Student or Learner
Back in 1985, Geoffrey Raisman, now at University College London, discovered a unique trait of the olfactory system (sense of smell).
(Scientific American Mind; Volume 16, Number 3; Mending the Spinal Cord)
Is this a word that a native English speaker would not normally know, as it were, and would need an explanation, which the author so farsightedly provided?
I'd say about half the populace would know what olfactory means.
The author of the quote was being helpful, I would say, rather than patronising*.
*'Patronising' means condescendingly explaining something you already understand**.
**I was being patronising when I wrote that***.
***I expect you knew that.
I'll get my coat and hat.