Honestly this makes the most sense to me. I guessed first before thinking it through and if I were doing the test and it were timed I might've just guessed.

> I would bet that quite a few people just guess when they find this type of question too difficult.

Psych research is such garbage. Of course people are going to start guessing if the problems are boring and they can't solve them. They tried to account for this by comparing timings of only correct answers. But on a multiple choice test, even random guessing will be correct (and fast!) sometimes.