Why We Make Mistakes Blog

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2010-03-31T13:14:00.001-07:00

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The Dirty Truth

2010-02-24T08:59:00.000-08:00

Question: Why do we keep making the same mistake over and over?

Answer: Because we fail to identify the root cause of the mistake to begin with -- a tendency researchers call, "misattribution."

Example: Washing your clothes. Say you get a stain on your shirt. You throw the shirt in the washing machine, add some detergent and 45 minutes later -- Voila! – the stain is still there.

You cuss. You holler. You kick the washing machine. Maybe you blame the detergent. But do you blame yourself? Nooooo. But maybe should.

According to a recent study in The Wall Street Journal, most Americans -- 53% -- don’t use the recommended amount of detergent per wash load. Instead they guess, usually filling the cap up to the top. This is a big mistake.

Why? Because detergent "overpouring" creates a high, foamy tide inside the machine, lifting soil and lint above the water level so it isn't rinsed away. That leaves residue on clothing that fades colors and attracts more dirt.

It’s also bad for your washing machine. Inside the machine, detergent buildup encourages odor and bacteria growth, and leads in time to wear and tear that will require professional attention.

So why do we do this? Because we don’t read the instructions. And why don’t we read the instructions? Because we think we know better. Most of us, the article reports, have done so many loads of laundry in our lives that we consider ourselves to be laundry experts. And experts don’t need no stinking instructions.

So there you have it: Ignorance and overconfidence all wrapped into one.

Class dismissed.

Foul? What foul?

2010-02-01T09:27:00.000-08:00

For another example of how deeply-ingrained biases can affect our judgment -- even when we try to be objective -- check out this recent study on fouls during soccer games. (And thanks to my old soccer teammate Robbie Woodward for sending it along.)

Researchers at Rotterdam School of Management, Erasmus University, researched all recorded fouls in three major soccer competitions over seven years. They discovered an ambiguous foul is more likely to be attributed to the taller of two players.

Similar studies of over the years have found that the judgment of referees can be biased by other factors, too -- such as the color of a hockey team's jersey (teams with black jerseys accrue more fouls) or even the racial makeup of officiating crew in the National Basketball Association.

But we go on pretending the biases don't exist.

DWD (Driving While Distracted)

2010-01-26T08:27:00.000-08:00

Readers of this blog have heard us carp for some time about the dangers of distracted driving. Now, the federal government is doing something to stop this nuttiness. Effective immediately, drivers of commercial trucks and buses will no longer be allowed to text while driving. Under federal guidelines that U.S. Transportation Department announced today, drivers of big rigs and buses may be subject to civil or criminal penalties of up to $2,750.

Now, if the feds would apply a similar rule to the rest of the drivers on the road, we'd all be much safer.

Hack Me

2010-01-22T09:36:00.000-08:00

Readers of Why We Make Mistakes already know why we pick computer passwords that are easily remembered -- and easily hacked (see pages 33-34). But if you have forgotten why or need more proof, check out the New York Times article on commonly-used passwords. Security researchers discovered a list of 32 million passwords that had been stolen from a website. And the number one password was...123456.(Number two was: 12345.)

Full-Body Scanners and Error Rates

2010-01-11T09:07:00.000-08:00

Ah, full-body scanners. They're supposed to make us safer. But will they?

My hunch is: not much. My guess is based not on the scanners themselves (which are intrusive and come with real risks, like additional radiation deaths), but on the people who do the scanning.

Undercover tests conducted at major airports show that the "miss rates" for baggage inspectors using conventional technology is between 60% and 75%. That's a lot.

Has the Transportation Security Administration (or anyone else) assured us that full-body scans will result in lower error rates? If so, I've seen no such assurance.

Ultimately, all scans must be interpreted by the people behind the scanners. And that's where the problem comes in. As work by researchers like Jeremy Wolfe has demonstrated, human beings have real-world limits on their ability to detect objects, especially ones that they rarely see, such as bombs and guns. That's why the current miss rate is so high -- and why it is unlikely to improve with full-body scanners.

Upwardly Mobile

2009-12-07T07:37:00.000-08:00

As readers of Why We Make Mistakes know, multi-tasking is usually a bad idea. It's an especially bad idea when you are behind the wheel of a car. Talking on a cell phone or texting while you are driving dramatically increases your chances of an accident. But we do it anyway because, among other reasons, we are overconfident about our abilities to multi-task.

