The Believing Brain - Michael Shermer [58]
We often learn how the brain works from when it doesn’t work right. Gazzaniga notes, for example, that patients with “reduplicative paramnesia” believe that there are copies of people or places. They mix these copies up into one experience or story that makes perfect sense to them even if it sounds ridiculous to everyone around them. “One such patient believed the New York hospital where she was being treated was actually her home in Maine,” Gazzaniga recalled. “When her doctor asked how this could be her home if there were elevators in the hallway, she said, ‘Doctor, do you know how much it cost me to have those put in?’ The interpreter will go to great lengths to make sure the inputs it receives are woven together to make sense—even when it must make great leaps to do so. Of course, these do not appear as ‘great leaps’ to the patient, but rather as clear evidence from the world around him or her.”34 This is, in part, what I mean by patternicity and agenticity, although these are just descriptive terms for a cognitive process. What we really want to know is what the neural correlates are for this process, and for the generation of sensed presences and other forms of ephemeral agenticities. This left-hemisphere interpreter is a good candidate for where it happens.
My brother-in-law Fred Ziel, who has climbed many of the highest and most dangerous peaks of the Himalayas, tells me that he has twice experienced a sensed presence. The first time was when he was frostbitten and without oxygen at the limit of physical effort above the Hillary Step, the last hurdle on Mount Everest’s southeast ridge. The second time was on Everest’s north ridge after he collapsed from dehydration and hypoxia (oxygen deprivation) at twenty-six thousand feet. Both times he was alone and wishing he had a companion, which his brain obligingly provided. Tellingly, when I asked his opinion as a medical doctor on possible hemispheric differences to account for such phenomena, Fred noted, “Both times the sense was on my right side, perhaps related to being left-handed.” Neuroscientists believe that our “sense of self” is located primarily in the temporal lobe of the left hemisphere, and that our divided brain means that left- and right-brain circuits are crisscrossed so that, for example, the right visual field is registered in the left hemisphere’s visual cortex. Perhaps the oxygen deprivation at twenty-six thousand feet, or the bitter cold, or the pain of frostbite, or the feeling of being abandoned and alone—or some combination thereof—triggered the left temporal lobe in Fred’s brain to generate “another self.” Since the brain has only one body and one mind schema—one self—a second self can be perceived only as another being outside the body, a sensed presence nearby.
The sensed presence may be the left-hemisphere interpreter’s explanation for right-hemisphere anomalies. Or there may be neural network conflicts in body or mind schemas. Or it may be loneliness and fear extending our normal sensed presence of real others into imagining ephemeral companions. Whatever its cause, the fact that it happens under so many different conditions tells us that the presence is inside the head and not outside the body.
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These examples of and explanations for superstition and magical thinking, rooted in association learning, theory of mind, sensed presences, the supersense, and the like—under the rubric of patternicity and agenticity—are not causal explanations per se. Labeling a cognitive process is a heuristic to help us get our minds around a problem to be solved or a mystery to be explained, but they are only labels, in the same way that calling a set of hallucinatory symptoms schizophrenia explains the cause of those symptoms. We need to bore deeper into the brain itself to understand the ultimate nature of belief and the true cause of our tendency to find meaningful patterns in meaningful