Gray Matters

Although The Wandering Mind is a conversational essay, it doesn’t wander. Corballis, like Jarrett, distills to essentials. Memory, thinking about the future, reading other people, storytelling, dreams, hallucinations, and creativity each get a chapter. Each is a function of our “default-mode network,” a large swath of brain not dedicated to perception or responses to the immediate environment. “The brain is a bit like a small town,” he explains, “with people milling around, going about their business. When some big event occurs, such as a football game, the people then flock to the football ground, while the rest of the town grows quiet.” Then we mill around again. 

We are programmed to alternate between mind-wandering and paying attention. .  .  . [W]e need to escape the here and now, and consider possible futures, mull over past mistakes, understand how other people’s minds work. 

You can get your best ideas washing dishes. There are studies.  

Corballis is polite, and it may be his comforting bent that led him to avoid the most troublesome question about wandering minds. Noting that “the Freudian idea that dreams are symbolic disguises of shameful or forbidden thoughts has largely lost favor,” he writes that dreams “may serve .  .  . to activate the unconscious, to create the internal terrains for later mental meanderings.” I wish he had addressed whether (or how) the unconscious may take the controls, still the core claim of much psychotherapy and a major theme in behavioral finance—which has convinced me that even people who consider themselves financially sophisticated have no idea what they’re doing with their money. In Corballis’s most revelatory chapter, on hallucinations, he suggests that “perception is fundamentally driven from within, with information from the world serving merely to guide what we see, hear and smell.” He adds, characteristically, “Perhaps that’s an exaggeration, but hallucination tells us that there’s more to perception than meets the eye.”

Jarrett addresses aspects of this huge thought as well. Under “Myth #33: The Brain Perceives the World As It Is,” he breaks the news that we’re actually living a self-created “virtual reality experience. .  .  . The truth is that we catch mere glimpses of physical reality.” Three or four times every second, for example, you close your eyes and see nothing—a mechanism to prevent blurring when you shift your gaze. To compensate, your brain seems to backdate your sense of how long objects have been in their current locations. It takes about a tenth of a second for information to come in, but your brain hides the lag, “constantly predicting how the world probably is now based on how it was a moment ago.”

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