When Our Brains Short-Circuit by Nicholas Kristof

Our political system sometimes produces such skewed results that it’s difficult not to blame bloviating politicians. But maybe the deeper problem lies in our brains.

Evidence is accumulating that the human brain systematically misjudges certain kinds of risks. In effect, evolution has programmed us to be alert for snakes and enemies with clubs, but we aren’t well prepared to respond to dangers that require forethought.

If you come across a garter snake, nearly all of your brain will light up with activity as you process the “threat.” Yet if somebody tells you that carbon emissions will eventually destroy Earth as we know it, only the small part of the brain that focuses on the future — a portion of the prefrontal cortex — will glimmer.

“We humans do strange things, perhaps because vestiges of our ancient brain still guide us in the modern world,” notes Paul Slovic, a psychology professor at the University of Oregon and author of a book on how our minds assess risks.

Consider America’s political response to these two recent challenges:

1. President Obama proposes moving some inmates from Guantánamo Bay, Cuba, to supermax prisons from which no one has ever escaped. This is the “enemy with club” threat that we have evolved to be alert to, so Democrats and Republicans alike erupt in outrage and kill the plan.

2. The climate warms, ice sheets melt and seas rise. The House scrounges a narrow majority to pass a feeble cap-and-trade system, but Senate passage is uncertain. The issue is complex, full of trade-offs and more cerebral than visceral — and so it doesn’t activate our warning systems.

“What’s important is the threats that were dominant in our evolutionary history,” notes Daniel Gilbert, a professor of psychology at Harvard University. In contrast, he says, the kinds of dangers that are most serious today — such as climate change — sneak in under the brain’s radar.

Professor Gilbert argues that the threats that get our attention tend to have four features. First, they are personalized and intentional. The human brain is highly evolved for social behavior (“that’s why we see faces in clouds, not clouds in faces,” says Mr. Gilbert), and, like gazelles, we are instinctively and obsessively on the lookout for predators and enemies.

Second, we respond to threats that we deem disgusting or immoral — characteristics more associated with sex, betrayal or spoiled food than with atmospheric chemistry.

“That’s why people are incensed about flag burning, or about what kind of sex people have in private, even though that doesn’t really affect the rest of us,” Professor Gilbert said. “Yet where we have a real threat to our well-being, like global warming, it doesn’t ring alarm bells.”

Third, threats get our attention when they are imminent, while our brain circuitry is often cavalier about the future. That’s why we are so bad at saving for retirement. Economists tear their hair out at a puzzlingly irrational behavior called hyperbolic discounting: people’s preference for money now rather than much larger payments later.

For example, in studies, most Americans prefer $50 now to $100 in six months, even though that represents a 100 percent return.

Fourth, we’re far more sensitive to changes that are instantaneous than those that are gradual. We yawn at a slow melting of the glaciers, while if they shrank overnight we might take to the streets.

In short, we’re brilliantly programmed to act on the risks that confronted us in the Pleistocene Age. We’re less adept with 21st-century challenges.

At the University of Virginia, Professor Jonathan Haidt shows his Psychology 101 students how evolution has prepared us to fear some things: He asks how many students would be afraid to stand within 10 feet of a friend carrying a pet boa constrictor. Many hands go up, although almost none of the students have been bitten by a snake.

“The objects of our phobias, and the things that are actually dangerous to us, are almost unrelated in the modern world, but they were related in our ancient environment,” Mr. Haidt said. “We have no ‘preparedness’ to fear a gradual rise in the Earth’s temperature.”

This short-circuitry in our brains explains many of our policy priorities. We Americans spend nearly $700 billion a year on the military and less than $3 billion on the F.D.A., even though food-poisoning kills more Americans than foreign armies and terrorists. We’re just lucky we don’t have a cabinet-level Department of Snake Extermination.

