In 1996, Lyle Brenner, Derek Koehler and Amos Tversky conducted a study involving students from San Jose State University and Stanford University. The researchers were interested in how people jump to conclusions based on limited information. Previous work by Tversky, Daniel Kahneman and other psychologists found that people are “radically insensitive to both the quantity and quality of information that gives rise to impressions and intuitions,” so the researchers knew, of course, that we humans don’t do a particularly good job of weighing the pros and cons. But to what degree? Just how bad are we at assessing all the facts?

To find out, Brenner and his team exposed the students to legal scenarios. In one, a plaintiff named Mr. Thompson visits a drug store for a routine union visit. The store manager informs him that according to the union contract with the drug store, plaintiffs cannot speak with the union employees on the floor. After a brief deliberation, the manager calls the police and Mr. Thompson is handcuffed for trespassing. Later the charges were dropped, but Mr. Thompson is suing the store for false arrest.

All participants got this background information. Then, they heard from one of the two sides’ lawyers; the lawyer for the union organizer framed the arrest as an attempt to intimidate, while the lawyer for the store argued that the conversation that took place in the store was disruptive. Another group of participants – essentially a mock jury - heard both sides.

The key part of the experiment was that the participants were fully aware of the setup; they knew that they were only hearing one side or the entire story. But this didn’t stop the subjects who heard one-sided evidence from being more confident and biased with their judgments than those who saw both sides. That is, even when people had all the underlying facts, they jumped to conclusions after hearing only one side of the story.

The good news is that Brenner, Koehler and Tversky found that simply prompting participants to consider the other side’s story reduced their bias - instructions to consider the missing information was a manipulation in a later study - but it certainly did not eliminate it. Their study shows us that people are not only willing to jump to conclusions after hearing only one side’s story, but that even when they have additional information at their disposal that would suggest a different conclusion, they are still surprisingly likely to do so. The scientists conclude on a somewhat pessimistic note: “People do not compensate sufficiently for missing information even when it is painfully obvious that the information available to them is incomplete.”

In Brenner’s study, participants were dealing with a limited universe of information - the facts of the case and of the two sides’ arguments. But in reality – especially in the Internet era - people have access to a limitless amount of information that they could consider. As a result, we rely on rules of thumb, or heuristics, to take in information and make decisions. These mental shortcuts are necessary because they lessen the cognitive load and help us organize the world – we would be overwhelmed if we were truly rational.

This is one of the reasons we humans love narratives; they summarize the important information in a form that’s familiar and easy to digest. It’s much easier to understand events in the world as instances of good versus evil, or any one of the seven story types. As Daniel Kahneman explains, “[we] build the best possible story form the information available… and if it is a good story, [we] believe it.” The implication here is that it’s how good the story is, not necessarily its accuracy, that’s important.

But narratives are also irrational because they sacrifice the whole story for one side of a story that conforms to one’s worldview. Relying on them often leads to inaccuracies and stereotypes. This is what the participants in Brenner’s study highlight; people who take in narratives are often blinded to the whole story - rarely do we ask: “What more would I need to know before I can have a more informed and complete opinion?”

The last several years have seen many popular psychology books that touch on this line of research. There’s Ori and Rom Brafman’s Sway, Dan Ariely’s Predictably Irrational and, naturally, Daniel Kahneman’s Thinking, Fast and Slow. If you could sum up the popular literature on cognitive biases and our so-called irrationalities it would go something like this: we only require a small amount of information, often times a single factoid, to confidently form conclusions and generate new narratives to take on new, seemingly objective, but almost entirely subjective and inaccurate, worldviews.

The shortcomings of our rationality have been thoroughly exposed to the lay audience. But there’s a peculiar inconsistency about this trend. People seem to absorb these books uncritically, ironically falling prey to some of the very biases they should be on the lookout for: incomplete information and seductive stories. That is, when people learn about how we irrationally jump to conclusions they form new opinions about how the brain works from the little information they recently acquired. They jump to conclusions about how the brain jumps to conclusions and fit their newfound knowledge into a larger story that romantically and naively describes personal enlightenment.

Tyler Cowen made a similar point in a TED lecture a few months ago. He explained it this way:

There’s the Nudge book, the Sway book, the Blink book… [they are] all about the ways in which we screw up. And there are so many ways, but what I find interesting is that none of these books identify what, to me, is the single, central, most important way we screw up, and that is, we tell ourselves too many stories, or we are too easily seduced by stories. And why don’t these books tell us that? It’s because the books themselves are all about stories. The more of these books you read, you’re learning about some of your biases, but you’re making some of your other biases essentially worse. So the books themselves are part of your cognitive bias.

The crux of the problem, as Cowen points out, is that it’s nearly impossible to understand irrationalities without taking advantage of them. And, paradoxically, we rely on stories to understand why they can be harmful.

To be sure, there’s an important difference between the bias that comes from hearing one side of an argument and (most) narratives. A corrective like “consider the other side” is unlikely to work for narratives because it’s not always clear what the opposite would even be. So it’s useful to avoid jumping to conclusions not only by questioning narratives (after all, just about everything is plausibly a narrative, so avoiding them can be pretty overwhelming), but by exposing yourself to multiple narratives and trying to integrate them as well as you can.

In the beginning of the recently released book The Righteous Mind, social psychologist Jonathan Haidt explains how some books (his included) make a case for how one certain thing (in Haidt’s case, morality) is the key to understanding everything. Haidt’s point is that you shouldn’t read his book and jump to overarching conclusions about human nature. Instead, he encourages readers to always think about integrating other points of view (e.g., morality is the most important thing to consider) with other perspectives. I think this is a good strategy for overcoming a narrow-minded view of human cognition.

It’s natural for us to reduce the complexity of our rationality into convenient bite-sized ideas. As the trader turned epistemologist Nassim Taleb says: “We humans, facing limits of knowledge, and things we do not observe, the unseen and the unknown, resolve the tension by squeezing life and the world into crisp commoditized ideas.” But readers of popular psychology books on rationality must recognize that there’s a lot they don’t know, and they must be beware of how seductive stories are. The popular literature on cognitive biases is enlightening, but let’s be irrational about irrationality; exposure to X is not knowledge and control of X. Reading about cognitive biases, after all, does not free anybody from their nasty epistemological pitfalls.

Moving forward, my suggestion is to remember the lesson from Brenner, Koehler and Tversky: they reduced conclusion jumping by getting people to consider the other information at their disposal. So let’s remember that the next book on rationality isn’t a tell-all - it’s merely another piece to the puzzle. This same approach could also help correct the problem of being too swayed by narratives – there are anyways multiple sides of a story.

Ultimately, we need to remember what philosophers get right. Listen and read carefully; logically analyze arguments; try to avoid jumping to conclusions; don’t rely on stories too much. The Greek playwright Euripides was right: Question everything, learn something, answer nothing.


The author personally thanks Dave Nussbaum for his helpful editorial comments and criticisms. Dave is a social psychologist who teaches at the University of Chicago. Follow him on Twitter and check out his homepage.

Image: by Wyglif on Wikimedia Commons.