A cloud of chemicals. One researcher detects a smell. The other does not. What happens next? Science.

A food laboratory from 1935, though sadly not the one in the story (flickr/University of Washington).
Like I always say, there are two kinds of people in this world: normal tasters and supertasters. But no really, there really are two distinct populations within humanity, when it comes to taste-sensitivity.
Supertasters, taste scientists have shown, possess certain gene variants. Supertasters have more of those bumps on their tongues, which are technically called fungiform papillae and contain the taste buds. Not only can supertasters taste some bitter substances that normal (or non-taster, as per the scientific literature) people can't, but many tastes are more intense for them.
This week, Andrew Han took up the question of how scientists discovered this subgroup of superhumans cleverly disguised as people just like the rest of us.
Turns out, it all began with an accident at a DuPont chemical lab: A cloud of chemicals goes up. One scientist detects a smell. The other does not.
Alas, the scene did not portend the beginning of a new comic book series, but it did lead to a paper that was published in the Proceedings of the National Academy of Sciences. In the paper, the scientists themselves describe the episode:
Some time ago the author had occasion to prepare a quantity of phenyl thio carbamide, and while placing it in a bottle the dust flew around in the air. Another occupant of the laboratory, Dr. C. R. Noller, complained of the bitter taste of the dust, but the author, who was much closer, observed no taste and so stated. He even tasted some of the crystals and assured Dr. Noller they were tasteless but Dr. Noller was equally certain it was the dust he tasted. He tried some of the crystals and found them extremely bitter. With these two diverse observations as a starting point, a large number of people were investigated and it was established that this peculiarity was not connected with age, race or sex. Men, women, elderly persons, children, negroes, Chinese, Germans and Italians were all shown to have in their ranks both tasters and non-tasters.
As Han notes, the last couple decades have seen tons of work on supertasters as new genetic tools have begun to unlock the mechanics of their blessing/curse. There's even a plausible evolutionary narrative for why such a trait might have developed and propagated. " Chemicals like PROP [or phenyl thio carbamide] can cause thyroid problems and toxic alkaloids found in poisonous plants often taste bitter," Han writes, "so the sense to avoid ingesting plants that produce these toxins might confer an evolutionary advantage."
