Monday, July 01, 2002

Human Intuition: The Brain Behind the Scenes

Intuition: Its Powers and Perils

By: David G. Myers, Ph.D.

Today “intuition is hot,” reports Myers, but what exactly is it? Calling on research about how our brains process vast amounts of information “off screen” and hundreds of experiments in cognitive psychology, Myers posits answers that take the mystery out of intuition, giving us, instead, amazement at the powers of our brain. But be careful—power doesn’t guarantee infallibility. “My geographical intuition tells me,” writes Myers, “that Reno is east of Los Angeles, that Rome is south of New York, that Atlanta is east of Detroit, but I am wrong, wrong, and wrong.”

David G. Myers has two big messages for his readers. The first is that intuition really exists, and it is important. Brain processes that occur automatically, without our conscious awareness, constitute much of our mental life. Recent brain research has revealed the nature of some of these powerful unconscious processes, which range from our instantaneous emotional reactions to danger, to implicit memory, to subliminal perception. In hundreds of experiments over the past decade, cognitive science has shown that these and other processes profoundly shape our thoughts, attitudes, and emotions—often in ways of which we are unaware.

But Myers’s second message is that, even after we have dismissed the scientifically baseless claims of psychic intuition and many so-called “intuitives,” intuition is prone to error. He demonstrates that real, everyday intuition, if not vetted by conscious thinking, frequently leads us astray in our professional work, relationships, assessments of risks, and even sports, investment, and gambling. These are the pitfalls of “thinking without awareness.”

In these excerpts from the book’s introduction and first chapter, Myers calls upon brain science to show us the scope and power of the brain “off-stage, out of sight.”


Excerpted from Intuition: Its Powers and Perils by David G. Myers. © 2002 Yale University Press, New Haven, Connecticut. Reprinted with permission. 

My geographical intuition tells me that Reno is east of Los Angeles, that Rome is south of New York, that Atlanta is east of Detroit. But I am wrong, wrong, and wrong. “The first principle,” said Einstein’s fellow physicist Richard Feynman, “is that you must not fool yourself—and you are the easiest person to fool.”

For Webster and for this book, intuition is our capacity for direct knowledge, for immediate insight without observation or reason. “Intuitive thinking is perception-like, rapid, effortless,” notes Princeton University psychologist Daniel Kahneman. By contrast, “deliberate thinking is reasoning-like, critical, and analytic.”  Intuition authors and trainers—“intuitives,” as they call themselves—seem largely oblivious to psychology’s new explorations of how we process information. Are their intuitions about intuition valid? Is our consciousness sometimes invaded by unbidden truth, which is there for us to behold if only we would listen to the still small voice within? Or are their intuition writings to cognitive science what professional wrestling is to athletics? Do they offer little more than a make-believe world, an illusory reality in substitution for the real thing?

The emerging understanding, as we will see, is double-sided. “There are trivial truths and great truths,” declared the physicist Niels Bohr. “The opposite of a trivial truth is plainly false. The opposite of a great truth is also true.” And so it is with human intuition, which has surprising powers and perils. On the one hand, recent cognitive science reveals a fascinating unconscious mind—another mind backstage— that Freud never told us about. More than we realized over a decade ago, thinking occurs not on stage, but off stage, out of sight...


Blindsight. Having lost a portion of their brain’s visual cortex to surgery or stroke, people may be consciously blind in part of their field of vision. Shown a series of sticks in the blind field, they report seeing nothing. Yet when asked to guess whether the sticks are vertical or horizontal, they may unerringly offer the correct response. When told, “you got them all right,” they are astounded. These people clearly know more than they know they know. They may reach to shake an outstretched hand that they cannot see. There are, it seems, little minds—“parallel processing” systems—operating unseen.

Indeed, “sight unseen” is how University of Durham psychologist David Milner describes the brain’s two visual systems—“one that gives us our conscious perceptions, and one that guides our actions.” The second he calls the “zombie within.” Milner describes a brain-damaged woman who can see the hairs on the back of a hand and yet be unable to recognize a hand. Asked to use her thumb and forefinger to estimate an object’s size, she can’t do it— though when she reaches for the object her thumb and forefinger are appropriately placed. She knows more than she is aware of.

