As a human, you can mentally rotate an object, recognize a face and do all these extremely expensive computations effortlessly. For doing that, you need to have a model of the local universe loaded up to your brain, which in addition is constantly filtering out hypothetical scenes and movements which do not satisfy the principle of least action (e.g., you don't think Steve Jobs is under your desk right now). Many of such computations, however, are of the kind that could easily be carried out by quantum computers, provided you would load them up with the correct model of their neighborhood. Now imagine that the many worlds interpretation of QM holds: All the things in the cosmos "span" multiple universes. There are an infinite number of replicas of yourself in ever so slightly different universes. If your brain is indeed a quantum computer, your brain is cross-linked to all your other brains. There is no need to load up any model anymore. All that you needed is to perceive the reality as it comes!
Of course this "argument" (I would call it a theory) is full of holes, but the topic makes for some interesting talks with philosophers.