Still, all is not lost, particularly if we understand and acknowledge our neurological shortcomings — and try to compensate with rational analysis. When we work at it, we are indeed capable of foresight: If we can floss today to prevent tooth decay in later years, then perhaps we can also drive less to save the planet.

Nuclear Bomb Tests Behind Ivory Dating by Julian Rush

Selling ivory is not illegal, providing it is from an elephant that died before 1947. But until now, proving the age of an item was notoriously difficult, relying on expert opinion.

Around the world, forgers have become adept at faking modern carvings to make them look old. Conservationists argued that sales on auction sites like eBay created a market that encouraged the forgers - and the poachers who kill elephants to meet the demand.

But now a sophisticated forensic scientific technique has been used for the first time in a court case of a woman accused of illegally offering carved ivory items for sale on eBay.

Following a tip-off from the National Wildlife Crime Unit, Hampshire Police raided the home of a woman from Aldershot in April 2007 and found 34 items. She was found not guilty at Winchester Crown Court last week.

The technique - radio carbon dating - is set to become an important weapon in the international fight against the illegal trade in animal parts and products that some suggest is worth billions of pounds a year.

For this case, Hampshire police called in the TRACE Wildlife Forensics Network who put them in touch with scientists in Scotland who specialise in radio carbon dating. It is usually used to date bones for archaeologists or rocks for geologists and uses the radioactive decay of carbon-14. 

Carbon-14 is a radioactive isotope of normal carbon and it occurs naturally in small quantities. It's taken up into the tissue and bones of every living plant and animal on Earth during life. At death, the carbon-14 starts to decay at a known rate, so by measuring the ratio of carbon-14 to normal carbon (which doesn't decay), scientists can determine the age of the sample.

That's fine for dating Neanderthal bones or an Egyptian mummy

Every Mushroom Cloud Has A Silver Lining

But in the 1950s and 60s, the fall-out from atmospheric nuclear bomb tests suddenly added extra carbon-14 to the atmosphere. All of us now have elevated levels of carbon-14 in our bodies as a result. And so too does every elephant, rhinoceros or walrus that's been alive since 1950. 

"If we find that the level of carbon-14 is enriched, then we know that elephant was alive in the nuclear era and therefore the ivory is illegal." Professor Gordon Cook, of the Scottish Universities Environmental Research Centre, who dated the ivory in this case, told Channel 4 News.

The spike is so high and so clear they can identify any organism that was alive after 1950.

Which, by chance, coincides almost exactly with the date for the age of ivory that can be legally sold. 

Though the woman was not convicted, TRACE, an international collaboration of campaigners, enforcement agencies and forensic scientists set up in 2006, believes the technique can be used successfully in future against the illegal wildlife trade like that in tiger body parts, rhino horn and scrimshaw. 

"We're now able to fully enforce the wildlife trade legislation. It opens the door for police to go after people trading illegally in ivory." said Dr. Ross McEwing of TRACE.

Professor Gordon Cook says the "nuclear bomb test" has wider uses. "It has huge potential. We've also looked at human teeth and we think we can tie down the year of birth by measuring the carbon-14. That, for something like mass graves, could be very important."

In January 2009, after a global campaign by environmentalists, eBay finally banned all sale of ivory.

The Triumph of the Random by Leonard Mlodinow

It was the summer of 1945, and World War II had ended. Former soldiers, including famous baseball stars, streamed back into America and into American life. Yankee slugger Joe DiMaggio was trying to be Yankee fan Joe DiMaggio, sneaking into a mezzanine seat with his 4-year-old son, Joe Jr., before rejoining his team. A fan noticed him, then another. Soon throughout the stadium people were chanting “Joe, Joe, Joe DiMaggio!” DiMaggio, moved, gazed down to see if his son had noticed the tribute. He had. “See, Daddy,” said the little DiMaggio, “everybody knows me!”