Prosopagnosia. Patients with this disorder have suffered damage to a part of the brain involved in face recognition. After losing the pertinent temporal lobe area, patients may have complete sensation but incomplete perception. They can sense visual information—indeed, may accurately report the features of a face yet be unable to recognize it. When shown an unfamiliar face, they do not react. When shown a loved one’s face, however, their body displays recognition. Their autonomic nervous system responds with measurable perspiration and speeded pulse. What the conscious mind cannot understand, the heart knows.

Everyday perception. Consider your own taken-for-granted capacity to intuitively recognize a face. As you look at a photo, your brain acts like a multitasking computer. It breaks the visual information into subdimensions, such as color, depth, movement, and form, and works on each aspect simultaneously, using different neural networks, before reassembling the components. (Damage the pertinent neural network and you may become unable to perceive a sub-dimension, such as movement.) Finally, your brain compares the reconstructed image with previously stored images. Voila! Instantly and effortlessly you recognize, among billions of humans, someone you’ve not seen in five years.

Neural impulses travel a million times slower than a computer’s internal messages, yet our brain humbles any computer with its instant recognition. “You can buy a chess machine that beats a master,” notes vision researcher Donald Hoffman, “but can’t yet buy a vision machine that beats a toddler’s vision.” If intuition is immediate knowing, without reasoned analysis, then perceiving is intuition par excellence.

So, is human intelligence more than logic? Is thinking more than ordering words? Is comprehension more than conscious cognition? Absolutely. Cognitive psychologist George Miller embodied this truth by telling of two passengers leaning against the ship’s rail, staring at the sea. “‘There sure is a lot of water in the ocean,’ said one. ‘Yes,’ answered his friend, ‘and we’ve only seen the top of it.’”


Imagine (or ask someone to imagine) folding a sheet of paper on itself 100 times. Roughly how thick would it be?

Given our year with 365 days, a group needs 366 people to ensure that at least two of its members share the same birthday. How big must the group be to have a 50 percent chance of finding a birthday match?

Imagine yourself participating in this study, patterned after a 1930s experiment by psychologist Lloyd Humphreys. On each of 100 trials, you are asked to guess whether a light that goes on 70 percent of the time will go on. You get a dollar each time your guess (“yes” or “no”) is correct. Visualize the first ten trials.

Once again, our intuitions usually err. Given a 0.1-millimeter-thick sheet, the thickness after 100 folds, each doubling the preceding thickness, would be 800 trillion times the distance between the earth and the sun. Only twenty-three people are needed to give better than even odds of any two people having the same birthday. (Look out at a soccer match with a referee and the odds are 50-50 that two people on the field have the same birthday.) And though people typically guess “yes” about 70 percent of the time, their intuitions leave them with emptier pockets— about $58—than if they simply guess “yes” all the time, producing about $70.*

Ah, but shall we say with some postmodernists that intuitive truth is self-validating, and that we must not judge it by the canons of westernized logic? No. With these mind teaser problems, rational analysis defines truth. On the perceptual problems, the ruler rules: it measures an objective reality. On the little gambling game, the rare person who follows logic leaves with enough money to take friends out to a lobster dinner, while the intuitive and friends at the next table can afford only spaghetti...

My own field of psychological science has sometimes confirmed popular intuitions. An enduring, committed marriage is conducive to adults’ happiness and children’s thriving. The media modeling of violent and sexually impulsive behaviors do affect viewers’ attitudes and actions (though the same studies contradict people’s intuitions that it’s only others who are influenced). Perceived freedom and feelings of control are conducive to happiness and achievement. But at the same time, our unaided intuitions may tell us that familiarity breeds contempt, that dreams predict the future, and that high self-esteem is invariably beneficial—ideas that aren’t supported by the available evidence. Even the California Task Force to Promote Self-Esteem acknowledged in its report that the “intuitively correct” presumption—that high self-esteem leads to desirable behaviors—has been but weakly confirmed. (It is true that those with high self-esteem are less at risk for depression, but high self-esteem also has a dark side. Much violence results from the puncturing of inflated egos.)

Recent research also relegates other intuitively correct axioms of pop psychology to the dustbin.

  • Although genetic predispositions and peer and media influences shape children, direct parental nurture has surprisingly little effect on their developing personalities and tastes. (Adopted siblings do not develop more similar personalities as a result of being reared in the same home. And identical twins are not more alike in personality if reared together than if reared in separate homes.)
  • People typically do not repress acutely painful or upsetting experiences. Holocaust survivors, children who have witnessed a parent’s murder, and rape victims remember the horror all too well. 

