The 35,000 Decisions: Why Choice Is the Brain's Greatest Magic Trick

The 35,000 Decisions: Why Choice Is the Brain's Greatest Magic Trick

The fluorescent lights of the supermarket hummed with the kind of institutional indifference that erases time. Sarah had been standing in aisle seven for what felt like a geological epoch, though her watch said ninety-three seconds. Her cart held onions, garlic, a can of San Marzano tomatoes, a wedge of Parmigiano-Reggiano that had cost more than she wanted to admit, and a baguette that was almost certainly still soft enough to be worth buying. The dinner she was planning was decided. The wine was decided. The question, ostensibly, was simple: which pasta?

There were two boxes in her hands. One was Barilla, the other was De Cecco. The packaging was nearly identical. The price was nearly identical. The ingredient lists were nearly identical. The shapes were nearly identical. She had eaten both a thousand times, in sauces she would not be able to tell apart if presented blindfolded, in meals she would remember neither in a week nor regret in a year.

And yet she could not decide.

If you had watched Sarah in that moment, you would not have seen a woman engaged in any noticeable cognitive activity. Her face was calm. Her eyes were not darting. Her breathing was normal. Her posture suggested someone resting, not someone calculating. From the outside, the moment looked empty, a paused frame in a life otherwise too busy to pause. Inside, however, her brain was performing one of the most complicated computations in the known universe. It was weighing two options, retrieving memories of past meals, predicting future satisfaction, integrating budget constraints, registering social signals from a friend who had once mentioned a preference, reading brand cues that had been engineered by industrial designers to nudge her in one direction or another, comparing prices down to fractions of a cent per gram, simulating regret, calculating anticipated pleasure, and producing, at the end of it all, a single motor command that would allow her hand to deposit one box in her cart and return the other to the shelf.

That command arrived. She chose the De Cecco. She moved on.

She will never think about this choice again.

This book is about that choice, and the trillions like it. In the chapters ahead, we are going to do something that is at once simple and strange. We are going to take the most ordinary feature of human life, the act of choosing, and we are going to lift it up to the light. We are going to ask how a three-pound organ locked inside a dark skull, with no direct access to the outside world, with only electrochemical pulses traveling along axons at speeds that an old laptop would find embarrassing, manages to produce what looks for all the world like magic: the smooth, reliable, almost always correct experience of knowing what to do next.

The answers we find will not be mystical. They will be biological. They will be chemical. They will involve specific neurons, in specific places, firing in specific patterns, releasing specific molecules onto specific receptors. The "magic" of choice, we will discover, has a signature. It can be measured, predicted, perturbed, and in many cases, reverse-engineered. By the time you finish this book, the feeling that there is something ineffably mysterious about your own decisions will not have disappeared — but it will have a shape.

We begin, in this opening chapter, by setting the stage. We will look at the sheer scale of the problem. We will trace, briefly, how human beings have tried to understand choice for two and a half millennia, and where those attempts got stuck. We will see why neuroscience was the missing piece that finally allowed the puzzle to come together. And we will preview the single most important molecule in this story — a neurotransmitter called dopamine — whose discovery will consume us in Chapter 2.

But first, the pasta aisle. Because before we can understand the brain, we have to feel the problem.

The Astonishing Math of Everyday Choice

The number you have probably heard is thirty-five thousand. It circulates through productivity blogs and TED talks and airport-distributed self-help books, often attributed to a researcher at Cornell named Brian Wansink. The figure is, by Wansink's own later admission, a back-of-the-envelope estimate rather than a measured count. He did not literally watch 200,000 people make 35,000 decisions each. What he did, in a 2006 paper in the *Journal of Decision Making*, was take a more modest tally of college students who recorded their food-related choices, scale it up, and round generously. Subsequent reanalyses and replication efforts have suggested the actual count may be closer to a few hundred to a few thousand conscious decisions per day, depending on the definition.

So the precise number is contested. What is not contested, however, is the qualitative claim it gestures at: human beings make an extraordinary number of choices every day, and the vast majority of them happen without anything we would recognize as deliberation.

To see why the number matters, even approximately, it helps to itemize what is actually being counted. There are the obvious decisions: what to wear, what to eat, whether to take the call, whether to send the email, whether to accept the meeting, whether to take the job. These are the choices we narrate to ourselves when we talk about our "decision-making life." They are real, and they can be consequential, and we will spend time on them in later chapters.

But there is a deeper stratum of choice that is invisible by design. As you read this sentence, your eyes are making roughly three to four saccades per second, each one a decision about where to land next. Your pupils are dilating and constricting dozens of times per minute, deciding how much light to admit. Your posture is being continuously re-negotiated by hundreds of small muscular adjustments, each one a choice between micro-alternatives. Your auditory system is making constant decisions about which sounds to amplify and which to suppress — a phenomenon called auditory streaming — so that you can hear your name in a noisy room without being driven mad by the air conditioner. Your heart is being sped up and slowed down, your breath is being modulated, your stomach is being told how much acid to secrete. At the level of single neurons, the firing patterns along your spinal cord represent thousands of decisions per second about how much force to apply to which muscle fibers. None of this rises to the level of what we call "choosing." All of it is choice in the broader biological sense.

Wansink's estimate, even if overstated, is pointing at something important. The modern human brain is doing more *type-1*, fast, automatic, unconscious processing than even the most generous interpretation of his number suggests. Behavioral scientists sometimes call these System 1 processes, a term popularized by Daniel Kahneman in his 2011 book *Thinking, Fast and Slow*. System 1 is what handles the pasta choice, the route to work, the recognition of a familiar face in a crowd. System 2 is what handles the tax return, the philosophical argument, the chess problem. Both are choices in the relevant sense. Both consume neural resources. Both can be done well or poorly. But they are not equally visible to the chooser.

This invisibility is itself a major puzzle. If the brain is making thirty-five thousand decisions a day, why are you aware of perhaps a hundred? Why does consciousness pick out so few of them? We will return to this question in Chapter 6, when we discuss the global workspace theory of consciousness and Bernard Baars's proposal that only those neural computations that win a kind of internal competition for broadcast get to enter the theater of awareness. For now, the relevant point is simpler: the act of choosing is far more pervasive, far more continuous, and far more biologically expensive than introspection suggest