
Meier
D000818:Animals; D000885:Anthropology, Physical; D002488:Central African Republic; D003223:Congo; D007560:Cote d'Ivoire; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology; D009754:Nuts; D002679:Pan troglodytes / Q000502:physiology*; D053001:Tool Use Behavior / Q000502:physiology*
chimpanzees; efficiency; humans; nut cracking; technical intelligence; tool use