We all interpret the events around us according to our own worldview. By adulthood we’ve either gotten beyond the me-me-me context of 4-year-olds, or gone into politics. But drawing conclusions about data we encounter in sports, business, medicine and even our personal lives, we often make errors as significant as that of Joe Jr.

This holiday weekend—the Fourth of July—kicks off the home stretch of a two-month period that made Joe DiMaggio Sr. an icon of American culture. In 1941, a few months before Joe Jr. was born, and sandwiched between the day Hitler’s insane deputy Rudolf Hess parachuted into Scotland on an unauthorized peace mission and the day a secret British report concluded that the Allies could complete an atomic bomb ahead of Germany, there was a period of 56 successive Yankee games in which Joltin’ Joe had at least one hit.

DiMaggio’s hitting streak was an inspiration in troubled times. The pursuit of any record comes with pressure—Roger Maris lost some of his hair during his attempt to break Babe Ruth’s home-run record in 1961—but most records forgive you an off day as long as you compensate at other times. Not so with a streak, which demands unwavering performance. And so DiMaggio’s streak has been interpreted as a feat of mythic proportion, seen as a heroic, even miraculous, spurt of unrivaled effort and concentration.

But was it? Or was this epic moment simply a fluke?

Recent academic studies have questioned whether DiMaggio’s streak is unambiguous evidence of a spurt of ability that exceeded his everyday talent, rather than an anomaly to be expected from some highly talented player, in some year, by chance, something like the occasional 150-yard drive in golf that culminates in a hole in one. No one is saying that talent doesn’t matter. They are just asking whether a similar streak would have happened sometime in the history of baseball even if each player hit with the unheroic and unmiraculous—but steady—ability of an emotionless robot.

That randomness naturally leads to streaks contradicts people’s intuition. If we were to picture randomness, we might think of a graph that looks jerky, not smooth like a straight line. But random processes do display periods of order. In a toss of 100 coins, for example, the chances are more than 75% that you will see a streak of six or more heads or tails, and almost 10% that you’ll produce a streak of 10 or more. As a result a streak can look quite impressive even if it is due to nothing more than chance.

A few years ago Bill Miller of the Legg Mason Value Trust Fund was the most celebrated fund manager on Wall Street because his fund outperformed the broad market for 15 years straight. It was a feat compared regularly to DiMaggio’s, but if all the comparable fund managers over the past 40 years had been doing nothing but flipping coins, the chances are 75% that one of them would have matched or exceeded Mr. Miller’s streak. If Mr. Miller was really merely the goddess of Fortune’s lucky beneficiary, then one would expect that once the streak ended there would be no carryover of his apparent golden touch. In that expectation Mr. Miller did not disappoint: in recent years his fund has significantly lagged the market as he bet on duds like AIG, Bear Stearns, Merrill Lynch & Co. and Freddie Mac.

Of course a 10- or 15-game streak is a far cry from one of 56 games. This is where DiMaggio’s great ability plays a role, for if we are to compare DiMaggio’s performance to a coin, it must be a weighted coin. With a lifetime batting average of .325, DiMaggio had a better-than-75% chance of getting a hit in a game, while a balanced coin has but a 50% chance of success. Moreover, each year for over a century, hundreds of players have sought to achieve a streak such as DiMaggio’s. All those factors increase the odds that such a streak could have occurred by chance alone.

It’s not just the statisticians who wonder whether our heroes achieve records more often than coins. Psychologists, and, increasingly, economists, also puzzle over the seemingly discrete worlds of chance and perception. The fusion of those worlds was sanctified when half of the 2002 Nobel Prize in economics was awarded to psychologist Daniel Kahneman “for having integrated insights from psychological research into economic science, especially concerning human judgment and decision-making under uncertainty.”