Experiments have similarly deflated people’s intuitions that quartz crystals uplift their spirits, that subliminal self-help tapes have reprogrammed their unconscious mind, and that “therapeutic touch” (moving hands near the body) has curative effects. (Those given fake crystals or supposed subliminal tapes, for example, exhibit the same results.)

 “Science,” said Richard Feynman, “is a long history of learning how not to fool ourselves.”... 


Has anyone ever told you that you are amazing? Well, you are. You process vast amounts of information off screen. You effortlessly delegate most of your thinking and decision making to the masses of cognitive workers busily at work in your mind’s basement. Only the really important mental tasks reach the executive desk, where your conscious mind works. When you are asked, “What are you thinking?” your mental CEO answers, speaking of worries, hopes, plans, and questions, mindless of all the lower-floor laborers.

This big idea of contemporary psychological science—that most of our everyday thinking, feeling, and acting operate outside conscious awareness—“is a difficult one for people to accept,” report John Bargh and Tanya Chartrand, psychologists at New York University. Our consciousness is biased to think that its own intentions and deliberate choice rule our lives (understandably, since tip-of-the-iceberg consciousness is mostly aware of its visible self). But consciousness overrates its own control. Take something as simple as speaking. Strings of words effortlessly spill out of your mouth with near-perfect syntax (amazing, given how many ways there are to mess up). It’s as if there were servants downstairs, busily hammering together sentences that get piped up and fluidly shoved out of your mouth. You hardly have a clue how you do it. But there it is....


Some things we know we know, but we don’t know how we know them. Consider your absorption of language. If you are an average secondary school graduate you know some 80,000 words (likely an underestimate given that you’re reading this book). That averages (from age 1 to 18) nearly 5,000 words learned each year, or 13 each day! How you did it— how the 5,000 words a year you learned could outnumber by so much the roughly 200 words a year that your schoolteachers consciously taught you—is one of the great human wonders. Before you could add 2 + 2 you were creating your own original and grammatically appropriate sentences. Your parents probably would have had trouble stating the rules of syntax. Yet while barely more than a toddler you intuitively comprehended and spoke with a facility that would shame a college student struggling to learn a foreign language or a scientist struggling to simulate natural language on a computer.

Even infants—well before they have begun thinking in words—possess striking intuitive capacities. We are born preferring sights and sounds that facilitate social responsiveness. As newborns, we turned our heads in the direction of human voices. We gazed longer at a drawing of a face-like image than at a bull’s-eye pattern, and longer at a bull’s-eye pattern (which has contrasts much like those of the human eye) than at a solid disk. We preferred to look at objects eight to twelve inches away, which, wonder of wonders, just happens to be the approximate distance between a nursing infant’s eyes and its mother’s.

Our perceptual abilities develop continuously during the first months of life. Within days of birth, our brain’s neural networks were stamped with the smell of our mother’s body. Thus, a week-old nursing baby, placed between a gauze pad from its mother’s bra and one from another nursing mother, will usually turn toward its own mother’s pad. A three-week-old infant, if given a pacifier that turns on recordings of either its mother’s voice or a female stranger’s, will suck more vigorously when it hears its now-familiar mother.

Babies also have an intuitive grasp of simple laws of physics. Like adults staring in disbelief at a magic trick, infants look longer at a scene of a ball stopping in midair, a car seeming to pass through a solid object, or an object that seems to disappear. Babies even have a head for numbers. Researcher Karen Wynn showed five-month-old infants one or two objects. Then she hid the objects behind a screen, sometimes removing or adding one through a trap door. When she lifted the screen, the infants often did a double take, staring longer when shown a wrong number of objects. Like animals’ native fear of heights, this is intuitive knowledge—unmediated by words or rational analysis.


For more than a century, we’ve known that the brain’s two sides serve differing functions. Accidents, strokes, and tumors in the left hemisphere generally impair activities of the rational, verbal, nonintuitive mind, such as reading, writing, speaking, arithmetic reasoning, and understanding. Similar lesions in the right hemisphere seldom have such dramatic effects.

