What makes you say that so definitely?
Funny enough I have the opposite opinion, human brains are the type of thinking we have most experience with - so we've devised our input methods around what we notice most, and so will be able to most easily train the AI.
I also believe that we'll be abke to reduce the noise to a level lower than actual person variation fairly easily, cause an AI has the benefit of being able to scale to a populous size - no human even has that much experience with humans