They are extremely intelligent for a mollusk(like, these folks are family with slugs and clamshells), but they are not that intelligent if you compare them to a pig or a dog.
Their main brain is after all very small(although huuuge for a mollusk), most of it is dedicated to the processing of vision, with two big lumps next to the eyes, and there's a small lump in between these two for the brain proper.
oh wow, I'd never heard of this. Reading https://en.wikipedia.org/wiki/Flicker_fusion_threshold - now I think I understand why I can always tell GM vehicles with LED taillights at night. I can spot them a mile away, literally, because their taillights blink slower than others and I can see it, and it drives me crazy.