By 1960 the left hemisphere (or “left brain”) was well accepted as the dominant or major hemisphere, and its quieter companion as the subordinate or minor hemisphere. The left hemisphere is rather like the moon’s facing side—the one easiest to observe and study. It talks to us. The other side is there, of course, but hidden.

When surgeons first separated the brain’s hemispheres as a treatment for severe epilepsy, they effectively created a small population of what have been called the most fascinating people on earth—split-brain people who are literally of two minds. The peculiar nature of our visual wiring enables researchers to send information to either the patients’s left or right brain by having the patient stare at a spot and then flashing a stimulus to the right or left of it. (They could do this with you, too, but in your intact brain the telltale hemisphere that received the information would instantly call the news to its partner across the valley. Split-brain surgery severs the phone cables—the corpus collosum—across the valley.) Finally, the researchers quiz each hemisphere separately.

In an early experiment, psychologist Michael Gazzaniga asked split-brain patients to stare at a dot as he flashed HE•ART. Thus HE appeared in their left visual field (which transmits to the right brain) and ART in the right field (which transmits to the left brain). When he then asked them what they had seen, the patients said they saw ART and so were startled when their left hands (controlled by the right brain) pointed to HE. Given an opportunity to express itself, each hemisphere reported only what it had seen. The left hand intuitively knew what it could not verbally report.

Similarly, when a picture of a spoon was flashed to their right brain, the patients could not say what they saw. But when asked to identify what they had seen by feeling an assortment of hidden objects with their left hands, they readily selected the spoon. If the experimenter said, “Right!” the patient might reply, “What? Right? How could I possibly pick out the right object when I don’t know what I saw?” It is, of course, the left brain doing the talking here, bewildered by what it’s nonverbal right brain quietly knows.

These experiments demonstrate that the right brain understands simple requests and easily perceives objects. In fact, the right brain is superior to the left at copying drawings, recognizing faces, perceiving differences, sensing and expressing emotion.

Although the left brain is adept at literal interpretations of language, the right brain excels in making subtle inferences. If “primed” with the flashed word foot, the left brain will be especially quick to then recognize the closely associated word heel. But if primed with foot, cry, and glass, the right brain will more quickly recognize another word that is distantly related to all three: cut. And if given a verbal problem—what word goes with high, district, and house?—the right brain more quickly than the left recognizes that the solution is school. As one patient explained after suffering right-brain stroke damage, “I understand words, but I’m missing the subtleties.” Thus, the right brain helps us modulate our speech to make meaning clear—as when we ask “What’s that in the road ahead?” instead of “What’s that in the road, a head?”

Some split-brain surgery patients have temporarily been bothered by the unruly independence of their left hand, which might unbutton a shirt while the right hand buttoned it.

Some split-brain surgery patients have temporarily been bothered by the unruly independence of their left hand, which might unbutton a shirt while the right hand buttoned it, or put groceries back on the shelf after the right hand put them in the cart. It was as if each hemisphere was thinking “I’ve half a mind to wear my green (blue) shirt today.” Indeed, said Nobel laureate psychologist Roger Sperry, split-brain surgery leaves people “with two separate minds.” (Reading these reports, I imagine a split-brain person enjoying a solitary game of “rock, paper, and scissors”—left hand versus right.)

When the two minds are at odds, the left brain acts as the brain’s press agent, doing mental gymnastics to rationalize unexplained action. If the right brain commands an action, the left brain will intuitively justify it. If the right brain is commanded to laugh, the patient will respond with laughter. The left brain, when asked why the laughter, will rationalize, perhaps pointing to the “funny research.” If a patient follows an order sent to the right brain (“Walk”), the left brain will offer a ready explanation (“I’m going into the house to get a Coke”). Michael Gazzaniga concludes that the left brain is an “interpreter” that instantly constructs theories to justify our behavior. We humans have a quick facility for constructing meaning.

Most of the body’s paired organs—kidneys, lungs, breasts—perform identical functions, providing a backup should one side fail. Not so the brain’s two halves. They are a biological odd couple, serving differing functions, each seemingly with a mind of its own. From simply looking at the similarly shaped hemispheres, who would suppose that they contribute uniquely to the harmony of the whole?

