Hearing is believing (Belief formation bias)

Hearing is believing

When I speak at professional conferences, I will occasionally bring up the subject of belief formation by asking the audience a question: “Who here knows how you can predict if a man will go bald?” People will raise their hands, I’ll call on someone, and they’ll say, “You look at the maternal grandfather.” Everyone nods in agreement. I’ll follow up by asking, “Does anyone know how you calculate a dog’s age in human years?” I can practically see audience members mouthing, “Multiply by seven.”

Both of these widely held beliefs aren’t actually accurate. If you search online for “common misconceptions,” the baldness myth is at the top of most lists. As Medical Daily explained in 2015, “a key gene for baldness is on the X chromosome, which you get from your mother” but “it is not the only genetic factor in play since men with bald fathers have an increased chance of going bald when compared to men whose fathers have a full set of hair. . . . [S]cientists say baldness anywhere in your family may be a sign of your own impending fate.”

As for the dog-to-human age ratio, a rough rule can acquire the authority of a precise conversion through repetition. Where did we get these beliefs? And why do they persist, despite contrary science and logic?

We form beliefs in a haphazard way, believing all sorts of things based just on what we hear out in the world but haven’t researched for ourselves.

This is how we think we form abstract beliefs:

1. We hear something;
2. We think about it and vet it, determining whether it is true or false; only after that
3. We form our belief.

Gilbert’s account suggests that we can instead form abstract beliefs this way:

1. We hear something;
2. We believe it to be true;
3. Only sometimes, later, if we have the time or the inclination, we think about it and vet it, determining whether it is, in fact, true or false.

Daniel Gilbert, known for Stumbling on Happiness, also studied belief formation. In a 1991 paper in which he summarized centuries of philosophical and scientific study on the subject, he concluded, “Findings from a multitude of research literatures converge on a single point: People are credulous creatures who find it very easy to believe and very difficult to doubt. In fact, believing is so easy, and perhaps so inevitable, that it may be more like involuntary comprehension than it is like rational assessment.”

Two years later, Gilbert and colleagues reported experiments consistent with initial acceptance of information, followed by a separate effort to reject it. The experiments tested errors when statements were labeled as false. In these experiments, subjects read a series of statements about a criminal defendant or a college student. These statements were color coded to make it clear whether they were true or false. Subjects under time pressure or who had their cognitive load increased by a minor distraction made more errors in recalling whether the statements were true or false. But the errors weren’t random. The subjects were not equally likely to ignore some statements labeled “true” as they were to rely on some statements labeled “false.” The errors were asymmetric: under pressure, participants were more likely to use false statements as if they were true. That pattern supports the proposed account; it does not mean every participant believed every statement.

This is why we believe that baldness is passed down from the maternal grandfather. If you, like me until I looked it up for this book, held that belief, had you ever researched it for yourself? When I ask my audiences this question, they generally say it is just something they heard but they have no idea where or from whom. Yet they are very confident that this is true. That gives us a reason to ask how we acquired the belief.

One possible evolutionary explanation emphasizes efficiency: accepting information quickly may sometimes be less costly than evaluating it first. Abstract belief formation (that is, beliefs outside our direct experience, conveyed through language) is likely among the few things that are uniquely human, making it relatively new in the scope of evolutionary time. Language made it possible to pass on claims about events far beyond a listener’s own experience. For perceptual beliefs from direct sensory experience, it’s reasonable to presume our senses aren’t lying. Seeing is, after all, believing. If you see a tree right in front of you, it would generally be a waste of cognitive energy to question whether the tree exists. In fact, questioning what you see or hear can get you eaten. For a threat such as a predator, a type I error (false positive) could be less costly than a type II error (false negative). In other words, better to be safe than sorry, especially when considering whether to believe that the rustling in the grass is a lion. This illustrates a possible advantage of rapid acceptance, rather than establishing the evolutionary history of belief formation.

As complex language evolved, we gained the ability to form beliefs about things we had not actually experienced for ourselves. And, as Gilbert pointed out, “nature does not start from scratch; rather, she is an inveterate jury rigger who rarely invents a new mechanism to do splendidly what an old mechanism can be modified to do tolerably well.” In this case, the system we already had was (1) experience it, (2) believe it to be true, and (3) maybe, and rarely, question it later. The proposed analogy is that secondhand information can inherit a tendency toward initial acceptance. (This is a very simple summary of a great deal of research and documentation. For some good overviews, I highly recommend Dan Gilbert’s Stumbling on Happiness, Gary Marcus’s Kluge, and Dan Kahneman’s Thinking, Fast and Slow, listed in the Selected Bibliography and Recommendations for Further Reading.)

