14 April 2023

Ricardo SANTIAGO ARAUJO – PhD defense

"Social learning and conformity in humans (Homo sapiens) and the fruit fly (Drosophila melanogaster)"

PhD defense in english


Team : PRADA (EDB)

Supervisors : Guillaume Isabel (CRCA-CBI) et Jean-Louis Hemptinne (EDB)

Committee members :

  • Examinateur: Director of Research Etienne Danchin, Université Toulouse III
  • Co-directeur: Prof. Guillaume Isabel, Université Toulouse III
  • Examinateur: Prof. Paul Seabright, Université Toulouse I
  • Examinateur: Dr. Sabine Noebel, Martin-Luther-University
  • Rapporteur: Prof. Andrew Whiten, University of Saint Andrews
  • Rapporteur:  Prof. Boris van Leeuwen, University of Tilburg
  • Rapporteur: Prof. Jean-Christophe Billeter, University of Groningen

Abstract :

Social learning encompasses all the distinct ways an individual learns from others and has already been identified in many non-human vertebrate and invertebrate species. Conformity, the disproportionate copying of the most common trait in a group, has come to the fore as a major driver in the emergence of culture.

In this interdisciplinary thesis, I study social learning, conformity and related processes in both humans (Homo sapiens, Chapter I) and the fruit fly (Drosophila melanogaster, Chapter II), to (1) build a better understanding of these phenomena across species; (2) find commonalities and differences between these two species; (3) help elucidate the nature of human conformity and (4) contribute to reconciling the distinct approaches from different disciplines.

In the first chapter, we used a novel experimental tool-set in two online experiments in humans to test the role of social information in people’s perception of their environment This provides evidence for conformity in two different contexts. Finally, we tested whether conformity is stronger in mate choice (as suggested by our colleagues in Toulouse), but find no evidence for it when compared to the alternative decision domain of ratio estimation.

In the second chapter, we focused on mate-copying in D. melanogaster to investigate how individuals adjust their behavior in response to social information that changes over time, specifically how they deal with sequentially presented items of conflicting social information. To tackle this question, we used a new video recording protocol in an experiment with two demonstrations one after the other, each consisting of an image of a model female copulating with a different male phenotype. Unexpectedly, in our experimental design, females tended to prefer the male phenotype of the first demonstration, which is suggestive of a primacy bias, defying the intuition that social learning would prioritize recent social information that should, in theory, reflect more accurately the current environment.


14 April 2023, 14h0017h00
CBI conference room - 4R4 building
University Paul Sabatier - Toulouse III

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