The Rationality Project: One Man's Quest to Ignore His Gut Instinct

My brain is deeply flawed. And no offense, but so is yours.

Your brain is not rational. It's packed with dozens of misleading biases. It's home to an alarming number of false assumptions and warped memories. It processes data all wrong and makes terrible decisions. Problem is, the brain didn't come to us fully formed from a lab at MIT. The brain is merely an ad hoc collection of half-assed solutions that have built up over millions of years of evolution. It's Scotch tape and bubble gum. If it were a car, it would not be a Porsche; it'd be a 1976 Dodge Dart with faulty brakes and a missing headlight.

As one scientist puts it, we've got Stone Age minds living in silicon-age bodies. Our brains were formed to deal with Paleolithic problems. When my brain gets scared, it causes a spike in adrenaline, which might have been helpful when facing a mastodon, but it's highly counterproductive when facing a snippy salesman at the Verizon outlet.

And yet we remain enamored of our ancient responses. These last few years have been a golden age for our most primal impulses. We've got a president who's spent eight years leading from his gut, and look where that's got us. We've got Malcolm Gladwell's Blink, a best seller with a subtle thesis that has unfortunately been boiled down to the pro-intuition message "Don't think, blink." It's given birth to a million stupid decisions.

I've had enough. I'm going to try to revamp my brain. Bring it into the modern era. I'm going to root out all the irrational biases and Darwinian anachronisms and retrain my brain to be a perfectly rational machine. I will be the most logical man alive, unswayed by unconscious impulses. I'll use any means necessary--vigilance, repression, science. I'll also use duct tape, forty tubes of toothpaste, and a shroud over my cereal bowl. But I'm getting ahead of myself.

The Lake Wobegon Effect

I came up with Project Rationality a couple months ago. I'd always considered myself pretty logical, more Spock than Homer, more ego than id. But then I read a new book called Nudge, by Richard Thaler and Cass Sunstein, which details the alarming number of built-in irrational quirks of the brain. Then I read another recent book called Predictably Irrational. Then another. And another. Turns out brain-bashing is an exploding genre, right up there with tomes about inspirational dogs and atheism.

If you read these books all in a row, you will feel like amputating your head. You learn your brain is programmed to be bigoted and confirm stereotypes. It's easily fooled by anecdotal evidence. Or a pretty face. Or a guy in a uniform. It's a master of rationalization. It believes what it hears. It overreacts. It's hopelessly incompetent at distinguishing fact from fiction. There are scores of "cognitive biases" identified by researchers (Wikipedia lists more than a hundred of them).

When I told my brother-in-law Eric, a behavioral economist at Columbia, about my plan to eliminate all cognitive errors from my brain, he chuckled. He said I was suffering from the Lake Wobegon Effect: Our brains are delusively cocky. We all think we're better-looking, smarter, and more virtuous than we are. (It's named for Garrison Keillor's town, where "all the children are above average.")

"You're vastly overestimating your abilities."

The Availability Fallacy

I wake up on the first morning of Project Rationality this summer and find my wife, Julie, reading The New York Times. That's trouble. Journalism is an enemy of rationality.

What makes news? The unusual and the spectacular, which by their nature distort reality and pervert our decisions. You read headlines like 15 KILLED IN PLANE CRASH IN WYOMING. You don't read headlines like ANOTHER 2,000 DIED OF HEART DISEASE YESTERDAY. This leads to the Availability Fallacy. Our lazy mind gloms on to the most vivid, emotional examples. When we think of danger, we think of hideous plane crashes or acts of terrorism. Even though boring old cars kill eighty-four times more people.

Today, there's an article about salmonella. Eight hundred people have gotten sick from salmonella, possibly from tainted tomatoes--which later will turn out not to be the case. I'm a paranoid bastard, so I would normally purge our house of anything tomato-related: the pint of cherry tomatoes, the ketchup bottles, the Esquire cover of Andy Warhol in tomato soup. Salmonella would climb onto my list of Top Ten Worries.

Instead, I take my first countermeasures. I ask my wife for the newspaper, find a Sharpie, and scribble under the headline: "Meanwhile, millions of people ate tomatoes and did NOT get sick. But thousands did die from obesity."

"That's better," I tell my wife, handing it back to her. There's something validating about writing it out. I explain that every newspaper article should come with a reality-check box, like cigarettes and their Surgeon General's warnings. For now, I'll have to provide my own.