For some interesting history about how we got to this point, see the page-one story by Matt Richtel in today's New York Times. As the article notes:

"Long before cellphones became common, industry pioneers were aware of the risks of multitasking behind the wheel. Their hunches have been validated by many scientific studies showing the dangers of talking while driving and, more recently, of texting.

"Despite the mounting evidence, the industry built itself into a $150 billion business in the United States largely by winning over a crucial customer: the driver."

Asleep at the Wheel -- Again

2009-10-23T11:09:00.000-07:00

We've written before about the problem of pilots falling asleep midflight.

Now, it seems that this has happened again.

Northwest Airlines Flight 188, en route to Minneapolis, overshot the airport -- way overshot the airport. The pilots didn't turn around until they were over Eau Claire, Wis., 150 miles away.

The pilots, who have not been identified, reportedly told the Federal Bureau of Investigation and the airport police that “they were in a heated discussion over airline policy and they lost situational awareness.”

Right.

The plane, an Airbus A320, which carried two pilots and three flight attendants as well as 144 passengers, was cruising at 37,000 feet when the crew stopped responding to air traffic controllers and airline dispatchers. According to the Wall Street Journal, the radio silence continued for 78 minutes.

According to the same article, "pilot fatigue has long been regarded as one of the most serious safety issues confronting commercial aviation."

The question is: When is the FAA going to wake up?

Information Overload

2009-10-21T13:41:00.000-07:00

More than 35 years ago, in a now-classic piece of research, Paul Slovic reported on the ability of handicappers to predict the outcome of horse races. At first, Slovic let the handicappers use any five pieces of information they wanted -- the jockey’s weight, for instance, or the horse’s previous race performance. Then he let them use 10 pieces of information. Then 20, and, finally, 40.

Slovic was studying the stress caused by information overload. What he found was fascinating: with more information, the accuracy of the predictions did not improve -- it was no better with 40 pieces of information than it was with 5.

But the confidence in those predictions did improve. This increased substantially, from less than 20% with 5 pieces of information to more than 30% with 40 pieces of information.

I thought about Slovic's findings as I read about the Galleon Group, the hedge fund whose rotund leader, Raj Rajaratnam, was arrested earlier this week on insider trading charges.

The pressure at Galleon was intense. According to published reports, analysts there were browbeaten to come up with new information on companies whose stock the fund was interested in.

But that information, at least in some cases, didn't seem to help -- and may even have hurt. As Alex Berenson reported in today's New York Times, Mr. Rajaratnam "lost millions of dollars from what prosecutors characterize as insider trading."

In one case alone, involving the chip maker Advanced Micro Devices, Galleon reportedly lost $30 million.

What is interesting here is not that some of Galleon's trades went bad; one would expect that. What is interesting is that Galleon apparently didn't learn what Slovic did: More information doesn't necessarily lead to better decisions. But it can lead to costly ones.

Results Not Typical

2009-10-06T10:04:00.000-07:00

In Why We Make Mistakes, I write about what some people call "bikini power." This is the power of weight-loss ads featuring women in bikinis to convince us that we, too, can look socko in a swimsuit -- even if the odds are against it.

I cite the case of NutriSystem, the diet company based in Horsham, Penn., whose ads frequently feature the bikini-clad. Its securities filings, though, give a different image of their customers: most are "serial dieters" who have repeatedly tried and failed to keep weight off. On average, they are female, 44 years old, and weigh 210 pounds. Most start out wanting to lose 60 pounds but end up losing only about 20. Typically, after 10 or 11 weeks, they give up and drop out of the company's program.

For decades, the Federal Trade Commission has allowed diet companies to use ads like NutriSystem's so long as the ads feature a tiny, three-word disclaimer: "Results not typical."

Well, that is about to change. New FTC guidelines, last revised in 1980, require weight-loss companies and others to state just how "not typical" their results are.

Under the revised guidelines, advertisements that feature a consumer and convey the consumer's experience with a product or service as typical when that is not the case will be required to clearly disclose the results that consumers can generally expect.