Research into why people misinterpret streaks dates to 1985, and a paper co-authored by Mr. Kahneman’s regular collaborator, the late Amos Tversky, in the journal Cognitive Psychology. (No one doubts that, had he lived, Mr. Tversky would have shared in the prize). The paper was titled “The hot hand in basketball: On the misperception of random sequences.” Everyone who has ever played basketball knows the feeling of being “in the zone.” Your hand is on fire. You can’t miss. But are you feeling a true increase in ability, or is your mind inferring it because you just took a bunch of shots that, for whatever reason, went in?

If a person tossing a coin weighted to land on heads 80% of the time produces a streak of 10 heads in a row, few people would see that as a sign of increased skill. Yet when an 80% free throw shooter in the NBA has that level of success people have a hard time accepting that it isn’t. The Cognitive Psychology paper, and the many that followed, showed that despite appearances, the “hot hand” is a mirage. Such hot and cold streaks are identical to those you would obtain from a properly weighted coin.

Why do people have a hard time accepting the slings and arrows of outrageous fortune? One reason is that we expect the outcomes of a process to reflect the underlying qualities of the process itself. For example, if an initiative has a 60% chance of success, we expect that six out of every 10 times such an initiative is undertaken, it will succeed. That, however, is false. In order to warrant confidence that results reflect a deeper truth, you need many more trials than 10. In fact, one of the most counterintuitive features of randomness is that for a small number of trials, the results of a random process typically do not reflect the underlying probabilities.

For example, suppose we undertake an analysis of the resources, effort and ability of all the companies in the Fortune 500 and determine that every company has the same 60% chance of success in any given year. If we observe all the companies over a period of five years and the underlying probability of success were reflected in each company’s results, then over the five-year period every company would have three good years.

The mathematics of chance indeed dictate that in this situation the odds of a company having zero, one, two, four or five good years are lower than the odds of having three. Nevertheless it is not likely that a company will have three out of five good years—because there are so many of those misleading outcomes, their combined odds add up to twice the odds of having exactly three. That means that of the 500 companies, two-thirds will experience results that belie their underlying potential. In fact, according to the rules of randomness, nearly 50 of the companies will have a streak of either five good years, or five bad years, even if their corporate capacities were no better or worse than their counterparts’. And so if you judged the companies by their five-year results alone, you would probably over- or underestimate their true value.

In sports, the championship contenders are usually pretty evenly matched. But in baseball, even if one assumes that the better team has a lopsided 55/45 edge over the inferior one, the lesser team will win the seven-game World Series 40% of the time. That might seem counterintuitive, but you can look at it as follows. If you play a best-of-one game series, then, by our assumption, the lesser team will win 45% of the time. Playing a longer series will cut down that probability. The problem is that playing a seven-game series only cuts it down to 40%, which isn’t cutting it down by much. What if you demand that the lesser team win no more than 5% of the time—a constraint called statistical significance? The World Series would have to be the best of 269 games, and probably draw an audience the size of that for Olympic curling. Swap baseball for marketing, and you find a mistake often made by marketing departments: assuming that the results of small focus groups reflect a trend in the general population.

We find false meaning in the patterns of randomness for good reason: we are animals built to do just that. Suppose, for example, that you sit a subject in front of a light which flashes red twice as often as green, but otherwise without pattern. After the subject watches for a while, you offer the subject a reward for each future flash correctly predicted. What is the best strategy?

A nonhuman animal in this situation will always guess red, the more frequent color. A different strategy is to match your proportion of red and green guesses to the proportion you observed in the past, that is, two reds for every green. If the colors come in some pattern that you can figure out, this strategy will enable you to be right every time. But if the colors come without pattern you will do worse. Most humans try to guess the pattern, and in the process allow themselves to be outsmarted by a rat. (Those trying to time the market lately might wish they had let the rat take charge.) Looking for order in patterns has allowed us to understand the patterns of the universe, and hence to create modern physics and technology; but it also sometimes compels us to submit bids on eBay because we see the face of Jesus in a slice of toast.

Another reason we reject the power of randomness is our need for control. DiMaggio’s streak affects us because we all appreciate struggle and effort, triumphing despite huge odds. The notion that we might not have control over our environment, on the other hand, causes us to shudder.

