Subliminal: How Your Unconscious Mind Rules Your Behavior

Book review: It’s not reason that drives your decisions, it’s your quirky, unpredictable subconscious.


(Photo: Natalie Castellino)

Leonard Mlodinow knows we judge books by their covers. It’s just how our brains work. We slot complex ideas into simple categories, subliminally latch on to trivialities and convince ourselves we’re actually making a carefully reasoned decision about what we’d most like to read. It’s surprising, then, that at first glance the dust jacket of Mlodinow’s latest popular science book offers precious little flash to appeal to our fickle minds. All you see is dull black text reading Subliminal: How Your Unconscious Mind Rules Your Behavior. Tip the cover to the light, however, and translucent, barely decipherable words appear: “Pssst…Hey there. Yes: you, sexy. Buy this book now. You know you want it.”

Book buyers who succumb will find a somewhat disconcerting thesis: we have no idea why we do the things we do. Many decisions that we think of as conscious are, instead, the product of bizarre flights of our unconscious minds. Constituents may think they’re choosing a politician based on his persuasive platform and understanding of the issues, but in 72% of U.S. senate races, researchers found voters just picked the better-looking candidate. Worse, after making a decision, we immediately rationalize it and will swear up and down that it comes from an enlightened, logical place. “When it comes to understanding our feelings,” writes Mlodinow, “we humans have an odd mix of low ability and high confidence.”

Until recently, Mlodinow argues, the study of the unconscious was often dismissed as pop psychology. Though ­Sigmund Freud was ahead of his time in many ways, his conception of the unconscious—a teeming, sweaty place full of repressed memories and hidden desires to sleep with our parents—was well off the mark. Today, scientists are finally able to get a peak inside the black boxes of our minds. They’ve found a remarkably efficient, if somewhat quirky, mechanism. In one study, four French and four German wines were placed in an English supermarket while either French or ­German music was played from a tape deck on alternating days. Few of the wine buyers thought the music had anything to do with their decision, but on French music days 77% of the wine sold was French. When German music played, 73% of wine purchased was German.

Subliminal is of the Malcolm Gladwell/Jonah Lehrer school of pop science, and at times it can seem simplistic and a little scattershot. Luckily, Mlodinow is an entertaining, amiable guide. Besides being a theoretical physicist who wrote a number of popular science books and collaborated with Stephen Hawking on two bestsellers, Mlodinow also spent years as a Hollywood writer, working on episodes of Star Trek and coming up with the puzzles that stymied MacGyver (which may or may not increase your confidence in his scientific acumen). But by ­focusing on the science of the unconscious, Mlodinow makes us question some of our most basic assumptions.

In the world of business, for example, Mlodinow’s conclusions have big implications. Traditional economics is based on the fact that people make rational decisions based on their own self-interest. As more and more information about the unconscious is discovered, it turns out this may not be true. Take recent IPOs. It turns out that, rather than making a considered decision, cagey Wall Street traders are actually much more likely to invest in companies with an easily pronounceable ticker ­symbol than companies with a tongue twister of a name. Other studies have shown that stock prices can fluctuate depending on something as inconsequential as the weather in New York.

Perhaps the most jarring of Mlodinow’s conclusions, however, is about our self-conception. Most of us like to think we have a pretty fair image of ourselves. We assume that, like scientists, we look at the available data—our physical appearance, our interactions with others, the fact that we’re particularly good at remembering the lyrics to old-school hip hop songs—and then form a more-or-less objective opinion based on what we see. In fact, says Mlodinow, we’re more like attorneys. We start with a desired outcome (I am a smart, ­handsome man with an admirable knowledge of the Wu-Tang Clan back catalogue) and then cherry-pick the facts that bolster this premise.

This is why 94% of college professors say they’re above average and why a third of engineers are pretty sure they’re in the top 5% of their profession. It’s why CEOs of companies tend to be so overconfident when acquiring new assets, paying 40% more than a company’s current stock price because they’re convinced that under their leadership the firm can be run more profitably. We are, by design, hopelessly self-deluded.

Understanding this is humbling and a little depressing, but Mlodinow argues that these delusions of grandeur (or even ­adequacy) are absolutely vital. Without unreasonable optimism, why would anyone ever set out to become an NBA player or a great scientist or a famous actor? Why would any ice-age human, freezing in the fields of northern Europe, bother to go out hunting and gathering? Studies have shown that the people with the most accurate self-perceptions are actually often depressed. Having an inflated sense of self is a vital part of survival.

Far from a place of dank, Freudian repression, then, the new unconscious is “a gift of evolution that is crucial to our survival of a species.” Our unconscious lets us absent-mindedly walk down a crowded sidewalk without thinking about each sidestep and dodge. The same mechanism that causes us to lazily generalize, judging books by their covers and politicians by their bone structures, also allows us to see a knobby orange sphere, a specific object we’ve never encountered before, and instantly think “what a nice ripe orange.” Sure, we don’t often know why we make the decisions we do. Yes, we’re absurdly self-deluded. But that, it turns out, is probably for the best.