I go to the fridge and consider eating a cherry tomato to spite the media. But that'd be falling for the Reactance Bias, the unreasonable desire to do what others forbid you from doing.

Unit Bias

I do want to have breakfast, though. How to eat rationally? This will be tricky.

Well, one way is to eat less.

As humans, I've learned, we have an irrational urge to finish everything on our plates. No doubt this served our Paleolithic forefathers well when food was scarce and unreliable. But now it just makes us a bunch of fat-asses.

I recently read about this brilliant experiment at the University of Illinois a few years ago. They gave a group of test subjects bowls of soup. What they didn't tell them was this: Hidden tubes underneath the table were constantly refilling the bowls. Guess what? The subjects just kept on eating, long past when they were full. If the scientists hadn't dragged them from the table, they might have exploded.

I pour my MultiGrain Cheerios into a bowl, then cover the bowl with a napkin. I'm not going to let my brain see what's inside the bowl. That'd be too tempting. I'll just eat till I feel full. It's a time-consuming process trying to negotiate the spoon around the napkin. Which is probably a good thing, since it's healthier to eat slowly.

And yet I feel I have miles to go before I can say I ate a rational meal. Like yours, my brain is packed with food-related biases. People often choose the medium size at a restaurant even if the small would suffice--we have a fear of the extremes, so we go with the middle option. We find it logical to eat cows but not other mammals like dogs or mice. Studies have shown we find things tastier if we pay more for them. Or if we eat them out of fancier containers. Later in the day, I eat microwaved chili off our wedding plates. It's delicious.

Source Amnesia

Here's one thing I'm learning: My brain is full of shit. I need a mental colonic.

It's the end of Day One, and I'm grappling with the startling number of myths, half-truths, and outright lies that clog my brain. It's not that I believe in ghosts. Or creationism. Or "energy independence." My misconceptions are less obvious but just as false.

Consider brushing my hair. It sounds reasonable, and I suppose, for the first few seconds I get my hair into place, it is.

Problem is, I keep on brushing for another thirty seconds. I brush my hair till my scalp tingles. Why? Because someone--I think my mother--told me when I was about ten years old that you need to stimulate the scalp or you'll go bald. So that's what I've been doing for the last thirty years.

As soon as I uncover the almost-unconscious belief, it smells rotten, and about three minutes of Googling confirms it: It's a myth, about as effective as rubbing chicken manure on my head, another ancient remedy.

I call my mom to ask whether she was, in fact, the one who told me.

"That sounds like something I said," she says.

"Well, it's not true. It's a myth."

There's a pause. "Sorry."

"Well, I spent a lot of time brushing my hair because of that." (More than three total days of hair-brushing, to be precise.)

"I'm not sure what to tell you except sorry."

Damn. Now I'm the bad guy in this scenario.

"Anyway," she says. "Why were you taking advice from me about baldness? You should have talked to your dad."

"I was ten!"

I'm the victim of two brain flaws. First, we place too much trust in authority. We follow the captain even if it's clear he's leading us right over Havasu Falls. It's hardwired into our brains. The second is just as insidious: Source Amnesia. We forget where we learned a fact. Facts are initially stored in a pinkie-shaped region called the hippocampus. But eventually the information shifts over to the cerebral cortex--where, as Welcome to Your Brain authors Sam Wang and Sandra Aamodt put it, it is "separated from the context in which it was originally learned. For example, you know the capital of California is Sacramento, but you probably don't remember how you learned it." A fact learned in The Wall Street Journal gains as much credulity as a "fact" learned from your cousin's barber.

And it gets worse. Even if we are told--clearly warned--that something is false or unsubstantiated, we often remember it later as gospel.

I need to root out these untruths. With a little research, I refute some of my more dubious beliefs: Shaving your hair does not make it grow back thicker, turning lights on and off does not waste more energy, sugar does not make you hyperactive. Despite what Mom said, I don't need to wear socks or slippers around the house for health reasons; you can't get a cold from cold feet.

Yet when I try to go shoeless around the house, it causes me such low-grade angst, I give up and put my Merrells back on. They are stuck deep, these myths. And I know there are dozens, hundreds of other undiscovered falsehoods lurking in my neurons and warping my choices. But how do I identify them?