Checking reliable sources can overturn familiar beliefs. Often, we never think to check them. (Spoiler alerts: (1) Abner Doubleday had nothing to do with inventing the game of baseball. (2) We use all parts of our brain. The 10% claim does not describe how the brain works; the counterevidence includes brain imaging and studies of brain injury. (3) Immigrants didn’t have their names Americanized, involuntarily or otherwise, at Ellis Island.)

Maybe it’s no big deal that some of these inconsequential common beliefs are clearly false. Presumably, people aren’t using a bogus dog-age calculator to make medical decisions for their pets, and veterinarians know better. But this is our general belief-formation process, and it applies in areas that can have significant consequences.

In poker, this belief-formation process can cost players a lot of money. One of the first things players learn in Texas Hold’em is a list of two-card starting hands to play or fold, based on your table position and actions from players before you.* When Texas Hold’em first developed in the sixties, some expert players innovated deceptive plays with middle cards consecutive in rank and of the same suit (like the six and seven of diamonds). In poker shorthand, such cards are called “suited connectors.”

Suited connectors have the attraction of making a powerful, camouflaged straight or a flush. Expert players might choose to play these types of hands in a very limited set of circumstances, namely where they feel they could fold the hand at a small loss; successfully bluff if it doesn’t develop; or extract maximum value in later betting rounds by trapping a player with conventionally stronger starting cards when the hand does develop favorably.

Unfortunately, the mantra of “win big or lose small with suited connectors” filtered down over the years without the subtlety of the expertise needed to play them well or the narrow circumstances needed to make those hands profitable. When I taught poker seminars, most of my students strongly believed suited connectors were profitable starting cards under pretty much any circumstances. When I asked why, I would hear “everyone knows that” or “I see players cleaning up with suited connectors all the time on TV.” But no one I asked had kept a P&L on their experience with suited connectors. “Do that,” I’d say, “and report back what you find.” Lo and behold, players who came back to me discovered they were net losers with suited connectors.

Dietary advice offers a more consequential example. Duke points to research secretly funded by the sugar industry and to the growth of “reduced-fat” foods as reasons to examine how recommendations became established. She describes the historical food pyramid’s emphasis on carbohydrates and concern about fat. David Ludwig, a Harvard Medical School professor and doctor at Boston Children’s Hospital, criticized that shift in the Journal of the American Medical Association: “Contrary to prediction, total calorie intake increased substantially, the prevalence of obesity tripled, the incidence of type 2 diabetes increased many-fold, and the decades-long decrease in cardiovascular disease plateaued and may reverse, despite greater use of preventive drugs and surgical procedures.” These trends motivate questions about the advice, but do not by themselves establish a single cause of the changes in health.

Low-fat diets became the suited connectors of our eating habits.

Even though our default is “true,” if we were good at updating our beliefs based on new information, our haphazard belief-formation process might cause relatively few problems. Sadly, this is not the way it works. We form beliefs without vetting most of them, and maintain them even after receiving clear, corrective information. In 1994, Hollyn Johnson and Colleen Seifert reported in the Journal of Experimental Psychology the results of a series of experiments in which subjects read messages about a warehouse fire. For subjects reading messages mentioning that the fire started near a closet containing paint cans and pressurized gas cylinders, that information (predictably) encouraged them to infer a connection. When, five messages later, subjects received a correction that the closet was empty, they still answered questions about the fire by blaming burning paint for toxic fumes and citing negligence for keeping flammable objects nearby. (This shouldn’t be a surprise to anyone recognizing the futility of issuing a retraction after reporting a news story with a factual error.)

Truthseeking, the desire to know the truth regardless of whether the truth aligns with the beliefs we currently hold, is not naturally supported by the way we process information. We might think of ourselves as open-minded and capable of updating our beliefs based on new information, but these studies show ways that updating can fail. We may reinterpret new information to preserve an existing belief. Recognizing that tendency gives us something to check; it does not mean correction is impossible.