SAN FRANCISCO, Nov. 11 — Bonnie Brown was fresh from a nasty divorce in 1999, living with her sister and uncertain of her future. On a lark, she answered an ad for an in-house masseuse at Google, then a Silicon Valley start-up with 40 employees. She was offered the part-time job, which started out at $450 a week but included a pile of Google stock options that she figured might never be worth a penny.

After five years of kneading engineers’ backs, Ms. Brown retired, cashing in most of her stock options, which were worth millions of dollars. To her delight, the shares she held onto have continued to balloon in value.

“I’m happy I saved enough stock for a rainy day, and lately it’s been pouring,” said Ms. Brown, 52, who now lives in a 3,000-square-foot house in Nevada, gets her own massages at least once a week and has a private Pilates instructor. She has traveled the world to oversee a charitable foundation she started with her Google wealth and has written a book, still unpublished, “Giigle: How I Got Lucky Massaging Google.”

When Google’s stock topped $700 a share last week before dropping back to $664 on Friday, outside shareholders were not the only ones smiling. According to documents filed on Wednesday with the Securities and Exchange Commission, Google employees and former employees are holding options they can cash in worth about $2.1 billion. In addition, current employees are sitting on stock and unvested options, or options they cannot immediately cash in, that together have a value of about $4.1 billion.

Although no one keeps an official count of Google millionaires, it is estimated that 1,000 people each have more than $5 million worth of Google shares from stock grants and stock options.

One founder, Larry Page, has stock worth $20 billion. The other, Sergey Brin, has slightly less, $19.6 billion, according to Equilar, an executive compensation research firm in Redwood Shores, Calif. Three Google senior vice presidents — David Drummond, the chief legal officer; Shona Brown, who runs business operations; and Jonathan Rosenberg, who oversees product management — together are holding $160 million worth of Google stock and options.

“This is a very rare phenomenon when one company so quickly becomes worth so much money,” said Peter Hero, senior adviser to the Silicon Valley Community Foundation, which works with individuals and corporations to support charitable organizations in the region. “During the boom times, there were lots of companies whose employees made a lot of money fast, like Yahoo and Netscape. But the scale didn’t approach Google.”

Indeed, Google has seemed to exist in its own microclimate, with its shares climbing even as other technology stocks have been buffeted by investor skittishness. The stock touched an all-time high of $747.24 on Tuesday before falling more than $83 a share during the week to close at $663.97 on Friday. But even after that sell-off, the stock has risen more than 44 percent, or $203 a share, this year.

The days are long gone when people like Ms. Brown were handed thousands of Google options with the exercise price, or the pre-determined price that employees would pay to buy the stock, set in pennies. Nearly half of the 16,000 employees now at Google have been there for a year or less, and their options have an average exercise price of more than $500. But those who started at the company a year ago, or even three months ago, are seeing their options soar in value.

Several Google employees interviewed for this article say they do not watch the dizzying climb of the company’s shares. When it comes to awareness of the stock price, they say, Google is different from other large high-tech companies where they have worked, like Microsoft, where the day’s stock price is a fixture on many people’s computer screens.

At Google, the sensibility is more nuanced, they say. “It isn’t considered ‘Googley’ to check the stock price,” said an engineer, using the Google jargon for what is acceptable in the company’s culture. As a result, there is a bold insistence, at least on the surface, that the stock price does not matter, said the engineer, who did not want to be named because it is considered unseemly to discuss the price.

Others admit that, when gathered around the espresso machine it is hard to avoid the topic of their sudden windfalls.

“It’s very clear that people are taking nicer vacations,” said one Google engineer, who asked not to be identified because it is also not Googley to talk about personal fortunes made at the company. “And one of the guys who works for me but has been there longer showed up at work in a really, really nice new car.”

The rise in Google’s stock is affecting the deepest reaches of the company. The number of options granted to new employees at Google usually depends on the position and the salary level at which the employee is hired, and the value is usually based on the price of the stock at the start of employment.