The Halo Effect

It's Day Three and I'm pissed at the brain. It's not just flawed; it's superficial and cruel, like a cable-TV pundit. This sunk in today when I was at Starbucks.

I bought a cappuccino and got back $1.35 in change. How much should I tip? Thirty-five cents or a dollar? I stuffed the dollar into the box and smiled at the barista.

As I poured my sugar, I realized I'd fallen for the Halo Effect. Terrible. One of the most evil biases I've run across. If a person is physically attractive, we unconsciously heap all sorts of wonderful, unrelated qualities onto them. Studies have shown we think attractive people are smarter than ugly people. We tend to hire them more often and promote them faster. We think they're more virtuous. Teachers treat attractive children better than their unfortunate-looking peers. In short, we judge a book by its cover.

And yes, the barista was really cute. A Maggie Gyllenhaal type with a moderate smattering of piercings. I know that was the reason I tipped her the buck. If she'd looked like Vladimir Putin, I would have gone with the thirty-five cents.

I unconsciously assumed she was a good person and deserved a dollar. I also, no doubt, unconsciously wanted to sleep with her and spread my DNA. (And assumed the sixty-five cents would help with that cause, naturally.)

The Halo Effect runs deep in our genes. It probably made sense to our hunter-gatherer ancestors. If someone had a misshapen face, there could be a greater chance he had an inherited disease. So you might want to avoid breeding with him. You want your offspring to have Grade-A genes.

I hate the Halo Effect. It's like Nature said, Hey, let's make life as unfair as possible. Let's load up the misery on one side and give all the happiness to the pretty people.

I call Richard Thaler, one of the coauthors of Nudge. (He's agreed to be my Rationality Guru.) "If you think about it," he says, "it's more rational to give the ugly one a bigger tip. Some investment banker is going to propose to the pretty one soon and she won't be working at Starbucks."

The next day, before going to lunch with my wife at a local café, I take countermeasures. I put duct tape on the top half of each lens of my glasses. I'm blind from the horizon up. This way, I figure, I can still function, but I won't be able to see the waitress's face. I won't be swayed by her hotness. My wife reminds me I'm lucky to be married to her.

My plan works--for a bit. I can't see our waitress's face. But I spend a lot of time listening to her voice--a bit husky, breathy--to try to discern her hotness. Then I leave a big tip because I feel like a dick for never making eye contact.

I call Thaler for a debriefing. "That was a good example of what you don't want to do," he says. "You could have been hit by a truck, first of all. Here's my advice: Sit in the café, drink your coffee, stare at the barista, then give your dollar to the ugly one."

Confirmation Bias

For someone who once deemed himself relatively rational, I have an astounding number of superstitions. I suppose "obsessive-compulsive rituals" sounds a bit better than "superstitions." Whatever they are, I've got so many, I can't count them all.

After turning off the faucet, I touch it twice.

I never start or end a conversation with the word you.

Whenever I swallow, I must swallow in pairs.

And on and on. They take up a lot of mental bandwidth.

Superstitions, I learn, stem from the Confirmation Bias. The faulty reasoning goes like this:

I've swallowed in pairs for fifteen years, and I'm alive and relatively okay.

If I stop swallowing in pairs, who knows what will happen? So I'll keep on swallowing in pairs.

Highly irrational. Today, I've vowed to snap the superstition chains. I will have a superstition-free day. Perhaps even life.

I fetch my son, plop down on the couch, and start reading him a story about a dangerously irresponsible zookeeper. Out of habit, I swallow--the first big test. I suppress the urge to swallow again. A solo swallow, for the first time in two decades.

It feels odd. Where's the closure? Man, I want to swallow again. I feel like I sang "Happy birthday to--" and just stopped mid-sentence. I mentally tuck away the fact that I've swallowed a single time, so that when this experiment is over, I can swallow a second time to even things out. Not good.

A few minutes later, I walk by the hall mirror. When I glance at my reflection, I start to contort my face into a yawnlike position, my lips obscuring my teeth. This yawning superstition started because I'm insecure about my overbite, so I hide it. It makes me resemble a baboon in estrus. I stop myself, relax my face. I'd forgotten about this quirk when I was making my list. These rituals are lurking everywhere.

The ritual-breaking has made me anxious. My heart rate has jumped. I'm hyperaware of everything going on, looking for any sign of catastrophe or disease.

