Not Born Yesterday

by Hugo Mercier

  trust, and to make promises credible. This doesn’t quite mean

  that people trust blindly, as such cheap promises lose some of

  their power when the stakes increase.29

  Social scientist Toshio Yamagishi highlighted another advan-

  tage from trusting even when short- term rationality dictates we

  shouldn’t, pointing out a fundamental asymmetry between trust-

  ing and not trusting in terms of information gains.30 If you

  choose to trust someone, more often than not you’ll be able to

  tell whether your trust was warranted. If a new classmate asks to

  borrow your notes and promises to give them back to you the

  next day, you’ll only know if they’ll keep their word if you

  lend them the notes. By contrast, if you don’t trust someone,

  you might never know whether they would in fact have been

  a n g r y p und i t s a nd sk il l f ul c o n me n 253

  trustworthy. If a friend tries to set you up with someone you

  don’t know, it’s only if you follow the dating advice that you’ll

  figure out whether or not it was solid.

  Admittedly, there are situations in which we can gauge the

  value of someone’s word without having to trust them first. For

  instance, you can see whether investment advice pans out with-

  out following it, simply by keeping track of the relevant stocks.

  Stil , as a rule, we learn more by trusting than by not trusting.

  Trust is like any other skil : practice makes perfect.

  As a result of this asymmetry between trusting and mistrust-

  ing, the more we trust, the more information we gain. We not

  only know better which specific individuals are trustworthy but

  also use these experiences to figure out what kind of individual,

  in what kind of situation, should be trusted. In a series of experi-

  ments, Yamagishi and his colleagues found that the most trust-

  ful of their participants— those more likely to think that other

  people could be trusted— were also the best at ascertaining who

  should be trusted (in games analogous to the trust game).31 Like-

  wise, people who are the least trusting are the least able to dis-

  criminate between phishing attempts and legitimate interfaces.32

  My maternal grandparents are the best illustration I know of

  Yamagishi’s ideas. On the surface, they might seem like easy prey:

  they aren’t so young anymore (being in their early nineties at the

  time of this writing), they are supernice, and are always there

  when a friend or a neighbor (or indeed my wife and I) need

  something. One doesn’t get much more grandmotherly than my

  grand mother, plying children with sweets and giving big hugs.

  Yet my grandparents have a very shrewd judgment, skil fully ap-

  plying selective trust. I have never seen them fall for any mar-

  keting stunt, and all their friends are perfectly trustworthy. By

  giving people the benefit of the doubt in initial interactions with

  little risk, they have accumulated a wealth of knowledge about

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  who can be trusted and have met enough people that they could

  afford to select the most reliable as friends.

  In spite of the informational gains that can be accrued from

  trusting when in doubt, the general logic of open vigilance

  mechanisms suggests that, on the whole, we make more errors

  of omission (not trusting when we should) than of commis-

  sion (trusting when we shouldn’t). This might seem counter-

  intuitive, but beware the sampling bias: we’re much more

  likely to realize we shouldn’t have trusted someone when we

  did (we follow our friend’s advice and end up on a horrible

  date) than to realize we should have trusted someone when

  we didn’t (we don’t follow our friend’s advice and fail to meet

  our soul mate). The main issue with using coarse cues isn’t that

  we trust people we shouldn’t (trusting a con man because he’s

  dressed as a respectable businessman), but that we don’t trust

  people we should (mistrusting someone because of their skin

  color, clothing, accent, etc., when in fact they are perfectly

  trustworthy).

  Experiments with economic games support this prediction.

  Economists Chaim Fershtman and Uri Gneezy asked Jewish par-

  ticipants in Israel to play trust games.33 Some of the participants

  were Ashkenazi Jews (mostly coming from Eu rope and the

  United States); others were Eastern Jews (mostly coming from

  Africa and Asia). By and large, the former group had higher sta-

  tus and was expected to be perceived as more trustworthy. This

  is indeed what Fershtman and Gneezy observed. In a trust game,

  male investors transferred more money to Ashkenazi trustees

  than to Eastern trustees. However, the relative mistrust of the

  Eastern Jews was unwarranted, as Ashkenazi and Eastern trust-

  ees returned similar amounts. The same pattern was observed

  by economist Justine Burns in South Africa.34 In her experiment,

  investors transferred less money to black trustees than to other

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  trustees, even though black trustees then returned as much

  money.35 In these experiments at least, the participants would

  have been better off recalibrating their coarse cues and trusting

  more these ethnic groups.

  What to Do?

