God Soul Mind Brain by Michael S. A. Graziano Read Free Book Online Page A

the blue sky, the texture of that bare tree; am I aware of myself; am I aware of being aware?” I suggest that you are querying the machinery whose specialty is to decide, “Is brain X aware of thing Y?” In this view, the same circuitry, the same type of computations, come into play whether you are perceiving someone else’s awareness of Y or perceiving your own awareness of Y. The primary difference is that in one perceptual model, the property of awareness has been assigned to a location in someone else’s head, bound to a model of someone else’s mind, whereas in the other perceptual model the property of awareness has been assigned to a location inside your own head, bound to a model of your own mind.

The perceived location of the mind

    In the mid 1900s, Critchley surveyed people’s notions of the location of the self. He asked people where their souls or minds were located. Some pointed to their chests, some to their stomachs, most to their heads. The most common perceived location was right between the eyes. As in all perception, when we perceive our minds, we don’t merely perceive a set of free-floating properties—thoughts and emotions and awareness. We also perceive those properties to be attached to a physical location. When you look at a tree and ask yourself, “Am I aware of it?” the answer, according to the circuitry in your brain that computes such things, is not merely “yes” but “yes and the awareness is located inside me.”

    To be clear, I don’t mean simply that people think it reasonable, or deduce, or intellectually conclude that the mind must be inside the body. Where it reasonably ought to be, and where it feels like it is, are two different propositions. What I mean here is that regardless of reason, most people feel consciousness to be inside their heads.

    The question of where the soul is located, however, becomes complicated in the case of out-of-body experiences. Under some conditions, especially near sleep, close to death, or in light anesthesia, the brain’s model of the self becomes unhinged a little and begins to assign non-standard locations. A patient may report the sensation of standing beside the bed, or floating near the ceiling looking down on his own body.

    This out-of-body illusion can be reliably induced. In one recent experiment by a group of scientists in Geneva, Blanke and colleagues electrically stimulated the surface of people’s brains. The reasons were medical—to map out the brain prior to surgery. In some cases, when electrical stimulation was applied to a region of the cerebral cortex called the temporal-parietal junction (TPJ), an out-of-body experience was induced. People felt that their minds were floating outside their bodies. The stimulation was interfering with the machinery that normally assigns a location to the self. It was inducing a mismatch between the actual location of the body and the perceived location of the self. Even if the brain is intact and not being artificially electrically stimulated, it is possible to produce an out-of-body experience by tricking the perceptual system with an ingenious set of video cameras and display screens, as shown by the scientist Ehrsson.

    How can we make sense of the out-of-body experience? How can your brain be in one location, cranking data, actively processing information, while at the same time you experience that processing as if it were located somewhere else entirely? The answer to the riddle is that we don’t directly experience our own minds. We experience them by proxy, through a perceptual model—and the model, computed and constructed by the brain, can sometimes be wrong. The key realization here is that the process of perception applies not only to the outside world, but also to the inner world. We perceive our own thoughts, our own cognition, our own emotions, with all the gnarly implications of the term “perception.” We construct a perceptual model of our own minds, the model