Seminar

Decisive but Rigid: How Tsimane Children Build Consensus in Networks

Isabelle Brocas (University of Southern California)

June 30, 2026, 11:30–12:30

Toulouse

Room Auditorium 4 (First floor- TSE Building)

IAST General Seminar

Abstract

We compare how 126 Tsimane children (ages 6–13) from the Bolivian Amazon and 150 children from a Los Angeles school (LILA, ages 5–8) solve a networked consensus task, in which six players with only local information must agree on one color within 30 seconds. Despite being several years older, the Tsimane converge at the level of LILA kindergarteners rather than their LILA age-peers — a developmental displacement that age alone cannot explain. The two populations are alike in unexpected ways: the same speed of first choice, the same endogenous self-sorting into leader, debater, and closer roles, and the same average rate of majority-following. Where they part is flexibility. Tsimane children tend to choose once and commit, locking onto the first mover's color far more often and revising far less. This decisiveness — not confusion — appears to be what limits their convergence, placing them on the rigid side of the flexibility trade-off that lets older LILA children excel. Within the Tsimane, age and household market involvement predict coordination success, while formal schooling does not.