Not Born Yesterday

by Hugo Mercier

  62 ch ap t er 4

  checking, when it happens to work with poor material. When

  more accurate views—in evolution by natu ral se lection, in the

  efficacy of vaccines, and so forth— spread, it is in part thanks to

  argumentation, but argumentation is most power ful among

  people who can discuss issues at length and share a lot of com-

  mon ground. For these sound beliefs to expend outside of a circle

  of experts, we must be able to recognize that sometimes others

  know better.

  5

  WHO KNOWS BEST?

  on january 5, 2013, Sabine Moreau, resident of the small Bel-

  gian town of Erquelinnes, was supposed to pick up a friend at the

  train station in Brussels, fifty miles away. She punched the ad-

  dress in her satnav and started driving. Two days and eight

  hundred miles later she had reached Zagreb, on the other side

  of Eu rope, having crossed three countries on the way. That was

  when she de cided that something must be wrong, made a U- turn,

  and found her way back to Erquelinnes.1

  As I argued in the last chapter, we put more weight on our own

  beliefs than on communicated information— when every thing

  else is equal. Every thing else often isn’t equal. Others can be

  ignorant, mistaken, or poorly informed, giving us reasons to

  discount their opinions. But others can also be more competent

  and better informed. A major part of the open- mindedness of

  open vigilance mechanisms comes from being able to identify,

  and then listen to, those people who know better, overcoming

  our initial reaction driven by plausibility checking to reject infor-

  mation that conflicts with our prior beliefs.

  In this chapter, I explore a variety of cues that help us identify

  who knows best: Who has had the best access to information?

  Who has a history of getting things right? Whose opinion is

  shared by the most people?

  63

  64 ch ap t er 5

  These cues told Sabine Moreau she should believe her satnav.

  The satnav has access to precise maps, had proven reliable over

  many past trips, and is widely believed to be accurate. Obviously,

  she went too far in letting these cues trump her intuitions. But for

  one Sabine Moreau, how many people end up lost or stuck in traf-

  fic jams because they didn’t follow their satnav’s suggestions?

  Eyewitness Advantage

  The most obvious cue that someone else is more likely than us

  to be right is access to a sound source of information. You be-

  lieve that your friend Paula is not pregnant. Bil , who you know

  has just seen Paula, tel s you not only that she is but also that she

  is quite far along in her pregnancy. Assuming you have no rea-

  son to think Bill is lying to you (a question we turn to in the next

  chapter), you should change your mind and accept that Paula is

  pregnant. Testimony from the right source can also amount to

  privileged access—if you know Bill has just called Paula, you

  should also believe him when he tel s you she is pregnant.

  Intuitions about the value of informational access develop

  very early. In a classic study, psychologist Elizabeth Robinson and

  her colleagues systematically varied the information

  children— some as young as three— had about what was in a

  box.2 Some children saw what was in the box; others simply

  guessed. The children were then confronted by an adult who told

  them that what was in the box was diff er ent from what the

  children had just said. Like the children, some of the adults had

  seen what was in the box, and others had just guessed. The

  children were most likely to believe the adult when she had seen

  what was in the box, while they had only guessed; the children

  were least likely to believe the adult when she had guessed what

  was in the box, while they had seen it.

  w h o k n o w s b e s t ? 65

  If we do not already know what information our interlocutors

  have had access to, they often tell us. If Bill knows you think Paula

  isn’t pregnant, he might preempt your doubts by saying, “Paula

  just told me she’s pregnant.” Such information about the source

  of our beliefs is ubiquitous in conversation. Even when none is

  mentioned explic itly, some can usually be inferred. If Bill tel s

  you “That movie is great!,” this suggests he saw the movie rather

  than, say, read some reviews.

  Again, even young children are sensitive to such reported in-

  formational access. In a series of experiments, my colleagues

  and I asked preschoolers to help a (toy) girl find her lost (toy)

  dog. A (toy) woman suggested the dog had gone in one direc-

  tion, saying that she had seen it go that way. Another (toy)

  woman pointed to a diff er ent direction, without specifying why

  she believed this to be the right place to look for the dog. The

  children were more likely to believe the woman mentioning

  a reliable access to information, and the same was true when

  the second woman provided a bad reason rather than no rea-

  son at all.3

  Reliable Expertise

  When a friend offers a way of fixing our computer prob lems, rec-

  ommends a restaurant, or provides dating advice, it is not

  enough to know where she got her ideas from. Maybe she had

  firsthand experience of the restaurant, but the value of that

  experience depends on her taste in food—if she can’t tell a

  McDonald’s from a Michelin-starred restaurant, her firsthand

  experience isn’t worth much. How can we figure out who is

  competent in what domain?