Many studies illustrate how this basic aspect of human nature translates to a misperception of chance. For example, a group of Yale students were asked to predict the result of a series of coin tosses. The tosses were secretly rigged so that each student would have some success initially, but end up with a 50% success rate. The students were obviously aware of the random nature of their task. Yet when asked whether their performance would be hampered by distraction, and whether it would improve with practice, a significant number indicated that it would. Their deep-seated need for control trumped their intellectual understanding of the situation.

What about DiMaggio’s streak? There are many subtleties in randomness. For example, do you model a player as having a fixed batting average—that is, probability of a hit—or do you allow for the average to vary within the season, or even game to game? How do you treat the variation in at-bats, walks, etc.? The analyses can get long and the number of data needed unwieldy, so the jury is still out, but one of the studies, by Samuel Arbesman and Stephen H. Strogatz of Cornell University, attacked the problem by having a computer generate a mock version of each year in baseball from 1871 to 2005, based on the players’ actual statistics from that year. The scientists had the computer repeat the process 10,000 times, generating in essence 10,000 parallel histories of the sport.

The researchers found that 42% of the simulated histories had a streak of DiMaggio’s length or longer. The longest record streak was 109 games, the shortest, 39. In those 10,000 universes, many other players held the record more often than DiMaggio. Ty Cobb, for example, held it nearly 300 times.

DiMaggio’s streak, for better or worse, defined his life. Decades later, constantly hounded by autograph seekers, he wrote “If I thought this would be taking place due to the streak, I would have stopped hitting at 40 games.” He died just 10 years ago, at age 84. Joe Jr., who had trouble coping with his father’s fame, fell to a history of drug and alcohol abuse. He died five months after his father.

People are remembered—and often rewarded—not for their usual level of talent or hard work, but for their singular achievements, the ones that stand out in memory. It does no harm to view those achievements as heroic. But it does harm us to make investments or other decisions on a basis of misunderstanding. And it can be sad or even tragic when we interpret as failures plans or people simply because they did not succeed. Extraordinary events, both good and bad, can happen without extraordinary causes, and so it is best to always remember the other factor that is always present—the factor of chance.

Internet Groans Under Weight of Michael Jackson Traffic by Jacqui Cheng

The news of pop icon Michael Jackson's collapse and subsequent death sent ripples across the Web on Thursday afternoon, affecting numerous services and sparking yet another spam campaign. Twitter, Google, Facebook, various news sites, and even iTunes were practically crushed under the weight of the sudden spike in Internet traffic. The phenomenon may not be new on an individual level, but combined across services, it was truly one of the most significant in recent memory.

When news first broke that the Jackson had collapsed in his home, Twitter was immediately abuzz. There were several points when the Ars staff observed between 6,000 and 13,000 new tweets per minute mentioning Michael Jackson before Twitter began to melt down—all before anyone other than TMZ.com was reporting his death. Of course, most of us are intimately familiar with the famed Fail Whale at this point, though Twitter's meltdown was mostly reflected in a major slowing of the service and the inability to send new tweets.

In fact, Twitter cofounder Biz Stone told the L.A. Times that the news of Jackson's passing caused the biggest spike in tweets per second since the US Presidential Election. (Similarly, Facebook—also known as Wannabe Twitter—saw a spike in status updates that was apparently three times more than average for the site, though a spokesperson said the site remained free of performance issues.)

Google, on the other hand, began receiving so many searches for news about Jackson that it caused the search engine to believe it was under attack. The site went into self-protection mode, throwing up CAPTCHAs and malware alerts to users trying to find news. A Google spokesperson described the incident as "volcanic" compared to other major news events, confirming that there was a service slowdown for some time.