"Everything okay?" I ask Julie.

"Uh, fine, thanks."

"Nothing bad has happened to you this morning?"

She shakes her head.

A couple hours later, I catch the digital clock in our bedroom change from minute 13 to 14. So what? I don't need to stop and stare at the clock until it changes from 14 to 15 so that the 13 is washed out of my mind.

By the end of the day, I'm on a high. Why didn't I do this fifteen, twenty years ago? Think of the time I could have saved.

I wake up the next morning, ready for another day of freedom. An hour into the day, I spill coffee all over my MacBook keyboard. Yeah, well, it happens. A few minutes later, Julie asks me if I've seen her earring. She's lost it somewhere. She looks upset--even more than lost-earring upset. Well, she says, a client of hers had just called and shouted some unreasonable demands. "She's a bulldozer," she says.

Then I get an angry e-mail about an essay I wrote. I'd made a big mistake--I hadn't made it clear that I disguised the identities of everyone in the essay--and it made me look like an insensitive ass-face.

I knew this would happen. What kind of an idiot am I to tempt fate? This experiment is over.

The Mere Exposure Effect

Maybe I've overreacted a bit. I'm sticking with my swallowing in pairs, but maybe there's other irrational behavior I can fix. I start analyzing every tiny decision again. Like my toothpaste preference.

I've brushed with Crest pretty much every day for the past thirty years. (The exception: One night last year, I brushed my teeth with Preparation H. The reasons were several: a poorly lit hotel bathroom, lack of sleep, a couple of Coronas, and two identically sized tubes in my Dopp kit.)

Why Crest? I can't say for sure. No pro/con list was ever drawn up. Some friend of mine at Camp Powhatan in Maine used Crest. He was cool and had seemingly good dental hygiene. I started using Crest--and never stopped.

It's scary once you start to scrutinize it. Probably 90 percent of our life decisions are powered by the twin engines of inertia and laziness.

Psychologists call it the Mere Exposure Effect. The basic idea is, I like Crest because I'm accustomed to Crest.

That's not good enough. I need a fully rational toothpaste. I need, first, to expand my dental-hygiene horizons. I go to the drugstore and buy a sample platter of forty tubes of toothpaste. (The cashier doesn't even bat an eye; I guess when people are buying bungee cords and vats of K-Y Jelly, this isn't a big deal.)

I go home and spend eighty minutes brushing. Pepsodent Smooth Mint. Colgate Luminous Crystal Clean Mint. Aquafresh Extreme Clean Whitening Mint Experience. I never realized how much I hate mint. What a tongue-stinging, foul taste. It brings back bad memories of the green goo that goes with lamb chops. What kind of hold do the mint growers have on toothpaste makers? Bite me, mint lobby. The occasional cinnamon paste tastes a bit better, I guess.

But toothpaste No. 27--this is a revelation. Tom's apricot toothpaste. It's fresh and clean-tasting, but not heavy-handed, with just a hint of licorice. It's like something you'd eat at Chez Panisse. I might actually look forward to toothbrushing.

So that's a winner in taste. But what about the other factors? Whitening. Cavity-fighting power. Price. The dispenser. The ethics of the manufacturer.

I could spend days researching and testing this decision. I feel like Buridan's ass. This is a donkey in a philosophical parable: He's hungry and thirsty and standing equidistant between a bucket of water and a bucket of food. He dies deciding.

The Internet has dozens of articles on comparative toothpaste studies. I consult consumersearch.com, which aggregates reviews from other consumer sites. "Colgate leads the pack," it reports. "Experts recommend Colgate Total most often." Okay. So maybe Colgate Total will be my pick.

But here's another key sentence: "Even the sites and publications which do make recommendations acknowledge that any approved toothpaste will benefit the consumer. Choices based on taste or consistency preferences are valid, and will not greatly affect oral health."

Okay, so taste it is. Apricot is the way to go. Then I look carefully at the apricot tube--there's no mention of ADA approval. I call the 800 number and find out approval is still "pending." Ugh. I call Thaler.

"I hate the taste of toothpaste," says Thaler. "If there's one that tastes like apricot, I'm there."

I promise to e-mail him the info.