And not even Freud (who didn’t anticipate the cool intelligence of the hidden mind) could have supposed that our brains are humming with so much resourceful activity outside our conscious awareness, and that our interpretive left brain, grasping at straws, can so speedily intuit false explanations for our behavior. Beneath the surface there is much intelligence, and above the surface there is much self-delusion.


My ninety-three-year-old father recently suffered a small stroke that has had but one peculiar effect. His genial personality is intact. He is as mobile as before. He knows us, and while poring over family photo albums can reminisce in detail. But he has lost most of his facility for laying down new memories of conversations and everyday episodes. He cannot tell me what day of the week it is. He enjoys going out for a drive and commenting on what we’re seeing, but the next day he cannot recall our going anywhere. Told repeatedly of his brother-in-law’s death, he would still express surprise on learning the news.

Oliver Sacks tells of another such memory-loss patient, Jimmie, who thirty years after suffering brain damage in 1945 would still, when asked who is president, answer “Harry Truman.” Sacks showed Jimmie a photo from National Geographic. “What is this?” he asked.

“It’s the moon,” Jimmie replied.

“No, it’s not,” Sacks answered. “It’s a picture of the earth taken from the moon.”

“Doc, you’re kidding? Someone would’ve had to get a camera up there!”


“Hell! You’re joking—how the hell would you do that?” Jimmie’s wonder was that of a bright young man from fifty-five years ago reacting with amazement to his travel back to the future.

Careful testing of these unique people reveals something even stranger: Although incapable of recalling new facts or anything they have recently done, Jimmie and other similarly amnesiac people can learn. Once shown hard-tofind figures in pictures (Where’s Waldo?), they can quickly spot them again later. They can learn to read mirror-image writing or do a jigsaw puzzle (after denying that they’ve ever seen the task before). They have even been taught complicated job skills. However, they do all these things with no awareness of having learned them.

These curious findings challenge the idea that memory is a single, unified system. Instead, we seem to have two systems operating in tandem. Whatever has destroyed conscious recall has left unconscious learning intact. These patients can learn how to do something—called implicit memory (or procedural memory). But they cannot know and declare that they know— called explicit memory (or declarative memory). Having read a story once, they will read it faster a second time, showing implicit memory. But there will be no explicit memory, for they cannot recall having seen the story before. After playing golf on a new course, they will forget the experience completely, yet the more they play the course, the more their game will improve. If repeatedly shown the word perfume, they will not recall having seen it. But if asked what word comes to mind in response to the letters per, they surprise themselves by saying perfume, readily displaying their learning. They retain their past but do not explicitly recall it. Intuitively, they know more than they are aware.

This dual explicit-implicit memory system helps explain “infantile amnesia”: The reactions and skills we learned during infancy—how to walk, whether to trust or fear others—reach far into our future. Yet as adults we recall nothing (explicitly) of our first three years. Although benefitting from a legacy of collected intuitions—our perceptions of distance, our sense of good and bad, our preference for familiar foods, people, and places—our conscious minds draw a blank for those early years. Infantile amnesia occurs because we index so much of our explicit memory by words that nonspeaking toddlers have yet to learn, and also because a crucial brain region for laying down explicit memories (the hippocampus) is one of the last brain structures to mature. We are amnesic for much of our past. Yet some of what we don’t explicitly recall we implicitly, intuitively remember.


...If the old psychoanalytic methods don’t reliably reveal the unconscious mind’s working, the new cognitive science does. Consider, first, our capacity for divided attention. You surely are aware that your conscious attention is selective. It’s in but one place at a time. If you doubt this, try (assuming you are right-handed) moving your right foot in a smooth counterclockwise circle while writing the number 3 repeatedly with your right hand. You can easily do either—but not at the same time. Or if you are musically trained, try tapping a steady three beats to the measure with your left hand while tapping four times with your right hand. Unless they become automatic with practice, such tasks require conscious attention, which can be in only one place at a time. Consciousness focuses us. If time is nature’s way of keeping everything from happening at once, then consciousness is nature’s way of keeping us from thinking everything at once.

This classic perceptual illusion, which shifts from the silhouette of  a vase to the silhouette of two faces as our attention flickers back and forth, illustrates that conscious attention is highly focused and selective. Unconscious brain activities, by contrast, operate in parallel, supporting immensely complex activities such as speaking grammatically or returning a tennis serve, which require simultaneous, coordinated, largely automatic processes.

