That’s the key to the experiment, for half the subjects were told that if the figure was a “farm animal,” they were to drink the juice and if it was a “sea creature,” they were to drink the smoothie; the other half were told the reverse. Then, after the subjects had viewed the image, the researchers asked them to identify the animal they’d seen. If the students’ motivations biased their perceptions, the unconscious minds of the subjects who were told that farm animal equals orange juice would bias them toward seeing a horse. Similarly, the unconscious minds of those told that farm animal equals disgusting smoothie would bias them toward seeing the seal. And that’s just what happened: among those hoping to see a farm animal, 67 percent reported seeing a horse, while among those hoping to see a sea creature, 73 percent identified a seal.
Dunning’s study was certainly persuasive about the impact of motivation on perception, but the ambiguity at hand was very clear and simple. Everyday life experiences, by contrast, present issues far more complex than deciding what animal you’re looking at. Talent at running a business or a military unit, the ability to get along with people, the desire to act ethically, and myriad other traits that define us are all complicated qualities. As a result, our unconscious can choose from an entire smorgasbord of interpretations to feed our conscious mind. In the end we feel we are chewing on the facts, though we’ve actually been chomping on a preferred conclusion.
Biased interpretations of ambiguous events are at the heart of some of our most heated arguments. In the 1950s, a pair of psychology professors, one from Princeton, the other from Dartmouth, decided to see if, even a year after the event, Princeton and Dartmouth students would be capable of objectivity about an important football game.22 The game in question was a brutal match in which Dartmouth played especially rough but Princeton came out on top. The scientists showed a group of students from each school a film of the match and asked them to take note of every infraction they spotted, specifying which were “flagrant” or “mild.” Princeton students saw the Dartmouth team commit more than twice as many infractions as their own team, while Dartmouth students counted about an equal number on both sides. Princeton viewers rated most of the Dartmouth fouls as flagrant but few of their own as such, whereas the Dartmouth viewers rated only a few of their own infractions as flagrant but half of Princeton’s. And when asked if Dartmouth was playing intentionally rough or dirty, the vast majority of the Princeton fans said “yes,” while the vast majority of the Dartmouth fans who had a definite opinion said “no.” The researchers wrote, “The same sensory experiences emanating from the football field, transmitted through the visual mechanism to the brain … gave rise to different experiences in different people…. There is no such ‘thing’ as a game existing ‘out there’ in its own right which people merely ‘observe.’”
I like that last quote because, though it was written about football, it seems to be true about the game of life in general. Even in my field, science, in which objectivity is worshipped, it is often clear that people’s views of the evidence are highly correlated to their vested interests. For example, in the 1950s and ’60s a debate raged about whether the universe had had a beginning or whether it had always been in existence. One camp supported the big bang theory, which said that the cosmos began in a manner indicated by the theory’s name. The other camp believed in the steady state theory, the idea that the universe had always been around, in more or less the same state that it is in today. In the end, to any disinterested party, the evidence landed squarely in support of the big bang theory, especially after 1964, when the afterglow of the big bang was serendipitously detected by a pair of satellite communications researchers at Bell Labs. That discovery made the front page of the New York Times, which proclaimed that the big bang had won out. What did the steady state researchers proclaim? After three years, one proponent finally accepted it with the words “The universe is in fact a botched job, but I suppose we shall have to make the best of it.” Thirty years later, another leading steady state theorist, by then old and silver-haired, still believed in a modified version of his theory.23
The little research that has been done by scientists on scientists shows that it isn’t uncommon for scientists to operate as advocates rather than impartial judges, especially in the social sciences, in which there is greater ambiguity than in the physical sciences. For example, in one study, advanced graduate students at the University of Chicago were asked to rate research reports dealing with issues on which they already had an opinion.24 Unbeknownst to the volunteers, the research reports were all phony. For each issue, half the volunteers saw a report presenting data that supported one side, while the other half saw a report in which the data supported the opposite camp. But it was only the numbers that differed—the research methodology and presentation were identical in both cases.
When asked, most subjects denied that their assessment of the research depended on whether the data supported their prior opinion. But they were wrong. The researcher’s analysis showed that they had indeed judged the studies that supported their beliefs to be more methodologically sound and clearly presented than the otherwise identical studies that opposed their beliefs—and the effect was stronger for those with strong prior beliefs.25 I’m not saying that claims of truth in science are a sham—they aren’t. History has repeatedly shown that the better theory eventually wins. That’s why the big bang triumphed and the steady state theory died, and no one even remembers cold fusion. But it is also true that scientists with an investment in an established theory sometimes stubbornly cling to their old beliefs. Sometimes, as the economist Paul Samuelson wrote, “science advances funeral by funeral.”26
Because motivated reasoning is unconscious, people’s claims that they are unaffected by bias or self-interest can be sincere, even as they make decisions that are in reality self-serving. For example, many physicians think they are immune to monetary influence, yet recent studies show that accepting industry hospitality and gifts has a significant subliminal effect on patient-care decisions.27 Similarly, studies have shown that research physicians with financial ties to pharmaceutical manufacturers are significantly more likely than independent reviewers to report findings that support the sponsor’s drugs and less likely to report unfavorable findings; that investment managers’ estimates of the probabilities of various events are significantly correlated to the perceived desirability of those events; that auditors’ judgments are affected by the incentives offered; and that, at least in Britain, half the population believes in heaven, but only about a quarter believes in hell.28
Recent brain-imaging studies are beginning to shed light on how our brains create these unconscious biases. They show that when assessing emotionally relevant data, our brains automatically include our wants and dreams and desires.29 Our internal computations, which we believe to be objective, are not really the computations that a detached computer would make but, rather, are implicitly colored by who we are and what we are after. In fact, the motivated reasoning we engage in when we have a personal stake in an issue proceeds via a different physical process within the brain than the cold, objective analysis we carry out when we don’t. In particular, motivated reasoning involves a network of brain regions that are not associated with “cold” reasoning, including the orbitofrontal cortex and the anterior cingulate cortex—parts of the limbic system—and the posterior cingulate cortex and precuneus, which are also activated when one makes emotionally laden moral judgments.30 That’s the physical mechanism for how our brains manage to deceive us. But what is the mental mechanism? What techniques of subliminal reasoning do we employ to support our preferred worldviews?