In contrast to the 1980 version of the guidelines – which allowed advertisers to describe unusual results in a testimonial as long as they included a disclaimer such as “results not typical” – the revised guides no longer contain this safe harbor.

But the guidelines, so far as I can tell, say nothing about banning the use of bikinis....

Buy High, Sell Low

2009-09-19T08:14:00.001-07:00

If you want a good example of how overconfidence leads to mistakes (and very expensive ones at that), check out Floyd Norris's column in today's New York Times. Usually, we see overconfidence at work in individual errors; here, we see it at work on the corporate level.

Norris's column focuses on the allure created when publicly traded companies buy back their own stock (parenthetical comments below are my own):

"One reason investors have viewed buybacks as a positive was that they indicated corporate management and boards were confident (there's that word!) that their share prices were low and that the company would not need the cash for a possible downturn in business.

"Unfortunately," Norris concludes, "there is little evidence that is the case."

Records show that companies typically buy their own stock at the top of the market -- a colossal waste of money. He cites the case of American International Group. In 2007 it spent $6 billion buying back its own stock. In the first quarter of 2008, it spent another $1 billion. And then? Ka-boom. The bottom fell out of the market. Today, AIG would be broke without a massive federal bailout.

And AIG is no exception. Home Depot did the same thing. In the third quarter of 2007, Norris reports, it bought $10 billion of its own stock at an average price of $37 a share. By early this year, the price had fallen to $18. You talk about do-it-yourself investing!

Yessir, Home Depot: You can do it. We can help. Next time, just hang onto the cash.

Swiss Cheese and Medical Errors

2009-09-08T10:13:00.000-07:00

There's no real reason to single out medical errors from all the other types of errors in the world, except for one: they kill a lot of people. According to a leading study on the matter, about 98,000 patients in the U.S. die each year from medical mistakes.

This doesn't cause much of a public outcry, though, because most medical mistakes are buried with the patient. On the rare occasion when an error is revealed, blame is usually attached to an individual doctor or nurse (or both).

But if you want to understand why this approach to blaming individuals doesn't stop future errors from happening over and over again, read Josie's Story, which is reviewed here. The book is written by Sorrel King, whose 18-month old daughter, Josie, died from complications from treatment in 2001 at the world-famous Johns Hopkins Medical Center.

From the review:

"As Ms. King notes, the problem is often not a single doctor or nurse or misplaced decimal point on a medication vial but rather faulty systems and communication breakdowns."

Exactly. Most mistakes can be best understood by what experts on human error call the "Swiss cheese effect." Basically, errors are like the holes in slices Swiss cheese; for an error to happen, all the holes in various slices of the cheese have to line up. When they do, an error gets through.

Anyone truly interested in reducing errors in any workplace -- whether it's an operating room or a factory floor -- should take note.

D.W.T.

2009-08-26T13:18:00.001-07:00

One of the most common sources of human error is multi-tasking, especially when performed behind the wheel of a car.

D.W.T. or Driving While Texting, is a supremely bad idea; it's been implicated in the crash of a train in Los Angeles and a trolley in Boston.

It is also becoming illegal. In Utah, for instance, texting and emailing while driving are now punishable by a $750 fine and 90 days in jail.

The state has put out a video, which you can see here. There's also a similar, though very graphic, video appearing now in the U.K.

As the Wall Street Journal points out, companies are scrambling to come up with new texting-safety apps that block texts or minimize the distraction they cause.

But you don't need any of these; you could just hang up the phone and drive.

The Same Mistake, Again and Again

2009-08-18T11:58:00.000-07:00

We've talked before about why we so often seem to make the same mistake again and again. Now comes another factor: stress.

In a recent study in the journal Science, Nuno Sousa and his colleagues describe what happens to chronically stressed rates.

As Natalie Angier of the New York Times put it, "the rodents were cognitively predisposed to keep doing the same things over and over, to run laps in the same dead-end rat race..."

Sound familiar?

Why It's Dumb to Text and Drive

2009-07-27T16:20:00.000-07:00

We've written before about the folly of texting. (See our May 26 blog here.) Now comes even more proof. A new study by the Virginia Tech Transportation Institute finds that texting while driving doesn't merely double or triple the risk of a crash; it increases the risk 23 times.

