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