Saturday, June 28, 2008

A false belief about John McCain

We have encountered some resistance to the ideas in the Times editorial from readers who took issue with our focus on the Obama example. They felt that this was one-sided.

After some asking around, we now recall that there was a false belief about John McCain, dating to the 2000 Presidential primary campaign. He was doing well until the South Carolina primary, at which time rumors surfaced about a mixed-race child that he had allegedly fathered. Apparently, this did not play well with Southern voters. Shortly thereafter, his candidacy faltered.

On that note: ideas often have staying power if they evoke a strong emotional reaction. Here is a study suggesting that feelings of disgust make an idea memorable.

I hope the focus on one example doesn't deter readers from considering the ideas in the article carefully. This would be ironic, considering that a major point is that we tend to discount statements that contradict our worldview.

Thursday, June 26, 2008

The neuroscience behind Swift-boating

In Friday's New York Times, we have an editorial on the brain science of why people form false beliefs. It's timely because of the rash of rumors that have sprung up around Presidential candidate Barack Obama - for instance, the false idea that he is a Muslim.

The Times editorial format doesn't allow links to supporting literature. So we thought we'd provide the text here, complete with embedded links to key papers.

Update, Sunday 3:00pm: The story was most-emailed over the last 24 hours, for 2 days running. At this writing it's #5 most-emailed over the last 7 days.

Also, it's #2 most-blogged-about over the last 3 days. That's a close second to the story about the kids who all changed their middle name to Barack Obama's out of solidarity.

Your brain lies to you

False beliefs are everywhere. Eighteen percent of Americans think the sun revolves around the earth, one poll has found. Thus it seems slightly less egregious that, according to another poll, 10 percent of us think that Senator Barack Obama, a Christian, is instead a Muslim. The Obama campaign has created a Web site to dispel misinformation. But this effort may be more difficult than it seems, thanks to the quirky way in which our brains store memories — and mislead us along the way.

The brain does not simply gather and stockpile information as a computer’s hard drive does. Facts are stored first in the hippocampus, a structure deep in the brain about the size and shape of a fat man’s curled pinkie finger. But the information does not rest there. Every time we recall it, our brain writes it down again, and during this re-storage, it is also reprocessed. In time, the fact is gradually transferred to the cerebral cortex and is separated from the context in which it was originally learned. For example, you know that the capital of California is Sacramento, but you probably don’t remember how you learned it.

This phenomenon, known as source amnesia, can also lead people to forget whether a statement is true. Even when a lie is presented with a disclaimer, people often later remember it as true.

With time, this misremembering only gets worse. A false statement from a noncredible source that is at first not believed can gain credibility during the months it takes to reprocess memories from short-term hippocampal storage to longer-term cortical storage. As the source is forgotten, the message and its implications gain strength. This could explain why, during the 2004 presidential campaign, it took some weeks for the Swift Boat Veterans for Truth campaign against Senator John Kerry to have an effect on his standings in the polls. [Note: see Sam's meta-analysis of polls from 2004.]

Even if they do not understand the neuroscience behind source amnesia, campaign strategists can exploit it to spread misinformation. They know that if their message is initially memorable, its impression will persist long after it is debunked. In repeating a falsehood, someone may back it up with an opening line like “I think I read somewhere” or even with a reference to a specific source.

In one study, a group of Stanford students was exposed repeatedly to an unsubstantiated claim taken from a Web site that Coca-Cola is an effective paint thinner. Students who read the statement five times were nearly one-third more likely than those who read it only twice to attribute it to Consumer Reports (rather than The National Enquirer, their other choice), giving it a gloss of credibility.

Adding to this innate tendency to mold information we recall is the way our brains fit facts into established mental frameworks. We tend to remember news that accords with our worldview, and discount statements that contradict it.

In another Stanford study, 48 students, half of whom said they favored capital punishment and half of whom said they opposed it, were presented with two pieces of evidence, one supporting and one contradicting the claim that capital punishment deters crime. Both groups were more convinced by the evidence that supported their initial position.