The average options grant for a new Google employee — or “Noogler” — who started in November 2006 was 685 shares at a price of roughly $475 a share. They also would have received, on average, 230 shares of stock outright that will vest over a number of years.

The Nooglers might not be talking about second homes in Aspen or personal jets, but they are talking about down payments on a first home, new cars and kitchen renovations. Internal online discussion groups about personal finance are closely read.

Google, like many Silicon Valley companies, gives each of its new employees stock options, as well as a smaller number of shares of Google stock, as a recruiting incentive.

The idea of employment at a place with such a high stock price is appealing, but it can also make the company less attractive to a new hire. Jordan Moncharmont, 21, a senior at Stanford University who was given stock options after he started working at Facebook part time, said Google’s high stock price can be a disincentive to a prospective hire as it translates to a high exercise price for options. “You’d have to spend a boatload of cash to exercise your options,” he said.

Mr. Moncharmont said he did not join Facebook to get rich, though he knows his Facebook options could make him wealthy someday.

When Ms. Brown left Google, the stock price had merely doubled from its initial offering price of $85. So Ms. Brown is glad she ignored the advice of her financial advisers and held onto a cache of stock.

As the stock continues to defy gravity, Ms. Brown, whose foundation has its assets in Google stock, can be more generous with her charity. “It seems that every time I give some away, it just keeps filling up again,” she said. “It’s like an overflowing pot.”

The wealth generated by options is giving a lot of people like Ms. Brown the freedom to leave and do whatever they like.

Ron Garret, an engineer who was Google’s 104th employee, worked there for a little more than a year, leaving in 2001. When he eventually sold all his stock, he became a venture capitalist and a philanthropist. He has also become a documentary filmmaker and is currently chronicling homelessness in Santa Monica, Calif.

“The stock price rise doesn’t affect me at all,” he said, “except just gazing at it in wonderment.”

Educators and psychologists have long feared that children entering school with behavior problems were doomed to fall behind in the upper grades. But two new studies suggest that those fears are exaggerated.

One concluded that kindergartners who are identified as troubled do as well academically as their peers in elementary school. The other found that children with attention deficit disorders suffer primarily from a delay in brain development, not from a deficit or flaw.

Experts say the findings of the two studies, being published today in separate journals, could change the way scientists, teachers and parents understand and manage children who are disruptive or emotionally withdrawn in the early years of school. The studies might even prompt a reassessment of the possible causes of disruptive behavior in some children.

“I think these may become landmark findings, forcing us to ask whether these acting-out kinds of problems are secondary to the inappropriate maturity expectations that some educators place on young children as soon as they enter classrooms,” said Sharon Landesman Ramey, director of the Georgetown University Center on Health and Education, who was not connected with either study.

In one study, an international team of researchers analyzed measures of social and intellectual development from over 16,000 children and found that disruptive or antisocial behaviors in kindergarten did not correlate with academic results at the end of elementary school.

Kindergartners who interrupted the teacher, defied instructions and even picked fights were performing as well in reading and math as well-behaved children of the same abilities when they both reached fifth grade, the study found.

Other researchers cautioned that the findings, being reported in the journal Developmental Psychology, did not imply that emotional problems were trivial or could not derail academic success in the years before or after elementary school.

In the other study, researchers from the National Institute of Mental Health and McGill University, using imaging techniques, found that the brains of children with attention-deficit hyperactivity disorder developed normally but more slowly in some areas than the brains of children without the disorder.

The disorder, also known as A.D.H.D., is by far the most common psychiatric diagnosis given to disruptive young children; 3 percent to 5 percent of school-age children are thought to be affected. Researchers have long debated whether it was due to a brain deficit or to a delay in development.

Doctors said that the report, being published in The Proceedings of the National Academy of Sciences, helps to explain why so many children grow out of the diagnosis in middle school or later, often after taking stimulant medications to improve concentration in earlier grades.