  The most reliable cue is past per for mance. If someone

  has been consistently able to solve computer prob lems, pick

  66 ch ap t er 5

  exquisite restaurants, or give sound dating advice, then it is

  prob ably worth listening to what they’re saying in each of these

  domains.

  From an evolutionary point of view, what makes past per for-

  mance a great cue is that it is hard or impossible to fake. It is

  difficult to consistently solve computer prob lems, find exquisite

  restaurants, and give sound dating advice if you don’t possess

  some under lying skill or knowledge that allows you to keep per-

  forming well in these areas.

  To evaluate others’ per for mance, we can rely on a wide vari-

  ety of cognitive devices. Humans are equipped with mechanisms

  for understanding what other people want, believe, and intend.

  Thanks to these mind- reading mechanisms, we can understand,

  say, that our friend wants her computer to work again. All we have

  to do, then, is keep track of whether she successfully reaches

  her goal.

  We can also rely on the mechanisms described in the last chap-

  ter: plausibility checking and reasoning. Someone who gives

  you the right answer to an insight prob lem (like the one with the

  triplets) or who offers a novel and convincing mathematical dem-

  onstration should be deemed more competent, at least in these

  domains.4

  Seeing someone, from a professional athlete to a craftsperson,

&nbs
p; do something well can be very pleas ur able, giving rise to so- cal ed

  competence porn— for example, the consistently articulate and

  witty exchanges of screenwriter Aaron Sorkin’s protagonists. The

  plea sure we derive from watching someone perform flawlessly

  actions that do not benefit us directly is likely related to the

  learning possibilities afforded.

  Having recognized who is good in what area, one possibility

  is to imitate them. Some nonhuman animals, such as the house

  w h o k n o w s b e s t ? 67

  mouse, are already selective in who they imitate, being more

  likely to copy the actions of adults than of juveniles.5 But imita-

  tion has its limits. Copying what your friend does when she

  fixes her computer prob lems is unlikely to help fix your own

  prob lem. Following your foodie friend around might lead you

  to some places that are not really to your taste, and to a depleted

  bank account. That’s when communication comes in handy.

  Once you have inferred, through past per for mance, that a given

  friend is good with computers, you can ask them about your spe-

  cific prob lem. You can request from your foodie friend recom-

  mendations that fit your taste and your bud get. Drawing on your

  friends’ expertise to get answers to your own prob lems makes

  more sense than simply imitating them.6

  Einstein or the Mechanic?

  Looking at past per for mance is a power ful strategy for establish-

  ing competence, but it is not as simple as it seems. One diffi-

  culty is that per for mance can be largely a matter of luck. A no-

  torious con temporary example is the trading of stocks in financial

  markets: it is fantastically difficult to tell whether the per for-

  mance of, say, a hedge fund is due to the intrinsic competence

  of its traders or to dumb luck.7 Even strong per for mance over

  several years is not much of an indicator: given how many hedge

  funds there are, it is statistically unavoidable that some will per-

  form well year after year through chance alone. The same logic

  applies to skills that were undoubtedly more relevant during

  earlier stages of human evolution, such as hunting large game.

  Once a given level of competence is reached, who makes the kil

  on any given day is partly a matter of luck, making it difficult to

  assess the hunters’ individual competence.8

  68 ch ap t er 5

  Fortunately, per for mance in many domains— fixing computers,

  say—is less erratic.9 But even when per for mance can reliably

  be detected, an issue persists: How do we generalize from ob-

  served per for mance to under lying competence? When your

  friend fixes the printer prob lem on her computer, what should

  you infer? We intuitively discard some options: that she is good

  at fixing things on Mondays, at fixing gray things, or at fixing

  things on tables. But that leaves a wide array of plausible possi-

  bilities: that she’s good at fixing printer prob lems on her com-

  puter, fixing prob lems on her computer, fixing printer prob lems,

  fixing Macs, fixing computers, fixing electronics, fixing things,

  understanding complex prob lems, or following instructions.

  The fact is that psychologists do not know how people should

  generalize from observed per for mance to under lying compe-

  tence. Some psychologists argue that competence on many

  cognitive tasks is related through IQ. Others think we have

  diff er ent kinds of intel igences. Robert Sternberg, for example,

  has developed a theory of three aspects of intel igence: analytic

  skil s, creativity, and practical skil s. Howard Gardner argues for

  eight or nine modalities of intelligence, ranging from visual-

  spatial to bodily- kinesthetic.10 Other psychologists yet suggest

  our minds are made up of a great many specialized modules—

  from a face-recognition module to a reasoning module— and

  that the strength of these modules varies from one individual

  to the next.11

  What ever the correct answer to this complex prob lem turns

  out to be, it is clear that humans are endowed with intuitions to

  guide their inferences from per for mance to under lying compe-

  tence. These intuitions are already on display in young children.

