Auditory thresholds compatible with optimal speech reception likely evolved before the human-chimpanzee split

Research output: Contribution to journalResearch articleContributedpeer-review



The anatomy of the auditory region of fossil hominins may shed light on the emergence of human spoken language. Humans differ from other great apes in several features of the external, middle and inner ear (e.g., short external ear canal, small tympanic membrane, large oval window). However, the functional implications of these differences remain poorly understood as comparative audiometric data from great apes are scarce and conflicting. Here, we measure the sound transfer function of the external and middle ears of humans, chimpanzees and bonobos, using laser-Doppler vibrometry and finite element analysis. This sound transfer function affects auditory thresholds, which relate to speech reception thresholds in humans. Unexpectedly we find that external and middle ears of chimpanzees and bonobos transfer sound better than human ones in the frequency range of spoken language. Our results suggest that auditory thresholds of the last common ancestor of Homo and Pan were already compatible with speech reception as observed in humans. Therefore, it seems unlikely that the morphological evolution observed in the bony auditory region of fossil hominins was driven by the emergence of spoken language. Instead, the peculiar human configuration may be a by-product of morpho-functional constraints linked to brain expansion.


Original languageEnglish
Article number20732
Number of pages12
JournalScientific reports
Issue number1
Publication statusPublished - 25 Nov 2023

External IDs

PubMedCentral PMC10676368
ORCID /0000-0002-3061-0171/work/148145065
Scopus 85177806130



  • Animals, Humans, Pan troglodytes/anatomy & histology, Auditory Threshold, Pan paniscus, Speech, Hominidae/anatomy & histology