The findings in the first study grew out of a collaboration among a dozen leading researchers to reassess data from six large child-development studies performed since 1970. Each of these six studies tracked hundreds of children from an early age through elementary school on a number of measures, including reading and math skills, emotional stability and concentration, or attention. Most of the studies used teacher reports to gauge students’ emotional and social progress and their ability to pay attention when asked.

The researchers adjusted the findings to eliminate the influence of factors like family income and family structure.

While there was little correlation between behavior problems in kindergarten and later academic success, the researchers did find that scores on math tests at ages 5 or 6 were highly correlated with academic success in fifth grade. Kindergarten reading skills and scores on attention measures — where youngsters with A.D.H.D. falter — also predicted later academic success, but less strongly than math scores did. The pattern was about the same in girls as in boys, and for children from affluent families as well as those from lower-income groups.

The authors of the study suggested that preschool programs might consider developing more effective math training. The findings should also put to rest concerns that boys and girls who are restless, disruptive or withdrawn in kindergarten are bound to suffer academically.

“For kindergarten, it appears teachers are able to work around these behavior problems in a way that enables kids to learn just as much as other kids with equal levels of ability,” said the lead author, Greg J. Duncan, a professor of human development and social policy at Northwestern University.

The findings, Dr. Duncan said, have been “very controversial among developmental psychologists who have seen the paper.”

One who is concerned, Ross Thompson, a professor of psychology at the University of California, Davis, said it would be a mistake to conclude from the results that programs to guide preschoolers’ emotional development were not helpful.

“That would be a double whammy for really difficult kids,” Dr. Thompson said, “to have no help managing their behavior and then — wham! — to get labeled as problem kids as soon as they enter school.”

In the second study, government psychiatric researchers compared brain scans from two groups of children: one with attention deficit disorder, the other without. The scientists had tracked the children — 223 in each group — from ages 6 to 16, taking multiple scans on each child.

In a normally developing brain, the cerebral cortex — the outer wrapping, where circuits involved in conscious thought are concentrated — thickens during early childhood. It then reverses course and thins out, losing neurons as the brain matures through adolescence. The study found that, on average, the brains of children with A.D.H.D. began this “pruning” process at age 10 ½, about three years later than their peers.

About 80 percent of those with attention problems were taking or had taken stimulant drugs, and the researchers did not know the effect of the medications on brain development. Doctors consider stimulant drugs a reliable way to improve attention in the short term; the new study is not likely to change that attitude.

But the greatest delays in brain maturation were found in precisely those areas of the cortex most involved in attention and motor control, said the lead author of the study, Dr. Philip Shaw, a psychiatrist at the National Institute of Mental Health.

“Those are exactly the areas where we would expect to find differences,” Dr. Shaw said.

Doctors cannot diagnose attention deficit or any other psychiatric disorder with imaging technology, in part because brains vary so much that a single series of images can seldom reveal who has a disorder. The new findings suggest that searching for a clear abnormality or flaw is the wrong approach, at least for attention problems.

“The basic sequence of development in the brains of these kids with A.D.H.D. was intact, absolutely normal,” Dr. Shaw said. “I think this is pretty strong evidence we’re talking about a delay, and not an abnormal brain.”

About three in four children do grow out of the problem by early adulthood, he said.

Your first reaction upon meeting Yue Minjun might be, yes, it is indeed he! The face with the enigmatic, jaw-breaking grin, perhaps the most recognizable image in contemporary Chinese painting, is a self-portrait.

“Yes, it’s me,” Mr. Yue said in a recent interview, and he smiled, though in a gentler, less face-splitting fashion than the man in his paintings — the one who drifts Zelig-like past various familiar backgrounds making a sardonic, or perhaps ironically despairing, comment on the passing scene.

Mr. Yue, 45, was in New York in October for the opening of an exhibition of his paintings and sculptures that continues through Jan. 6 at the Queens Museum of Art. The show, “Yue Minjun and the Symbolic Smile,” is the first American museum exhibition of Mr. Yue’s work and further evidence of his remarkable rise in the superheated field of Chinese contemporary art.