"We don't want to make the mistake that only quantifiable things--like number of cavities--go into a rational decision," he says. "Rationality is all about trade-offs. Say I get a cavity once every decade. And with this toothpaste, I get a cavity once every nine years. The pleasure of the daily toothbrushing might make apricot the rational choice. Put it this way: If you choose the safest car even if it's ugly and no fun to drive, then it might not be rational."

The Texas Sharpshooter Fallacy

I'm turning into a bit of an asshole, it seems. I can't resist pointing out other people's cognitive biases.

My aunt Kate--an Orthodox Jew--sent me a viral e-mail today titled "God's Pharmacy." It's about how the shapes of food contain clues from God about nutrition.

"A sliced carrot looks like the human eye . . . science now shows carrots greatly enhance blood flow to the eyes."

"A tomato has four chambers and is red . . . the heart has four chambers and is red. Research shows tomatoes are loaded with lycopene and are indeed pure heart and blood food."

And on it went, with walnuts connected to brains and rhubarb resembling bones.

I reply, "Thanks, Kate!" I thought I'd start out polite, at least. "This seems like it's an example of the Texas Sharpshooter Fallacy." (A logical fallacy, as described on Wikipedia, in which information that has no relationship is interpreted or manipulated until it appears to have meaning. The name comes from a story about a Texan who fires several shots at the side of a barn, then paints a target centered on the hits and claims to be a sharpshooter.) "I'm not saying God doesn't exist, just that this food-shape idea is seriously flawed."

I press send. I try not to feel smug. It's just that these biases have given me a handy lens through which to view human thought. Simply being able to give a name--especially a cool one like Texas Sharpshooter--orders the chaos.

Kate replies that God designed the world in an infinitely subtle way to preserve our independence. So we must look deep to discover hidden truths.

I e-mail Kate again to say that the "God's Pharmacy" e-mail is related to another brain quirk. This one is called the Law of Similarity. If X and Y look similar, humans believe they are somehow related, whether they are or not.

This can be seen in my favorite experiment of all time: Psychologists asked students to eat a piece of fudge shaped like dog feces. The students couldn't do it--even though they knew rationally that it was just sugar, milk, butter, and cocoa. (This experiment, by the way, ruined my business plan for turd-shaped truffles.)

No response from Kate.

Spontaneous Trait Transference

I've been struggling with a work dilemma. The problem is, I've become what is officially known as a "blurb whore."

Because I've written two books about going on unlikely quests (one about reading the encyclopedia, the other about living by the Bible), I'm now linked to the genre. So I'm getting sent a lot of manuscripts with titles like Top Brass: One Man's Humble Quest to Master the Flügelhorn.

Unless I really dislike the book, I try to say something nice about it, even if it's to compliment the choice of typeface.

But now I've been asked to endorse a bunch of books that hit shelves at the exact same time as the paperback of my Bible book. And these books are about religion. Should I really be cannibalizing my own sales?

I think I'm going to have to be a dick and say no. Which gives me a stomachache. Until I read about a cognitive bias called Spontaneous Trait Transference. This is a fascinating fallacy with huge implications.

Here's how author Gretchen Rubin, of happiness-project.com, describes it:

"People will unintentionally associate what I say about the qualities of other people with my own qualities. So if I told Jean that Pat is arrogant, unconsciously Jean would associate that quality with me. On the other hand, if I said that Pat is brilliant or hilarious, I'd be linked to those qualities. What I say about other people sticks to me--even when I talk to someone who already knows me. So it behooves me to say only good things."

This has got to be the most wonderful brain quirk around. It's built-in biological karma. You trash-talk someone, it boomerangs back on you. You say kind things, you become a hero. So calling a book "ingenious" actually makes people think I'm ingenious. Being a blurb whore is good business.

Of course, I know, rationally, I could find good reasons why blurb whoring is terrible for business. But I don't want to. So I stop while I'm ahead.

The Endowment Effect

To get inspired, I've been watching Spock on YouTube and reading Star Trek scripts. Like this exchange:

Bailey: I happen to have a human thing called an adrenaline gland.

Spock: It does sound most inconvenient. . . . Have you considered having it removed?

It's a joke. But I actually think it's not a bad idea. At least for those of us who never go hiking and don't need to flee from grizzlies. I've become more and more wary of emotion. Scientists talk about System 1 and System 2. System 1 is the more ancient part of the brain that roughly corresponds to the "gut." System 2 is the more recent, evolutionarily speaking, that roughly corresponds to reason or the mind.