  Preschoolers know that they should direct questions about toys

  to another child rather than an adult, and questions about food

  w h o k n o w s b e s t ? 69

  to an adult rather than a child.12 When they are asked who knows

  more about how elevators work, preschoolers pick a mechanic

  over a doctor, while they pick a doctor over a mechanic when

  asked who knows more about why plants need sunlight to

  grow.13

  Adults also appear to be quite good at telling who is good

  at what. As we saw earlier, intraindividual variability in hunt-

  ing per for mance means that sustained observation over long

  periods of time is necessary to tell who is the best hunter. Yet

  people are capable of such observations. When Hadza— a

  group of traditional hunter- gatherers from southern Africa—

  were asked to evaluate the hunters in their community, their

  rankings correlated well with hunting per for mance (as mea-

  sured by the experimenters, for instance, by testing archery

  skills).14

  Moving from the plains of Tanzania to the pubs of South West

  England, a recent experiment asked groups of participants from

  Cornwall a series of quiz questions on a wide range of trivia prob-

  lems, from geography to art history.15 Participants were then

  asked to nominate a group member to answer, on their own,

  some bonus questions—if they answered wel , the whole group

  would benefit. Even though the participants hadn’t received any

  feedback on who had given the correct answers in the initial

  round of questions, they didn’t rely on rough heuristics, such as

  picking dominant or prestigious individuals. Instead, they were

  able to accurately select the most competent members in each

  trivia category. More significantly, research on po liti cal discus-

  sions shows that U.S. citizens are able to figure out who, among

  the people they know, is most knowledgeable about politics—

  and they are more likely to broach po liti cal topics with these

  more knowledgeable acquaintances.16

  70 ch ap t er 5

  Rational Sheep

  That a given individual knows more than we do, either because

  they have had access to better information or because they are

  more competent, is not the only cue tel ing us that other people

  might be right and we might be wrong (or simply ignorant). To

  evaluate an opinion we can look beyond the individual compe-

  tence of whoever holds it and take into account how many

  people hold it.

  Accepting something because it is the majority opinion has

  a bad press. For millennia people have been castigated for indis-

  criminately following the crowd. This distaste for majority

  opinion has led some intel ectuals to pretty extreme conclusions,

  as when phi los o pher Søren Kierkegaard claimed that “truth al-


  ways rests with the minority,”17 or Mark Twain concurred that

  “the Majority is always in the wrong.”18

  By this logic, the earth is flat and ruled by shape- shifting liz-

  ards. Without being as pessimistic as Kierkegaard or Twain, some

  experiments suggest that people put little stock in majority opin-

  ion. Take the following quiz:

  Imagine an assembly that contains ninety- nine members.

  They have to decide between two options: option 1 and op-

  tion 2. One option is better than the other, but, before the

  vote, we don’t know which.

  To decide between the two options, they use majority vot-

  ing. The ninety- nine members vote, and if one option gathers

  fifty votes or more, then it wins.

  Each member of the assembly has a 65 percent chance of

  selecting the best option.

  What do you think are the odds that the assembly selects

  the best option?

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  Martin Dockendorff, Melissa Schwartzberg, and I put this

  question and variants of it to participants in the United States.19

  On average the participants believed that the assembly was barely

  more likely than chance to select the best option. Majority vot-

  ing would thus make the assembly no more likely to select the

  best option than each individual member— quite an indictment

  of demo cratic procedures.

  In fact, there is a correct answer to this question. Its formula

  was discovered in the late eigh teenth century by the Marquis de

  Condorcet,20 an extraordinary intellectual who defended the

  French Revolution yet ended up having to kill himself to escape

  the guillotine. Thanks to the Condorcet jury theorem, we know

  that the odds of the assembly being right are in fact 98 percent

  (making a few assumptions to which I will return later).

  The power of aggregating information from many sources is

  increasingly recognized. A century after Condorcet, Francis Gal-

  ton showed how averaging across many opinions is nearly guar-

  anteed to lower the resulting error: the error of the average is

  generally lower, and never worse than the average error.21 Much

  more recently, journalist James Surowiecki bril iantly pop u lar-

  ized the “miracle of aggregation” in The Wisdom of Crowds.22 Car-

  toonist Randall Munroe made this logic intuitive with his xkcd

  “Bridge” strip (figure 2).23