A few years ago, Mr. Yue was eking out a precarious existence in one of Beijing’s artist colonies, trying to figure out a way to weave China’s tumultuous experience into his works. Now, largely on the strength of that signature grin, he has achieved stardom internationally.

Most conspicuously, one of his paintings, “Execution” (1995), a satirical Pop Art-like version of Manet’s “Execution of Maximilian” that was inspired by the 1989 crackdown in Tiananmen Square, sold for $5.9 million last month at an auction at Sotheby’s in London. It was a record sum for a contemporary Chinese painting. For Mr. Yue, the huge sums suddenly commanded by his works — “The Pope” (1997), depicting him as a prelate, went for $4.3 million in June — have involved a readjustment.

“I never thought about this in the past,” he said. “What was important to me was the creation part of painting. But it seems that something has changed. Maybe it’s the way money is becoming more important in society.”

He is not always comfortable with how his work is analyzed. The mesmerizing enigma of that reddish face painted over and over again, with the wide laugh and the eyes tightly shut from the hilarious strain, is subject to a multitude of interpretations. One Chinese art critic has identified the artist as a member of what he calls the school of “cynical realism,” though Mr. Yue doesn’t feel that he belongs to a school or movement and he doesn’t think he’s cynical.

“I’m actually trying to make sense of the world,” he said. “There’s nothing cynical or absurd in what I do.”

Mr. Yue was born in 1962 in the far northern Heilongjiang Province of China and as a child moved to Beijing with his parents. He studied oil painting at the Hebei Normal University and graduated in 1989, when China was rocked by student-led demonstrations and their suppression on Tiananmen Square in June of that year.

“My mood changed at that time,” he said. “I was very down. I realized the gap between reality and the ideal, and I wanted to create my own artistic definition, whereby there could be a meeting with social life and the social environment.”

“The first step,” he added, “was to create a style to express my feelings accurately, starting with something that I knew really well —myself.” That was the first step toward forging what has become the image that has now made him famous. The second step was to devise the laugh, which, he said, was inspired by a painting he saw by another Chinese artist, Geng Jianyi, in which a smile is deformed to mean the opposite of what it normally means.

“So I developed this painting where you see someone laughing,” he said. “At first you think he’s happy, but when you look more carefully, there’s something else there.”

“A smile,” Mr. Yue said, “doesn’t necessarily mean happiness; it could be something else.”

The smile has been variously interpreted as a sort of joke at the absurdity of it all, or the illusion of happiness in lives inevitably heading toward extinction.

Karen Smith, a Beijing expert on Chinese art, suggests that Mr. Yue’s grin is a mask for real feelings of helplessness.

“In China there’s a long history of the smile,” Mr. Yue said. “There is the Maitreya Buddha who can tell the future and whose facial expression is a laugh. Normally there’s an inscription saying that you should be optimistic and laugh in the face of reality.”

“There were also paintings during the Cultural Revolution period, those Soviet-style posters showing happy people laughing,” he continued. “But what’s interesting is that normally what you see in those posters is the opposite of reality.”

Mr. Yue said his smile was in a way a parody of those posters. But, since it’s a self-portrait, it’s also necessarily a parody of himself, he added.

“I’m not laughing at anybody else, because once you laugh at others, you’ll run into trouble, and can create obstacles,” he said. “This is the way to do it if you want to make a parody of the things that are behind the image.”

The real reason he paints himself is that it gives him a greater margin for freedom of expression, he explained.

The work at the Queens Museum ranges from a grouping of 20 life-size terra cotta soldiers, grinning versions of the famous statues unearthed years ago at the tomb of China’s first emperor, to a painting of a laughing version of himself holding another self-image aloft in front of the Statue of Liberty.

There is also a series called “Hats,” in which Mr. Yue has painted himself in all sorts of headgear, from an American football helmet to a peaked cap of a soldier in the Chinese People’s Liberation Army, with that unvarying laugh on his face.

“It’s not a denial of reality but a questioning of it,” Mr. Yue said of his work in general. “And that laugh — anybody who’s gone through Chinese recent experience would understand it.”