noriviola

The study directly investigate this, you will find it in Fig. 8: Dyadic preferences for (mis)tunings of the major 3rd. What you see is that (modern) people preferences are NEITHER to just intonation (integer ratios) OR equal temperament (which they were presumably exposed to). What happens that depends on timbre (and this is new too) participant prefer tuning that slightly deviates from just intonation but NOT exactly equal temperament!!

Full study: https://www.nature.com/articles/s41467-024-45812-z

The first paper you mention is this one: Universal and Non-universal Features of Musical Pitch Perception Revealed by Singing https://www.sciencedirect.com/science/article/pii/S096098221...

The hypothesis that Tsimane people "are not able to hear them" is refuted in this paper: Perceptual fusion of musical notes by native Amazonians suggests universal representations of musical intervals https://www.nature.com/articles/s41467-020-16448-6