This is an interesting experiment that throws new, and disturbing, light on the workings of the human mind:
Open the .gif and watch it, then scroll down.
Did you guess carrot too?
Experiments carried out by university lecturers on students, psychologists on colleagues, and teachers on pupils have shown that between 66% and 90% come up with the answer Carrot. Why this is so, is somewhat puzzling. Tests simply asking participants to name a vegetable came up with random answers. Bizarrely, another common response was "something orange." I thought most people knew the difference between "Choose a vegetable" and "Choose a colour."
Unfortunately, this is as far as scientists have managed to advance the issue. There are several hypotheses floating round, but none of them have been validated. We know that people associate arithmetics with carrots apparently. But we don't know why. Expect an international inquiry into this most urgent matter.