I'm reading Kahneman's Thinking, Fast and Slow and I've stopped on this:

90% of the students who saw the CRT in normal font made at least one mistake in the test, but the proportion dropped to 35% when the font was barely legible. You read this correctly: performance was better with the bad font.

This seems like an important finding, but I can't find references in the book (Kindle) or on the Web. Does anybody know any real evidence for this claim? EDIT: I found the original paper

Do you think that people could behave rationally with such a simple intervention?

simple intro to CRT

EDIT: fixed spelling in title