Perceptions, too, come to us moment by moment, one perception being lifted from our mind’s magic slate as the next appears. Because conscious attention is selective, we see the familiar reversible figure (above) only one way at a time, before the perception flits away and the alternate replaces it...

But now things get really interesting, for it turns out that we can, nevertheless, process and be influenced by unattended information. Let someone from the hubbub of unattended party noise speak your name and instantly your attention shifts. You weren’t listening to that speaker, but the downstairs laborers watching the radar screens noticed the blip— a signal amid the noise—and instantly alerted your mental CEO. In a dichotic listening experiment they will do the same when detecting an emotion-arousing word, such as one previously associated with electric shock. Likewise, in a “dichoptic viewing” experiment—with differing images seen by the two eyes—only one will be visible to you, though your brain’s radar technicians will do a rudimentary scan of the other for any important information. Ergo, you are, right now, processing much information outside your awareness...

Priming experiments reveal how one thought, even outside of awareness, influences another thought or action. Priming is the awakening of associations. In yet another experiment, people asked to complete a sentence containing words like old, wise, and retired afterward walked more slowly to the elevator than those not primed—and without any awareness of walking slowly or of the high frequency of words related to aging.

The experiments have their counterparts in everyday life:

  • Watching a scary movie alone at home can prime our thinking, activating emotions that cause us to interpret furnace noises as those of an intruder.
  • For many psychology students, reading about psychological disorders primes how they interpret their own anxieties and gloomy mood. Reading about disease similarly primes medical students to worry about their congestion, fever, or headache.
  • Ask people to pronounce the word spelled by S-H-O-P and then ask them (or ask yourself) what they do when they come to a green light. Many will answer “stop,” and then will sheepishly grin when realizing their priming-induced error.

The take home lesson: Although perception requires attention, unattended stimuli can subtly affect us. Moreover, implanted ideas and images can automatically—unintentionally, effortlessly, and without awareness—prime how we interpret and recall events.

In a host of new studies, the effects of priming surface even when the stimuli are presented subliminally—too briefly to be perceived. What’s out of sight need not be out of mind. An electric shock, too slight to be felt, increases the perceived intensity of a later shock. An imperceptibly flashed word, bread, primes people to detect a related word, such as butter, more quickly than bottle or bubble. A subliminal color name facilitates speedier identification when the color itself appears on a computer screen, while an unseen wrong name delays color identification. In each case, an invisible image or word primes a response to a later question.


...We have sampled but a few of the hundreds of 1990s experiments exploring the relative contribution of our two ways of knowing— automatic (unconscious) and controlled (conscious). When meeting and greeting people, when pondering and predicting their behavior, when screening and stereotyping strangers, to what extent are we guided by knee-jerk intuitions rather than by deliberate reasoning? To a great extent, surmises John Bargh, a leading researcher, “automatic, nonconscious processes pervade all aspects of mental and social life.” As Galileo “removed the earth from its privileged position at the center of the universe,” so Bargh sees automatic thinking research “removing consciousness from its privileged place.” The purpose of consciousness, he theorizes, is “to connect a parallel mind to a serial world” (his italics). And the unconscious is less simpleminded and irrational than some researchers contend, argues Bargh. Unconscious, intuitive inclinations detect and reflect the regularities of our personal history. Thanks to a repository of experience, a tennis player automatically—and intelligently—knows just where to run to intercept the ball, with just the right racquet angle. As Venus Williams smacks the ball, conscious attention and unconscious perception and coordination integrate seamlessly. The result is her near-perfect intuitive physics. 

*Guessing “yes” 70 percent of the time would produce about $49 for correct yes’s (.7 x 70 = 49) and about $9 for correct no’s (.3 x 30 = 9).

About Cerebrum

Bill Glovin, editor
Carolyn Asbury, Ph.D., consultant

Scientific Advisory Board
Joseph T. Coyle, M.D., Harvard Medical School
Pierre J. Magistretti, M.D., Ph.D., University of Lausanne Medical School and Hospital
Helen Mayberg, M.D., Icahn School of Medicine at Mount Sinai 
Bruce S. McEwen, Ph.D., The Rockefeller University
Donald Price, M.D., The Johns Hopkins University School of Medicine
Charles Zorumski, M.D., Washington University School of Medicine

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