System 2 is Spock. System 1 is Homer. Some commentators have compared it to a monkey controlling a wild elephant. Author Gary Marcus, of the book Kluge, puts it this way: System 2 is "deliberative" and reflective. It's not always rational, but at least it tries. System 1 isn't always irrational, but it's "shortsighted" and "ancestral."

I realize Project Rationality is my attempt to live completely under System 2 and override the unstable lizard brain that is System 1.

This is disorienting to other people. Humans crave melodrama. Julie got upset with me today for not getting upset enough. I had done something dumb. I'd left our son's stroller in the back of a cab. It was a cheapo stroller, but still.

"Well, that was a mistake," I said when we realized it. "I will try not to do that again." (I do notice I'm using fewer contractions. Getting too into this Spock character?)

"That's it?" she asked.

"What do you want?"

"You're so blasé."

"You want theatrics?"

"I want you to say something like, 'Oh no, that's terrible. I can't believe I did that. I feel horrible.' "

I explained that I didn't feel that way. I felt annoyed at myself, and I vowed to try not to do it again. But I will probably forget other things in the future, so she should be prepared. In either case, throwing a hissy fit wouldn't get the stroller back nor help reform my behavior; it'd just create negative emotions. Plus, we overestimate the value of things we own--it's called the Endowment Effect.

My wife said our son needs to understand the value of objects.

I paused. "Point taken," I said. Our son is still a System 1 creature. "Next time, I will put on a show for our son."

My wife stomped out.

Lake Wobegon, Part 2

When I started this project, I thought I'd come to the conclusion that System 1 and System 2 are equally necessary. We need volcanic emotions as much as reasoned logic. But I've become more leery of System 1 every day. True, occasionally we need it. When we lose our balance and grab for the subway pole, that's instinct. We short-circuit the rational brain because there's no time for reason to get involved. But that's the exception. If I had to guess, I'd blame System 1 for 90 percent of wars and murders.

My ideal? A world of Spocks, but Spocks who are joyful and compassionate and life-loving. Spocks who brush with apricot toothpaste because it tastes delicious.

But I may have overestimated my ability to control System 1.

A week after my even-tempered stroller reaction, I'm at a restaurant with my son, waiting to play foosball. Two European teenagers are playing. They're accomplished foosballers, I can tell. They spin the rods expertly, scoring quickly, zipping the game along. Until they get to the last ball.

At which point they decide it'd be fun to draw the game out as long as possible. They pass the foosball back and forth slowly and carefully between their offensive lines.

"When will it be our turn?" asks my son.

"Soon."

Two minutes go by. Five minutes. My son has asked the above question a half dozen times by now.

"What's going on here?" I ask the teens.

"Vee are trying." They snicker--actually snicker. Then talk in German.

Ten minutes go by.

I know exactly what's happening in my brain as it's happening, and yet I feel like I can't stop it. My limbic system kicks in. My pulse triples.

"You are not trying. You are stalling."

"No, really. Vee are trying." More snickers.

My emotions have hijacked my cerebral cortex.

"You are bad people. Very bad people. What did your parents teach you?"

They ignore me. I flash to memories of being bullied as a kid. And now they're messing with my kid. The monkey is losing control of the elephant. The caveman is ascendant.

"You're nasty teenagers, and you're going to grow up into nasty adults. And let me tell you, with its history, your country doesn't need any more nasty people."

Did I just play the Nazi card? I did. And I'm not even 100 percent sure they're German. They sounded sort of German. But maybe they're Belgian.

My brother-in-law Eric was right. I suffer from the Lake Wobegon Effect. I overestimate my ability to be rational.

But you know what? I need it. I need the Lake Wobegon Effect. I need self-delusion. Otherwise I'd be so depressed about irrationality--and the general apocalyptic state of the world--that I couldn't function.

I have learned this much about myself and my deeply flawed brain: I have to believe, irrationally, against all evidence, that humans can be rational.

A.J. Jacobs

A.J. Jacobs is the author of 'The Puzzler,' along with several previous New York Times bestsellers such as 'The Year of Living Biblically' and 'Thanks a Thousand.' He lives in New York with his family and was once the answer to 1 Down in the New York Times crossword puzzle.