The spammers have come out in droves as well (never assume that someone isn't working on a way to instantaneously exploit the death of a major celebrity). Security researchers at Sophos put up a warning this morning saying that the first wave of spam messages has gone out claiming to have "vital information" regarding Jackson's death. There doesn't appear to be any call to action or URL, but is meant as a way to harvest e-mail addresses if recipients make the mistake of replying. We're sure this trend will continue in the coming days, not just about Michael Jackson, but also actress Farrah Fawcett (who also passed earlier in the day on Thursday), and former Tonight Show sidekick Ed McMahon.

Finally, Apple's iTunes Store appeared to experience some slowdowns upon the confirmation of Jackson's passing, though the service has been running smoothly since. Users, however, are paying (literally) tribute to MJ, as several of Jackson's hit singles are climbing into the iTunes Top 10, including "Man In the Mirror," "Thriller," and "Don't Stop 'Til You Get Enough." This is pretty impressive considering that he has made the list with three songs in less than 24 hours, competing with the likes of Black Eyed Peas' "Boom Boom Pow" (which has been close to the top of the iTunes Top 10 for what seems like three millennia—seriously, please quit buying it so it goes away).

Coupled with news that fans have been gathering in cities across the US to perform the renowned (if not a bit morbid, all things considered) Thriller zombie dance, we can't help but feel as if the user-driven age of the Internet will keep his memory alive in ways that past music icons have not had. (Only a couple of Ars staffers—we're looking at you Bangeman and Timmer—are old enough to remember the passing of Elvis Presley in 1977, which dominated newspapers and TV for days afterwards.) YouTube even has a Michael Jackson spotlight on its front page right now, so if you're feeling nostalgic, head on over and check out MJ's smooth moves from the days of yore. R.I.P., King of Pop.

The Ins and Outs of Borderline Tennis Calls by Alan Schwarz

When a line judge at Wimbledon rules on a hair-splittingly close call and says the ball is out, the inevitably disgruntled player should not only consider challenging the call for review by digital replay system.

He should consult a recent issue of Current Biology.

A vast majority of near-the-line shots called incorrectly by Wimbledon line judges have come on balls ruled out that were actually in, according to a study published in October by researchers at the University of California-Davis. To the vision scientist, the finding added to the growing knowledge of how the human eye and brain misperceive high-speed objects. To the tennis player, it strongly suggests which calls are worth challenging and which are best left alone.

The researchers identified 83 missed calls during the 2007 Wimbledon tournament. (Some were challenged by players and overruled, and others were later identified as unquestionably wrong through frame-by-frame video.) Seventy of those 83 calls, or 84 percent, were on balls ruled out — essentially, shots that line judges believed had traveled farther than they actually did.

Called perceptual mislocalization by vision scientists, this subconscious bias is known less formally to Wimbledon fans as “You cannot be serious!” — John McEnroe’s infamous dissent when, yes, a 1981 shot was ruled out. Now that players can resort to a more evolved appeal procedure, the researchers’ discovery suggests that players should generally use their limited number of challenges on questionable out calls rather those that are called in, because such out calls have a far better chance of being discovered as mistaken on review, then overturned.

“What we’re really interested in is how visual information is processed, and how it can be used to a player’s advantage,” said David Whitney, an associate professor at U.C.-Davis’s Center for Mind and Brain and the paper’s lead author. “There is a delay of roughly 80 to 150 milliseconds from the first moment of perception to our processing it, and that’s a long time. That’s one reason why it’s so hard to catch a fly — the fly’s ability to dance around is faster than our ability to determine where it is.”

This is the third Wimbledon in which players can challenge questionable calls for review by the Hawk-Eye system, which uses high-speed video cameras to record balls’ flight. (About 25 percent of all challenges result in overturned calls.) There is no cost to the player when a call is proved correct, but after three such episodes in a set a player may not challenge again. Whether through strategy or residual tennis etiquette, most players leave many challenges unused.