  How can we better calibrate our trust? The two trust calibration

  mechanisms I have explored here are quite distinct and call for

  diff er ent adjustments. When it comes to the taking- sides strat-

  egy, we should be aware that it can be abused by people who

  claim to be on our side but aren’t actually paying any cost for their

  commitment. We should be wary of largely made-up controver-

  sies with largely made-up enemies. If we base our repre sen ta-

  tion of the other side on how it is portrayed in the news or, worse,

  on social media, then this repre sen ta tion is likely to be wide off

  the mark— mistaking, say, crazy conspiracy theorists for average

  Republicans, or enraged social justice warriors for typical Demo-

  crats. We must remind ourselves that the members of the “other

  side” are prob ably not that diff er ent from us, and that engaging

  with them is worthwhile.

  What about coarse cues? When we have to rely on coarse

  cues— for example, when we meet someone for the first

  time— I believe we should try to worry less about how people

  judge our decisions to trust or not to trust. Con men and social

  engineers often rely on our reluctance to question our inter-

  locutors, our fear of appearing rude because we don’t trust

  them. After all, if you meet someone who really is a long- lost

  acquaintance, and you suggest they are trying to scam you, they

  will be justifiably annoyed. Not wishing to be thought ill of also

  drives some of our misplaced mistrust, as we’re afraid of looking

  like fools if we get played.

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  In both instances we should strive to resist these social pres-

  sures. The long- lost acquaintance shouldn’t put us in a situation

  in which we have to immediately
trust them with something sig-

  nificant (like an expensive watch). If they do, they are the ones

  who are breaking social norms, not us when we refuse to grant

  trust under pressure. As for the fear of looking like we’re easily

  tricked, we should strive to remember the information we gain

  by trusting people, even when our trust doesn’t pan out. As long

  as we start small, trusting people quite broadly is a decision that

  should pay off in the long run, with the occasional failure a mere

  cost of doing business. To compensate for when we trust too

  much, we should consider the costs of failing to trust, the myr-

  iad mutually beneficial relationships we could have formed if we

  had trusted more people.

  16

  THE CASE AGAINST GULLIBILITY

  this book is a long argument against the idea that humans

  are gullible, that they are “wired not to seek truth” and “overly

  deferential to authority,” and that they “cower before uniform

  opinion.”1 If gullibility appears to have some advantages, allow-

  ing us to learn more easily from our elders and our peers, the

  costs are just too high. The theory of the evolution of commu-

  nication dictates that for communication to exist, both senders

  and receivers must benefit from it. If receivers were excessively

  gullible, they would be mercilessly abused by senders, until they

  reached a point where they simply stopped paying any attention

  to what they were being told.

  Far from being gullible, we are endowed with a suite of cogni-

  tive mechanisms that evaluate what we hear or read. These mech-

  anisms allow us to be open—we listen to information deemed

  valuable— and vigilant—we reject most harmful messages. As

  these open vigilance mechanisms grew increasingly complex, we

  paid attention to more cues tel ing us that others are right and we

  are wrong. We let ourselves be influenced by others more and

  more, going from the fairly limited communicative powers of our

  pre de ces sors to the infinitely complex and power ful ideas that

  human language lets us express.

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  258 ch ap t er 16

  This evolution is reflected in the organ ization of our minds.

  People deprived of the most sophisticated means of evaluating

  information— through brainwashing, subliminal influence, or

  mere distraction— cannot pro cess the cues tel ing them to ac-

  cept new, challenging messages. They revert to a conservative

  core, rejecting anything they don’t already agree with, being

  much harder, not much easier, to influence.

  Open vigilance mechanisms are part of our common cogni-

  tive endowment. Their roots can be found in toddlers or even

  infants. Twelve- month- old infants integrate what they are told

  with their prior opinions, so that they are easiest to influence when

  their opinions are weak, and are very stubborn other wise—as

  anyone who has interacted with a one- year- old will be painful y

  aware.2 Infants this age also track the actions of adults and are more

  influenced by those who behave competently.3 Two- and- a- half-

  year- olds listen more to speakers who offer sound rather than

  circular arguments.4 At three years of age, toddlers put more trust

  in someone who is reporting what they have seen rather than

  guessed, and they have figured out who is an expert in familiar

  domain, such as food and toys.5 When they turn four, preschool-

  ers get a grasp of how best to follow the majority opinion, and

  they discount agreement based on mere hearsay.6

  Our open vigilance mechanisms are for learning, and figur-

  ing out what to believe and who to trust doesn’t stop at four years

  of age. It never stops: as we accumulate knowledge and experi-

  ence, we constantly sharpen our open vigilance mechanisms. As

  an adult, think of how many factors you effortlessly weigh when

  evaluating the most mundane communication. If your colleague

  Bao says, “You should switch to the new OS; they’ve fixed a

  major security flaw,” your reaction will depend on the following:

  what you already know about the new OS (have you heard it seri-

  ously slows computers down?), how vulnerable you think your

  t he c a se a g a ins t g ul l ib il i t y 259

  computer is to attacks (is the security flaw really major?), what

  Bao’s level of competence in this domain is compared with

  yours (is she the IT specialist?), and whether you believe Bao

  might have any ulterior motive (might she want you to install

  the new OS so she can see whether it works well?). None of

  these kinds of calculations have to be conscious, but they are

  going on whenever we hear or read something.