Compared with other sources of driver distraction, “texting is in its own universe of risk,” said Rich Hanowski, who oversaw the study at the institute, which is affiliated with Virginia Tech.

For The Non-Believers Among Us

2009-07-18T11:57:00.001-07:00

Readers of this blog know that we've been harping for some time on the perils of multi-tasking, especially multi-tasking behind the wheel. If you still think you can text and drive at the same time, maybe this piece in the New York Times will make you think otherwise. There's also an interesting follow-up, which you can find here.

Of Course We Gave Them a Good Rating...

2009-07-15T09:25:00.000-07:00

The nation's biggest public pension fund has now filed suit in California over $1 billion in losses it claims were caused by "wildly inaccurate" credit ratings.

The California pension fund, known as Calpers, says that highly complicated structured investment products that had been given a AAA rating are now worthless.

Calpers contends that in giving these securities their highest credit rating, the three top ratings agencies -- Moody's Investors Service, Standard & Poor's and Fitch -- "made negligent misrepresentation" to the fund.

Moreover, Calpers, in its suit, cites conflicts of interest by the agencies that rated these securities. Not only were they paid by the companies issuing the securities, it says; but they went one step further: All three agencies received lucrative fees for helping to structure the deals -- and then issued ratings on the deals they helped create.

Nice work if you can get it, right?

We'll see what the agencies have to say for themselves (the New York Times said that they either did not respond to request for comment or said they could not comment).

But in the meantime, the folks at Calpers -- and the credit rating agencies -- should bone up on how conflicts, even small ones, bias the judgment of people we rely on for financial advice. To do that, read one of George Loewenstein's papers here.

The Importance of Being Tall

2009-07-13T09:16:00.000-07:00

Here's another of life's fun facts that you can't do anything about: Tall people make more money.

The latest study, in Australia, found that being 6-feet tall raises annual income nearly $1,000 compared to men two inches shorter.

Why?

"Taller people are perceived to be more intelligent and powerful," according to the study, published recently in the Economic Record.

If that is so, then chalk it up to another of implicit associations we make in life. Associations are basically mental shortcuts, (or prejudices, if you like)that help us hack through life's jungle of information. For instance, if we are told a wine is from North Dakota (instead of California) we turn up our noses. If a pain pill is red or black (colors we associate with power) we rate it as being more effective than one colored white.

And now we learn that if someone is tall, we apparently associate their height with brains and brawn.

"Our estimates suggest that if the average man of about 178 centimeters [5 feet 10 inches] gains an additional five centimeters [2 inches] in height, he would be able to earn an extra $950 per year - which is approximately equal to the wage gain from one extra year of labor market experience," said study co-author Andrew Leigh, an economist at the Australian National University.

Associations, of course, can lead us into all sorts of erroneous judgments. A white pain, for instance, pill can be just as effective as a black one. And a tall man can be as dumb as a short one. (Though I must admit, I've never had a good wine from North Dakota.)

But before the tallest among you (at least the tallest Americans among you) start counting your blessings, consider this: For more than two centuries, until World War II, Americans had been the tallest people in the world. But in the 1950s, Americans' heights stabilized. In most of Europe, though, heights have rapidly increased.

What McNamara Learned

2009-07-07T11:11:00.001-07:00

Anyone interested in the study of human error can benefit from reading the powerfully written obituary of Robert McNamara that appears in today’s New York Times.

McNamara was a former secretary of defense and the primary architect of the Vietnam War. President Kennedy once called him the smartest man he ever met. Yet McNamara came to consider the Vietnam War as a colossal mistake – confessing in a 1995 memoir that it was “wrong, terribly wrong.”

It’s instructive to compare McNamara’s view of the Vietnam War with George Bush’s view of the war in Iraq.

The roots of both wars share a striking similarity: an overconfidence in the precision of intelligence. In the case of Vietnam, Congress authorized war after President Johnson contended that American warships had been attacked by North Vietnamese patrol boats in the Gulf of Tonkin in 1964. But, as a 2005 report by National Security Agency showed, the attacked never happened. Instead, American ships had been firing at radar shadows on a dark night. At the time, however, the agency’s experts in signals intelligence told McNamara that the evidence of the attack was iron-clad.

