• This is why that friend from back home is a welcome companion in Prague. (Finally! Someone else who speaks English and can talk about the Superbowl!) It’s also why that same friend is less interesting when you get back home, where there are people whose interests are more aligned with yours.

• Cognitive neuroscience says we should externalize information in order to clear the mind. This is why Robert Shapiro and Craig Kallman keep contact files with contextual information such as where they met someone new, what they talked about, or who introduced them. In addition, little tags or notes in the file can help to organize entries—work friends, school friends, childhood friends, best friends, acquaintances, friends of friends—and there’s no reason you can’t put multiple tags in an entry. In an electronic database, you don’t need to sort the entries, you can simply search for any that contain the keyword you’re interested in.

• The part of external memory that includes other people is technically known as transactive memory, and includes the knowledge of who in your social network possesses the knowledge you seek—knowing, for example, that if you lost Jeffrey’s cell phone number, you can get it from his wife, Pam, or children, Ryder and Aaron.

• Not surprisingly, men and women have different images of what intimacy entails: Women are more focused than men on commitment and continuity of communication, men on sexual and physical closeness.

• This cognitive illusion is so powerful it has a name: the fundamental attribution error. An additional part of the fundamental attribution error is that we fail to appreciate that the roles people are forced to play in certain situations constrain their behavior.

• Planning and doing require separate parts of the brain. To be both a boss and a worker, one needs to form and maintain multiple, hierarchically organized attentional sets and then bounce back and forth between them. It’s the central executive in your brain that notices that the floor is dirty. It forms an executive attentional set for “mop the floor” and then constructs a worker attentional set for doing the actual mopping. The executive set cares only that the job is done and is done well.

• That middle-of-the-night waking might have evolved to help ward off nocturnal predators. Bimodal sleep appears to be a biological norm that was subverted by the invention of artificial light, and there is scientific evidence that the bimodal sleep-plus-nap regime is healthier and promotes greater life satisfaction, efficiency, and performance.

• AVERAGE SLEEP NEEDS Age Needed sleep Newborns (0–2 months) 12–18 hours Infants (3–11 months) 14–15 hours Toddlers (1–3 years) 12–14 hours Preschoolers (3–5 years) 11–13 hours Children (5–10 years) 10–11 hours Preteens and Teenagers (10–17) 8 1/2–9 1/4 hours Adults 6–10 hours

• There is one mistake that many of us make when we have a looming deadline for a big project, a project that is very important and will take many many hours or days or weeks to complete. The tendency is to put everything else on hold and devote all our time to that big project—it seems as though every minute counts. But doing this means that lots of little tasks will go undone, only to pile up and create problems for you later. You know you should be attending to them, a little voice in your head or entry on your To Do list nags at you; it takes a great deal of conscious effort to not do them. This carries a tangible psychological strain as your brain keeps trying to tamp them down in your consciousness, and you end up using more mental energy to not do them than you would have used to do them.

• If you calculate what your time is worth to you, it simplifies a great deal of decision-making because you don’t have to reassess each individual situation. You just follow your rule: “If I can spend $XX and save an hour of my time, it is worth it.” Of course this assumes that the activity is something you don’t find pleasurable. If you like steam-cleaning carpets and standing in airport lines, then the calculation doesn’t work. But for tasks or chores about which you are indifferent, having a time-value rule of thumb is very helpful.

• The base rate of something is the background rate of its occurrence. Most of us have an intuitive sense for this. If you bring your car to the mechanic because the engine is running rough, before even looking at it, your mechanic might say something like “It’s probably the timing—that’s what it is in ninety percent of the cars we see. It could also be a bad fuel injector, but the injectors hardly ever fail.” Your mechanic is using informed estimations of the base rate that something occurs in the world.

• The cliché in medical diagnostics is “When you hear hoofbeats, think horses, not zebras.” In other words, don’t ignore the base rate of what is most likely, given the symptoms.

• Just because there are only two choices doesn’t mean they are equally likely.

• To take an example that might be intuitively clearer, imagine you walk into your local grocery store and bump into someone without seeing them. It could either be Queen Elizabeth or not. How likely is it that it is Queen Elizabeth? Most people don’t think it is 50-50. How likely is it that the queen would be in any grocery store, let alone the one I shop at? Very unlikely.