Theoretically, line judges should be equally prone to call an out ball in as they are an in ball out. But when objects travel faster than humans’ eyes and brains can precisely track them — for example, Andy Roddick’s 150-mile-per-hour serves — they are left having to fill in the gaps in their perception. In doing so they tend to overshoot the object’s actual location and think it traveled slightly farther than it truly did.

Both successful challenge calls as well as the overlooked mistakes that the researchers later identified were several times more likely to come on “long” calls than “in” calls. (The same pattern existed at Wimbledon last year, Whitney said, although the paper did not present that data.) So players are better off using as many challenges as possible on balls called out, because those are the calls most likely to be wrong; if a player thinks an “in” call was wrong, chances are his own eyes were as fooled as line judges’ sometimes are.

Without knowing it, tennis officials are already told to try to compensate for this mislocalization effect. Published instructions for United States Tennis Association line judges tell them to “focus your eyes on the portion of the line where the ball will land,” rather than attempt to track the ball in flight. “Get to the spot well before the ball arrives,” they are advised.

Rich Kaufman, the association’s director of officials and a linesman and chair umpire from 1976 to 1997, said that of all things “one of the hardest things to teach new linesmen is to take their eye off the ball.”

“I once asked an eye doctor, then what am I seeing on a bounce?” Kaufman said. “The doctor said that’s your brain working — you think you see the initial point of impact but it’s the blur of the entry and exit of the ball.”

A player using his knowledge of this effect in challenging calls could see a benefit of about one or two overturned points per match, Whitney said, plus any psychological boost from feeling vindicated rather than robbed. But Whitney added that understanding how the brain misperceives visual stimuli can help in more real-life matters, like the design and placement of high-speed safety equipment, automobile brake lights and warning signs of all types.

As for Wimbledon, it appears as if the new information can only help players, not the judges who vex them. Kaufman said: “You have to call what you see. Or what you think you see.”