Psychologists have suggested that legends propagate by striking an emotional chord. In the same way, ideas can spread by emotional selection, rather than by their factual merits, encouraging the persistence of falsehoods about Coke — or about a presidential candidate.

Journalists and campaign workers may think they are acting to counter misinformation by pointing out that it is false. But by repeating a false rumor, they may inadvertently make it stronger. In its concerted effort to “stop the smears,” the Obama campaign may want to keep this in mind. Rather than emphasize that he is not a Muslim, for instance, it may be more effective to stress his discovery of Christianity in his twenties.

Consumers of news, for their part, are prone to selectively accept and remember statements that reinforce beliefs they already hold. In a follow-up to the study of students’ impressions of evidence about the death penalty, researchers found that even when subjects were given a specific instruction to be objective, they were still inclined to reject evidence that disagreed with their beliefs.

In the same study, however, when subjects were asked to imagine their reaction if the evidence had pointed to the opposite conclusion, they were more open-minded to information that contradicted their beliefs. Apparently, it pays for consumers of controversial news to take a moment and consider that the opposite interpretation may be true.

In 1919, Justice Oliver Wendell Holmes of the Supreme Court wrote that “the best test of truth is the power of the thought to get itself accepted in the competition of the market.” Holmes erroneously assumed that ideas are more likely to spread if they are honest. Our brains do not naturally obey this admirable dictum, but by better understanding the mechanisms of memory perhaps we can move closer to Holmes’s ideal.

Monday, June 23, 2008

Big in Catalonia (with some loss in translation)

For speakers of Catalan, a Romance language spoken in Spain: here's a television interview (requires registration) with me on TV3, a major Catalonian station. The production values are excellent - I want the flashing neuron video in the background! I am overdubbed; the English is audible underneath.

At least one analogy didn't translate well. In the book we point out that the brain is more like a busy Chinese restaurant than a computer. People tend to talk about brains as if they were a sort of biological computer, with pink mushy "hardware" and life-experience-generated "software." But actions in computers occur according to an overall plan and in a logical order. The brain, on the other hand, is crowded and chaotic, and people are running around to no apparent purpose, but somehow everything gets done in the end. Computers mostly process information sequentially, while the brain handles multiple channels of information in parallel. Because biological systems developed through natural selection, they have layers of systems that arose for one purpose and then were adopted for another, even though they don’t work quite right.

Interviewer after interviewer asked us about this analogy in a friendly but puzzled manner. We finally figured out why in Barcelona, when we passed by a Chinese restaurant. It was deserted. Naturally, we had to regroup. In the next interview I said the brain was more like...a crowded tapas bar. The host smiled and everybody liked it. Whew!

If you prefer your interviews in English, here we are on National Public Radio and in person at Google. There are more interviews on our book's website,

Sunday, June 8, 2008

Building Better (?) Brains

I've been interviewed by SETI Radio. That's right, the Search for Extra-Terrestrial Intelligence. They do a science program called Are We Alone. Despite its name, the show covers all kinds of earth-bound subjects, including neuroscience. This episode's on neuroplasticity, and will be available Tuesday.

The host Seth Shostak and I had fun. We talked about neural prosthetics, a very lively area of research. He had questions about a recent paper describing a monkey that operated a robot arm through neural signals transmitted through a brain implant. This technology might someday be useful for humans with damage to their spinal cord, arms, or legs.

One interesting point: one monkey started treating the robot arm like its own, to the point of licking it. This illustrates how the brain can be fooled into extending its body image beyond the actual body. It's a case of your brain telling you a white lie in order to keep things running smoothly. Brain lies are a major theme of our book. This is an excellent example.

The rest of the program is focused on "brain gyms," a recent fad. We are very skeptical. We have found that the claims about the effectiveness of these games are not well supported by scientific studies, especially considering that the effect of physical exercise on brain function is much larger. Read what we had to say about it here. Then go out and get some real exercise!