That phrase bears an eerie similarity to a more recent expression of war-time certainty. Remember when George Bush asked then-CIA director George Tenet how confident he was that Saddam Hussein possessed weapons of mass destruction?

“Don’t worry,” Tenet reportedly replied. “It’s a slam-dunk.”

Slam-dunk. Iron-clad. In both case men were certain, and in both cases men were wrong. What’s informative is how McNamara and Bush responded to being wrong. McNamara spent the rest of his life analyzing (and agonizing over) where and why he erred. Bush hasn’t.

McNamara’s conclusions were distilled in Errol Morris’s 2003 documentary, “The Fog of War: Eleven Lessons from the Life of Robert S. McNamara.” The greatest of those lessons, McNamara said, was to know one’s enemy. “We must try to put ourselves inside their skin and look at us through their eyes,” he said.

When McNamara did that, he explained in an oral history, he concluded that we failed to grasp the nature of the threat of communism. “What went wrong was a basic misunderstanding or misevaluation of the threat to our security represented by the North Vietnamese,” he said. “I am certain we exaggerated the threat.”

That line caught my eye because just last week, the Times ran a story saying, essentially, that we had repeated that error in Iraq. In a series of interrogations before his execution, Saddam Hussein told an F.B.I. agent that on the eve of the 2003 American invasion, Iraq was trapped between United Nations orders to demonstrate that it had disarmed and a fear that appearing too weak would invite attack from its powerful neighbor and foe, Iran.

In fact, Saddam so feared Iran that he told the F.B.I. that if United Nations sanctions against his country had been lifted, Iraq would have sought a security agreement with the United States to protect it from Iran. (Italics mine.)

“We did not appreciate how large the threat of Iran loomed in his thinking,” said Charles A. Duelfer, a veteran intelligence official who led the hunt for unconventional weapons in Iraq in 2004. He called the United States’ understanding of Iraq in 2003 “cartoonish.”

The interviews, noted the article, “underscore once again both Mr. Hussein’s striking miscalculation of the risks he faced and the United States’ mistaken estimate of the threat Iraq really posed.”

In his oral history at Berkeley, McNamara predicted as much. “We didn’t understand the Chinese; we didn’t understand the Vietnamese, particularly the North Vietnamese. So the first lesson is to know you opponents.

“I want to suggest to you that we don’t know our potential opponents today.”

One man learned from history; the other has not.

The gift that keeps on taking....

2009-06-30T09:51:00.001-07:00

We've written before about why gift cards are a big mistake (See our Jan. 6 post). Now comes even more evidence.

Today's Wall Street Journal reports that state governments are trying to grab those gift cards that are lying unused in your wallet, dresser drawer or purse.

Why? Big money, of course. Each year, Americans spend about $65 billion on gift cards -- but don't redeem $6.8 billion. In the past, that's meant free money for the big retailers that issue these cards. Home Depot Inc., for instance, reported $37 million in revenue from unredeemed gift cards in 2009. And last year, American Eagle Outfitters Inc. collected more than $12 million.

Now, cash-strapped states want in on the action. They want to consider unredeemed gift cards as "abandoned property" -- like that old safe-deposit box that Uncle Elmer had forgotten about. And, as abandoned property, the gift cards are no longer yours. Which is just one more reason gift cards are a bad idea.

Why we nod off on Fridays

2009-06-22T11:20:00.000-07:00

Notice anything odd about the jury verdict below?

"We, the Jury, find the Defendant Guilty of the offense of POSSESSION OF CRACK COCAINE.
"We, the jury, further find that the amount of crack cocaine WAS in the amount exceeding ten one hundred (100) grams as charged in the indictment."

Neither, apparently, did the jurors. But the defendant did. And if you read closely, you'll notice what he noticed: that the word "ten" in the second sentence is extraneous.

It may seem like a small error, but it was big enough that an Ohio appeals court ruled the defendant's prison sentence should be cut to just one year instead of 10.

The case nicely illustrates how easily we overlook things, relying instead on context to guide our understanding of what we read or see.