• Let’s look at that other piece of information, the miracle drug that can cure blurritis, chlorohydroxelene, which has a 1 in 5 chance of side effects (20% side effects is not atypical for real medications). If you take the medicine, you need to compare the 1 in 5 chance of a relentlessly itchy back with the 1 in 201 chance that it will offer you a cure. Put another way, if 201 people take the drug, only 1 of them will experience a cure (because 200 who are prescribed the drug don’t actually have the disease—yikes!). Now, of those same 201 people who take the drug, 1 in 5, or 40, will experience the side effect. So 40 people end up with that back itch they can’t reach, for every 1 person who is cured. Therefore, if you take the drug, you are 40 times more likely to experience the side effect than the cure. Unfortunately, these numbers are typical of modern health care in the United States. Is it any wonder that costs are skyrocketing and out of control?

• As one put it, “We don’t mention these complications to patients because they might be discouraged from getting the biopsy, which is a very important procedure for them to have.” This is the kind of paternalism that many of us dislike from doctors, and it also violates the core principle of informed consent.

• I explained that each biopsy represented an independent event, and that two biopsies presented a greater risk than one. None of them were buying it. The first of my conversations went like this: “I read that the risk of serious complications from the biopsy is five percent.” “That’s right.” “So if a patient has biopsies five times, that increases their risk to nearly twenty-five percent.” “You can’t just add the probabilities together.” “I agree, you can’t. You need to use the binomial theorem, and you come up with twenty-three percent—very close to twenty-five percent.” “I’ve never heard of the binomial theorem and I’m sure it doesn’t apply here. I don’t expect you to understand this. It requires statistical training.” “Well, I’ve had some statistical training. I think I can understand.” “What is it you do for a living again?” “I’m a research scientist—a neuroscientist. I lecture in our graduate statistics courses and I’ve published some statistical methods papers.” “But you’re not an MD like I am. The problem with you is that you don’t understand medicine. You see, medical statistics are different from other statistics.” “What?”

• To be fair, saying that there is no evidence does not mean that the treatment is ineffective; it simply means its effectiveness has not yet been demonstrated—we are agnostic. But the very name “alternative medicine” is misleading. It is alternative but it is not medicine (which begs the question What is it an alternative to?).

• Homeopathy is pseudoscience because (a) it doesn’t stand up to controlled experiments, (b) it uses the language of science such as dilution and molecule, and (c) it makes no sense within a scientific understanding of cause and effect.

• Our brains evidently have evolved to focus on the upper left cell, the hits, and remember nothing else. One of my former teachers, Paul Slovic, dubbed this denominator neglect. Slovic

• My friend heard about a doctor specializing in alternative medicine. The doctor did extensive “alternative” blood tests and as a result prescribed a very specific diet and exercise. The list of permitted and forbidden foods was so restrictive, it would take my friend three or four hours a day just to prepare his meals. He followed the diet and exercise program with the same kind of commitment and focus he had applied to every aspect of his life, the kind of discipline that had led him to become the president of a well-known international company when he was only thirty-eight years old.

• Thousands of people die in the United States every year from diseases that were preventable or curable with “Western medicine.” The scientific method has brought civilization further in the last two hundred years than all other methods over the previous ten thousand years. Medical researchers understand that patients’ lives are at stake in their experiments—often, even before a clinical trial is completed, scientists will see a clear benefit and call off the trial early in order to make the medicine available sooner rather than make patients wait, some of whom are so sick that waiting is not an option.

• A medical minimalist tries to interact with medicine and doctors as little as possible. A maximalist thinks every problem, every ache and pain, has a medical solution. A naturalist believes the body can cure itself, perhaps with the aid of plant-based and spiritual remedies. A technologist believes there are always new drugs or procedures that are better than anything that came before them, and that they will be the most effective route

• In any hierarchically organized firm or agency, the task of carrying out the company’s objectives typically falls to the people at the lowest levels of the hierarchy. Cell phones aren’t built by the engineer who designed them or the executive who is in charge of marketing and selling them but by technicians on an assembly line. A fire isn’t put out by the fire chief but by the coordinated efforts of a team of firefighters on the street. While managers and administrators do not typically do the main work of a company, they play an essential role in accomplishing the company’s objectives. Even though it is the machine gunner and not the major who fights battles, the major is likely to have a greater influence on the outcome of a battle than any single machine gunner.