Why the Eyes Have it by Christopher Chabris

Why are we ­humans so good at seeing in color? Why do we have eyes on the front of our heads rather than on the sides, like horses? And how is it that we find it so easy to read when written language didn’t even exist until a few thousand years ago—a virtual millisecond in evolutionary time?
Most of us, understandably, have never given much thought to questions like these. What is surprising is that most cognitive scientists ­haven’t either. People who study the brain generally ask how it works the way it does, not why. But Mark Changizi, a professor at Rensselaer ­Polytechnic Institute and the author of “The Vision ­Revolution,” is indeed a man who asks why, and lucky for us: His ideas about the brain and mind are fascinating, and his explanations for our habits of seeing are, for the most part, persuasive.
Mr. Changizi takes care not to call himself a practitioner of evolutionary psychology. This is the one discipline of the mind sciences that focuses on why questions, but it often answers them by telling just-so stories that cannot be ­disproved. (Why do men have better spatial ability than women? Because a long time ago, in Africa, men needed spatial skills to track prey and to kill at a distance—a plausible theory but one that is difficult to test with experiments.) Instead Mr. Changizi calls ­himself a “theoretical neuroscientist,” seeking explanations for the design of the mind that are based on mathematical and physical analysis. He has his own stories, it is true, but they are grounded solidly in neuroscience, and they are backed up by data about a surprising range of human activities, from ­the colors found in historical ­costumes to the ­correspondence between the shapes found in written letters and the shapes found in ­nature.
Let’s start with the question of color. It is such a natural part of our visual experience that we don’t stop to wonder why we can see it at all. ­Without color television there would have been no “Miami Vice,” of course, but were we really missing out on so much when we had only black and white? The consensus explanation for our superior ability to perceive color is that primates evolved it to see fruit—you can’t order dinner if you can’t read the menu.
Mr. Changizi thinks otherwise. He proposes that color vision is useful for distinguishing the changes in other ­people’s skin color—changes that are caused by shifts in the volume and oxygenation levels of the blood. Such shifts, like blushing, often signal emotional states. The ability to see them is adaptive because it helps an observer to “read” states of mind and states of health in others, information that is in turn useful for predicting their behavior.
Our brains evolved in a time when people lived their entire lives without ever seeing someone with a skin color different from their own. Thus the skin color we grow up seeing, Mr. Changizi says, is “neutral” to us: It serves as a kind of baseline from which we notice even minor deviations in tint or hue. Almost every language has distinct words for some 11 basic colors, but none of them aptly describe the look of skin, which seems colorless (except in our recent multicultural societies, where skin color is newly prominent). As one might expect, primates without color vision tend to have furry faces and hands and thus less need to perceive skin color; ­primates with color vision are more “naked” in this respect, humans most of all.
James Steinberg
Conventional wisdom may be similarly misleading when it comes to binocular vision. It is said that we have two forward-facing eyes, which send our brains two separate images of almost everything in our field of view so that the brain can compare those images to estimate the distance of objects—a generally useful thing to know. But people who are blind in one eye, Mr. Changizi notes, can perform tasks like driving a car by using other cues that help them to judge distance. He offers a different explanation: that two eyes give us a sort of X-ray vision, allowing us to see “through” nearby objects to what is beyond.
You can experience this ability yourself by closing one eye and holding your forefinger near your face: It will appear in your field of vision, of course, and it will block what lies beyond or behind it. If you open both eyes, though, you will suddenly perceive your finger as transparent—that is, you will see it and see, ­unblocked, the full scene in front of you. Mr. Changizi observes that an animal in a leafy environment, with such an ability, gains an advantage: It can lurk in tall grass and still see what is “outside” its hiding place. He correlates the distance between the eyes and the density of vegetation in the habitats of animals and finds that animals with closer-set eyes do tend to live in ­forests rather than on plains.
As for reading, Mr. Changizi stops to observe how remarkable this ability is and how useful, giving us access to the minds of dead people (i.e., deceased writers) and permitting us to take in words much faster than we can by merely listening to them. He claims that we learn to read so easily because the symbols in our written alphabets have evolved, over many generations, to resemble the building blocks of natural scenes—­exactly what previous millennia of evolution adapted the brain to perceive quickly. A “T,” for example, appears in nature when one object overlaps ­another, like a stone lying on top of a stick. With statistical analysis, Mr. Changizi finds that the contour patterns most common in nature are also most common in letter shapes.
Mr. Changizi has more to say about our visual experience—about optical illusions, for instance, which he sees as artifacts of a trick the brain uses to cope with the one-tenth of a second it takes to process the light that hits our eyes and to determine what is actually in front of us. He calls for a new academic discipline of “visual linguistics,” and he tells us why there are no ­species with just one eye.
What does all this add up to? Provocative hypotheses but not settled truth—at least not yet. As a theoretician, Mr. Changizi leaves it to others to design experiments that might render a decisive ­verdict. Someone else will have to study how accurately people can perceive mental states from shifting skin tones, and someone else will have to ­determine whether, in most cases, looking at another ­person’s skin adds any useful information to what is easily known from facial expression, tone of voice and body ­language.
Still, the novel ideas that Mr. Changizi outlines in “The Vision Revolution”—together with the evidence he does present—may have a big effect on our understanding of the human brain. Their implication is that the environments we evolved in shaped the design of our visual system according to a set of deep principles. Our challenge now is to see them clearly.

I never thought I'd be rooting for Iran by Bradley Burston

I never thought I'd be rooting for Iran 

I am in awe of the courage of the people of Iran They are giving the world hope. They are teaching a shocking lesson about truth. They embody freedom. And, perhaps hardest to grasp, for those of us who live in the Middle East, they are putting their very lives on the line not for the sake of some ferociously sectarian End of Days, but for the most profoundly radical notion of all - a better life. 

Every person who has taken to the streets to demand what their government promised them, free and fair elections, did so knowing that police or secret police could arrest them, act to cripple their careers, or outright gun them down