"Overlooking" mistakes are so common that researchers have given them their own designation: they are called “proofreader’s errors.” These humdrum errors reveal some interesting quirks about the way human perception works. One is that perception is economical; we notice some things and not others. And what we notice, to a degree, depends on who or what we are. If you're a dentist, you probably notice someone's teeth; if you're a manicurist, you notice hands.

In any event, our attention is not always equally distributed. When reading, for instance, we tend to pay a lot of attention to the beginnings words -- an area that we expect to be rich in cues about what may follow -- and less attention later on. Investors, interestingly, appear to do the same thing: they pay more attention to financial news released at the beginning of a week, but tend to nod off on Fridays.

No See 'Ums

2009-06-16T09:59:00.000-07:00

A new report by the World Health Organization says that traffic accidents worldwide kill an estimated 1.27 million people a year -- and that nearly half of these are pedestrians, cyclists and motorcyclists.

There's a good explanation for this: drivers often don't see them. That's because it is possible to look right at something and still not see all there is to see. This type of accident is so common, in fact, that traffic researchers have a phrase for it: a "looked-but-didn't-see" accident.

For a fantastic illustration of this phenomenon, check out a series of ads by Transport for London. It is using the ads to help make drivers aware of just how hard it can be to see things (like bicyclists) that you aren't looking for. Go ahead and take the test in the ads and see how well you do.

For more information on the phenomeneon, check out the visual cognition lab of Professor Dan Simons. It's great.

The Heart of the Matter

2009-06-15T10:59:00.000-07:00

A new study from Britain shows that more than half of the people surveyed could not accurately locate on a diagram the position of the human heart.

The study, published in the journal BMC Family Practice, showed there has been little improvement in anatomical knowledge since a similar study was performed in the 1970s.

This should come as no surprise, at least to readers of this blog. Overconfidence is a prime (though often well-camouflaged) culprit behind many of our mistakes. We often overestimate the precision of what we (and others) know. And this overestimation can lead to problems, especially when it comes to our health. One study conducted in the U.S. in 2007, for instance, found that doctors overestimate patient literacy, and that the lack of patient knowledge leads to poorer care.

Who -- me, biased? For a lousy $3 million?

2009-06-08T09:44:00.000-07:00

In a closely watched case that illuminates a common (and powerful) bias in human decision-making, the U.S. Supreme Court ruled today that the Constitution can require a state court judge to step aside when he is faced with a case involving a major campaign donor.

The case involves Brent D. Benjamin, now the chief justice of West Virginia's Supreme Court, and the Massey Energy Co., his major campaign contributor.

West Virginia, like most states, allows judges to be elected (instead of being appointed). And Massey's chairman, Don Blankenship, had spent $3 million in the 2004 election attacking an incumbent for the court. The incumbent lost and Benjamin won, which turned out to be a good thing for Massey: Benjamin twice joined 3-2 majorities to throw out a $50 million verdict against Massey, which was involved in a long-running dispute with another coal company.

Writing for the majority of the U.S. Supreme Court, Justice Anthony M. Kennedy noted that no “quid pro quo”had been established between Mr. Blankenship’s campaign contributions (which dwarfed those of other donors in the judicial elections), and Justice Benjamin’s stance in the lawsuit. But there was, he noted, “a serious, objective risk of actual bias.”

This squares with a raft of recent research on bias and gift-giving. As we've pointed out before, even a small gift like a coffee mug can bias the judgment of the person who receives it. The same is obviously true for a $3 million campaign contribution. No explicit quid-pro-quos are necessary; that's because the bias is implicit -- and inherent.

In fact, when judging the conduct of others it can be incredibly hard to be impartial -- even when we are trained to be unbiased. For an illustration of just how hard, see Justin Wolfers's eye-opening look (with Joseph Price) at biased officiating by NBA referees.

The Folly of Texting

2009-05-26T14:16:00.000-07:00

There have been a number of stories in the press lately on the follies of texting while doing almost anything else. One of the more recent involved a Boston trolley crash that injured 20 people. The 24-year-old trolley operator acknowledged he was texting his girlfriend at the time of the crash.

Now comes a story in today's New York Times. It reports that American teenagers sent and received an average if 2,272 text messages per month in the fourth quarter of 2008. This worries psychologists and physicians, who say obsessive texting is leading to anxiety, distraction in school and sleep deprivation. All of which is a grand way to make more errors.