To me it is clear why. Imagine someone told you "answer immediately, top of your head: what's the best seasoning?". You'd just blurt out whatever specific you associated with pleasing seasoning (and that would be a good answer). Now imagine someone said "answer immediately, off the top of your head, but without offending any culture, gender, without a cultural bias, and without being presumptuous of the listener's socio-economic status (and if you fail one of these, someone dies) what's the best seasoning?" Even without the way that is going to lead to all sorts of compromising and second guessing in the answer space, simply only a fraction now of your brain is left to associate about the question due to just holding all that other stuff in there.