  In everyday life, when interacting with people we know, cues

  tel ing us to change our minds abound: we have time to ascertain

  goodwil , recognize expertise, and exchange arguments. By con-

  trast, these cues are typically absent from mass persuasion contexts.

  How can a government agency build trust? How can politicians

  display their competence to those who don’t closely follow poli-

  tics? How can an advertising campaign convince you a given

  product is worth buying? Mass persuasion should be tremen-

  dously difficult. Indeed, the vast majority of mass persuasion

  efforts, from propaganda to po liti cal campaigns, from religious

  proselytizing to advertising, end in abject failure. The (modest)

  successes of mass persuasion are also well accounted for by the

  functioning of our open vigilance mechanisms. The conclusion

  reached by Ian Kershaw with re spect to Nazi propaganda applies

  more broadly: the effectiveness of mass persuasion is “heavi ly

  dependent on its ability to build on existing consensus, to con-

  firm existing values, to bolster existing prejudices.”7 This reflects

  the working of plausibility checking, which is always operating,

  making even the most successful mass persuasion efforts some-

  what inert: people might accept the messages, but the messages

  do not substantially affect their preexisting plans or beliefs. In

  some situations, when some trust has been built, mass persua-

  sion can change minds, but then only on issues of little personal

  import, as when people follow po liti cal leaders on topics in

  which they have little interest and even less knowledge.

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  How to Be Wrong without Being Gullible

  If the successes of mass persuasion are, more often than not, a

  figment of the popu lar imagination, the dissemination of empiri-

  cally dubious beliefs is not. We all have, at some point in our

  lives, endorsed one type of misconception or another, believing

  in anything from wild rumors about politicians to the dangers

  of vaccination, conspiracy theories, or a flat earth. Yet the suc-

  cess of these misconceptions is not necessarily a symptom of

  gullibility.

  The spread of most misconceptions is explained by their in-

  tuitively appealing content, rather than by the skil s of those who

  propound them. Vaccine hesitancy surfs on the counterintuitive-


  ness of vaccination. Conspiracy theories depend on our justi-

  fied fear of power ful enemy co ali tions. Even flat- earthers argue

  that you just have to follow your intuition when you look at the

  horizon and fail to see any curvature.

  Even though many misconceptions have an intuitive dimen-

  sion, most remain cut off from the rest of our cognition: they

  are reflective beliefs with little consequences for our other

  thoughts, and limited effects on our actions. The 9/11 truthers

  might believe the CIA is power ful enough to take down the

  World Trade Center, but they aren’t afraid it could easily silence

  a blabbing blogger. Most of those who accused Hil ary Clinton’s

  aides of pedophilia were content with leaving one- star reviews

  of the restaurant in which the children were supposedly abused.

  Even forcefully held religious or scientific beliefs, from god’s om-

  niscience to relativity theory, do not deeply affect how we

  think: Christians still act as if god were an agent who could only

  pay attention to one thing at a time, and physicists can barely

  intuit the relationship between time and speed dictated by Ein-

  stein’s theories.

  t he c a se a g a ins t g ul l ib il i t y 261

  If some of these reflective beliefs are counterintuitive—an

  omniscient god, the influence of speed on time— I have ar-

  gued that most have an intuitive dimension, such as vaccine

  hesitancy, conspiracy theories, or a flat earth. How can a belief

  be both reflective (separated from most of our cognition) and

  intuitive (tapping into a number of our cognitive mecha-

  nisms)? Take the belief in a flat earth. Imagine you have no

  knowledge of astronomy. Someone tel s you that the stuff you’re

  standing on, the stuff you see, is called the earth. So far so good.

  Now they either tell you that the earth is flat, which fits with

  what you perceive, or that it is spherical, which doesn’t. The

  first alternative is more intuitively compel ing. Stil , even if you

  now accept that the earth is flat, the belief remains largely re-

  flective, as you aren’t quite sure what to do with the concept of

  “earth.” Unless you’re about to embark on a very long journey,

  or have to perform some astronomical calculations, your ideas

  about the shape of the earth have no cognitive or practical

  consequences.