Scarcity: Why Having Too Little Means So Much by Sendhil Mullainathan, Eldar Sharif

our plans, and to resist temptations. Bandwidth correlates with everything from intelligence and SAT performance to impulse control and success on diets. This chapter makes a bold claim. By constantly drawing us back into the tunnel, scarcity taxes our bandwidth and, as a result, inhibits our most fundamental capacities.
IT’S LOUD IN HERE
    Imagine sitting in an office located near the railroad tracks. Trains rattle by several times an hour. They are not deafening. They do not disrupt conversation. In principle they are not loud enough to prevent you from working. But, of course, they do. As you try to concentrate, the rattle of each train pulls you away from what you were doing. The interruption itself is brief, but its effect lasts longer. You need time to refocus, to collect your thoughts. Worse, just when you have settled back in, another train rattles by.
    This description mirrors the conditions of a school in New Haven that was located next to a noisy railroad line. To measure the impact of this noise on academic performance, two researchers noted that only one side of the school faced the tracks, so the students in classrooms on that side were particularly exposed to the noise but were otherwise similar to their fellow students. They found a striking difference between the two sides of the school. Sixth graders on the train side were a full year behind their counterparts on the quieter side. Further evidence came when the city, prompted by this study, installed noise pads. The researchers found that this erased the difference: now students on both sides of the building performed at the same level. A whole host of subsequent studies have shown that noise can hurt concentration and performance. Even if the impact of noise does not surprise you, the size of the impact (a full school year level at sixth grade) should. In fact, these results mirror many laboratory studies that have documented the powerful effects of even slight distraction.
    Now picture yourself working in a pleasant, quiet office: no disruptions,no trains. Instead, you are struggling with your mortgage and the fact that freelance work is hard to come by. Your spouse and you are living a two-earner life with only one and a quarter earners. You sit down to focus on your work. Soon your mind is wandering.
Should we sell the second car? Should we take another loan?
Suddenly, that quiet office is not so quiet anymore. These noisy trains of thought are every bit as hard to ignore. They arrive at even greater regularity and are every bit as uninvited. But these trains pull you on board.
Should we sell the second car?
leads to
That would raise some money, but it would make the logistics so much harder, just when I need to be working as hard as I can. We don’t want to risk the one steady job we do have
. You can ride these trains of thought for some time before you break free and return to focusing on your task. Though this room seems quiet, it is full of disruptions—disruptions that come from within.
    This is how scarcity taxes bandwidth. The things that distract us, that occupy our mind, need not come from outside us. We often generate them for ourselves, and these distractions can disrupt our attention more than a physical train. These trains of thought rumble with personal relevance. The mortgage distraction lingers because it matters. It is not a passing nuisance but an intensely personal concern. It is a distraction precisely because it causes us to tunnel. The persistent concern pulls at the mind, drawing us in. Just like an external noise that distracts us from thinking clearly, scarcity generates
internal
disruption.
    The notion of an “internal disruption” is commonplace in the cognitive sciences and in neuroscience. A great many studies have documented the profound impact of internal thoughts—even something as trivial as rehearsing a sequence of numbers in your head—on general cognitive function. And years of lab studies compounded by fMRI