• If we can predict some (but not all) aspects of how a job will go, we find it rewarding. If we can predict all aspects of the job, down to the tiniest minutiae, it tends to be boring because there is nothing new and no opportunity to apply the discretion and judgment that management consultants and the U.S. Army have justly identified as components to finding one’s work meaningful and satisfying. If some but not too many aspects of the job are surprising in interesting ways, this can lead to a sense of discovery and self-growth.

• The composers widely regarded as among the most creative in musical history fit this description of balancing creativity within constraints. Mozart didn’t invent the symphony (Torelli and Scarlatti are credited with that) and The Beatles didn’t invent rock ’n’ roll (Chuck Berry and Little Richard get the credit, but its roots go back clearly to Ike Turner and Jackie Brenston in 1951, Louis Jordan and Lionel Hampton in the 1940s). It’s what Mozart and The Beatles did within the tight constraints of those forms, the enormous creativity and ingenuity they brought to their work, that pushed at the boundaries of those forms, leading to them being redefined.

• The key to this working is to keep it stocked up. Don’t raid it if you’re home—it is sacrosanct! Along the same lines, seasoned business travelers assemble a little emergency food pack: nuts, dried fruit, PowerBar. And they assemble a toilet kit with duplicates so that they’re not having to pack stuff from the bathroom in the rush and haze right before a trip—that’s how things get forgotten.

• One difficulty with preparing a neutral news story is that there can be many subtleties and nuances, many parts of the story that don’t fit neatly into a brief summary. The choice about what parts of an article to leave out—elements that complicate the story—is just as important as deciding what to include, and the conscious or subconscious biases of the writers and editors can come into play in this selection.

• Consider that in this particular case, you’re seeing only those letters he chose to send you—you’re not seeing the letters he sent to anyone else. Statisticians call this selective windowing. The case I’m describing actually occurred, and the broker was imprisoned for fraud. At the beginning of the whole scheme, he sent out two sets of letters: One thousand people received a letter predicting that IBM stock would go up, and one thousand received a letter predicting that it would go down. At the end of the month, he simply waits to see what happens. If IBM went down, he forgets about the thousand people who received a wrong prediction, and he sends follow-up letters only to those thousand who received the correct prediction. He tells half of them that Dow Chemical will go up and he tells the other half that Dow Chemical will go down. After six iterations of this, he’s got a core group of thirty-one people who have received six correct predictions in a row, and who are ready to follow him anywhere.

• The Gricean maxim of relevance implies that no one would construct such a graph (below) unless they felt these two were related, but this is where critical thinking comes in. The graph shows that they are correlated, but not that one causes the other. You could spin an ad hoc theory—pirates can’t stand heat, and so, as the oceans became warmer, they sought other employment. Examples such as this demonstrate the folly of failing to separate correlation from causation.

• Consider an alternative account, championed by the scientist (and smoker) Hans Eysenck. He has proposed that there is a certain personality type that is prone to smoking. This seems reasonable. Now suppose that there is a gene associated with this personality type and also associated with a propensity to get lung cancer. The gene becomes a third factor x—it increases the likelihood that people will take up smoking and it also increases the likelihood that they’ll get lung cancer. Note that if this is true, those people would have gotten lung cancer whether or not they smoked—but because the gene causes them to smoke, we’ll never know for sure if they would have contracted lung cancer without smoking. Few scientists take this view seriously, but it is possible that Eysenck is right.

• If someone says that 400 million people voted in the last U.S. federal election, that a new economy car has a top speed of four hundred miles per hour, or that so-and-so lost fifty pounds in two days with a juice fast, your general knowledge of the world and your inherent numeracy should raise a red flag about these numerical values.

• George Polya, in his influential book How to Solve It, showed how the average person can solve complicated mathematical problems without specific training in math. The same is true for this class of crazy, unknowable problems.

