I don't know anything about this particular one, but just because it's a case study in a textbook doesn't mean it's true. There are lots of untruths that get propagated long after they've been debunked.
But they’re citing a survey where people literally didn’t get it. That, if not made up, factually supports the claim that some people really do think 1/3 is less than 1/4.
I really liked the 1/3 pound “thickburgers”. I don’t think it was just some dying chain trying to spread rumors about how stupid people didn't understand their marketing and that’s why they “died” (they’re still very much alive last I checked).
