Are there relationships between types of human taste thresholds? This study looked at previously recorded impulses on isolated taste fibers during tongue stimulation of primates to see if there was a correlation between electrophysiology in primates and humans. The highest correlations between tastes were for the sugars and quinine hydrochloride/tannins. These two taste classes, which were grouped into “pleasant” and “unpleasant” clusters, are common to humans, chimpanzees, macaques, and marmosets. The various salts and acids cluster found in this study was not found to be shared by previously recorded primate species.
These two broad clusters of pleasant and unpleasant tastes are thought to represent major selective pressure on the primate gustatory system. The low thresholds for sugars and high thresholds for quinine and tannin could indicate the evolution of optimal feeding strategies to maximize nutritional intake and avoid toxic substances.