• Everything Else The Power of the Junk Drawer To many people, being organized means “a place for everything and everything in its place.” This is an important principle for organizing files, tools, objects in the home and office, and so on. But it’s equally important for our organizational systems and infrastructure to allow for fuzzy categories, for things that fall through the cracks—the miscellaneous folder in your filing system, the junk drawer in your kitchen. As Doug Merrill says, organization gives us the freedom to be a bit disorganized. A typical American kitchen junk drawer holds pens, matches, slips of paper, maybe a hammer, chopsticks, a tape measure, picture hooks. There are certain design constraints at work that legitimize a catchall drawer: You’re not going to redesign the kitchen just to have a small drawer or cubby for chopsticks and another for matches. The junk drawer is a place where things collect until you have time to organize them, or because there is no better place for them. Sometimes what looks like a mess may not have to be physically reorganized at all, if you can slow down and observe the organization in the thicket of details.

• Take the numbering of the U.S. Interstate Highway System. On the surface, it may look like a mess, but in fact it’s a hightly organized system. It was initiated by President Dwight D. Eisenhower and construction began in 1956. Today, it comprises nearly 50,000 miles of roadway. The numbering of interstate highways follows a set of simple rules. If you know the rules, it is easier to figure out where you are (and harder to get lost) because the rules off-load information from your memory and put it into a system that is out-there-in-the-world. In other words, you don’t need to memorize a set of seemingly arbitrary facts such as Highway 5 runs north-south or Highway 20 runs east-west in the southern part of the country. Instead, you learn a set of rules that applies to all the numbers, and then the highway numbers themselves tell you how they run:

• The elegance of the periodic table is difficult to duplicate but worth trying, even in rather mundane settings. A machine shop that organizes taps and dies, or nuts and bolts, along two dimensions of length and width can easily find gaps in the collection where items are missing. The systematic organization also makes it easy to notice misfiled items.

• The three books of Thus Spake Zarathustra by Friedrich Nietzsche were composed in three separate ten-day bursts of inspiration.

• But many of us still find something soothing and satisfying about handling physical objects. Memory is multidimensional, and our memories for objects are based on multiple attributes. Think back to your experience with file folders, the physical kind. You might have had an old beat-up one that didn’t look like the others and that—quite apart from what was inside it or written on it—evoked your memories of what was in it. Physical objects tend to look different from one another in a way that computer files don’t. All bits are created equal. The same 0s and 1s on your computer that render junk mail also render the sublime beauty of Mahler’s fifth symphony, Monet’s Water Lilies, or a video of a Boston terrier wearing reindeer antlers. There is nothing in the medium itself that carries a clue to the message. So much so that if you looked at the digital representation of any of these—or this paragraph, for example—you would not even know that those zeros and ones were representing images rather than text or music. Information has thus become separated from meaning.

• Many scientific careers were fueled by ideas that came to researchers by stumbling upon articles that captured their attention while searching for something else that turned out to be far more boring and less useful. Many students today do not know the pleasure of serendipity that comes from browsing through stacks of old academic journals, turning past “irrelevant” articles on the way to the one they’re looking for, finding their brain attracted to a particularly interesting graph or title. Instead, they insert the name of the journal article they want and the computer delivers it to them with surgical precision, effortlessly. Efficient, yes. Inspiring, and capable of unlocking creative potential, not so much.

• There are really only two strategies for selection in the face of this—searching and filtering. Together these can be more parsimoniously thought of as one strategy, filtering, and the only variable is who does the filtering, you or someone else. When you search for something, you start out with an idea of what you want, and you go out and try to find it. In the Internet age, “go out” may not be more than typing a few keystrokes on your laptop while you sit propped up in bed with your slippers on, but you are effectively going out into the digital world to find what you’re looking for. (Computer scientists call this pull because you are pulling information from the Internet, as opposed to push, where the Internet automatically sends information to you.) You or your search engine filter and prioritize the results, and if all goes well, you have what you’re looking for instantly. We tend not to keep a copy of it, virtual or physical, because we know it will be there later for us when we need it. No curating, no collecting, and no serendipity.

• As with Einstein, the key to the NCI initiative is that nonlinear, creative thinking be tethered to rational, linear thinking in order to implement it in the most robust and rigorous way possible—the dreams of men and women paired with the vast resources of computers. Paul Otellini, the recently retired CEO of Intel, puts it this way:

• When I arrived at Intel, the possibility that computers would shape all these aspects of our lives was science fiction. … Can technology solve our problems? Think what the world would be like if Moore’s law, the equation that characterizes the tremendous growth of the computing industry, were applied to any other industry. Take the auto industry. Cars would get half a million miles per gallon, go 300,000 mph, and it would be cheaper to throw away a Rolls Royce than to park it.