As grim as it is, and depending on your degree of skepticism: craniotomy, psychoactive drugs, concussions, etc.. Reminds me of the scene in Ex Machina where he

As grim as it is, and depending on your degree of skepticism: craniotomy, psychoactive drugs, concussions, etc.. Reminds me of the scene in Ex Machina where he cuts himself to make sure he still bleeds - a physical realization of a turing test.