Just accept the quest Ignar's Snack that he will give you and make a lump of raw sugar to get the knowledge

Amity game is ridiculous. Just wave.

sometimes it works "fine"

Ignar NPC
Ignar Knowledge
Ignar's Snack Quest

Reroll until low interest (35ish) then

Narava
Belon
Hayaa
Wapra
Baan

Lots of rng tho, most entries have 18 interest so multiple tries required. Finish him with your hand

Ignar's snack is part of Sophistication III, doesn't seem to require energy to learn