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Causal understanding is not necessary for the improvement of culturally evolving technology

Nature Human Behaviour (2019) | Download Citation

Abstract

Bows and arrows, houses and kayaks are just a few examples of the highly optimized tools that humans have produced and used to colonize new environments1,2. Because there is much evidence that humans’ cognitive abilities are unparalleled3,4, many believe that such technologies resulted from our superior causal reasoning abilities5,6,7. However, others have stressed that the high dimensionality of human technologies makes them very difficult to understand causally8. Instead, they argue that optimized technologies emerge through the retention of small improvements across generations without requiring understanding of how these technologies work1,9. Here we show that a physical artefact becomes progressively optimized across generations of social learners in the absence of explicit causal understanding. Moreover, we find that the transmission of causal models across generations has no noticeable effect on the pace of cultural evolution. The reason is that participants do not spontaneously create multidimensional causal theories but, instead, mainly produce simplistic models related to a salient dimension. Finally, we show that the transmission of these inaccurate theories constrains learners’ exploration and has downstream effects on their understanding. These results indicate that complex technologies need not result from enhanced causal reasoning but, instead, can emerge from the accumulation of improvements made across generations.

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Data availability

The data that support the findings of this study are available at https://osf.io/afwmr/.

Code availability

Codes used in this paper are available at https://osf.io/afwmr/.

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Acknowledgements

We thank J. Clewett for valuable advice about the building of the wheel, F. Gosselin and A. Deymier for organizing the experimental sessions, and members of the Laboratory for Experimental Anthropology for helpful discussions during the development of the experimental protocol. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement number 748310. Support from the ANR-Labex Institute for Advanced Study in Toulouse is acknowledged. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

Author information

Affiliations

  1. Human Behaviour and Cultural Evolution Group, Department of Biosciences, University of Exeter, Penryn, UK

    • Maxime Derex
    •  & Alex Mesoudi
  2. Laboratory for Experimental Anthropology, ETHICS (EA 7446), Catholic University of Lille, Lille, France

    • Maxime Derex
  3. Toulouse School of Economics (TSM Research), Centre National de la Recherche Scientifique, University of Toulouse Capitole, Toulouse, France

    • Jean-François Bonnefon
  4. Institute of Human Origins, Arizona State University, Tempe, AZ, USA

    • Robert Boyd
  5. School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA

    • Robert Boyd

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Contributions

R.B. and M.D. developed the research question. M.D. conceived the experimental task and protocol with input from A.M. and J.-F.B. M.D. performed the experiment, analysed the data and wrote the manuscript with input from all authors.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Maxime Derex.

Supplementary information

  1. Supplementary Information

    Supplementary Results, Supplementary Figures 1–9, Supplementary Tables 1–7, and Supplementary Methods.

  2. Reporting Summary

  3. SI Guide

    Description and links to Supplementary Videos 1–4, Supplementary Data, and Supplementary Software.

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DOI

https://doi.org/10.1038/s41562-019-0567-9

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