After suffering a brain hemorrhage, 7-year-old Charlotte Neve slipped into a coma. The British girl was unconscious for several days and doctors feared she wouldn’t recover. Her mother, Leila Neve, was at her bedside when Adele’s “Rolling in the Deep” started playing on the radio. Leila and Charlotte often sang the song together and Leila began singing along.

Then something remarkable happened: Charlotte smiled. Within two days, she could speak and get out of bed. Why does music seem to help "awaken" some people from their comas?

“It was a salient stimulus, something that she is familiar with, like [her] name,” says Dr. Emery Neal Brown, professor of anesthesia at Mass General Hospital and Harvard Medical School and professor of computational neuroscience at MIT.

Brown suspects Charlotte recovered some brain functioning prior to hearing the Adele song, but it was imperceptible. When she heard the song, she smiled and eventually woke because it held meaning for her (that's the salient stimulus part).  

“Maybe people have function recovered and we don’t know how to communicate with them,” he says, explaining a salient stimulus varies by person.

“Whenever memories have an emotional context to them, they tend to hold much more power in the brain and tend to be processed differently,” says Dr. Javier Provencio, director of the Neurological Critical Care Unit at Cleveland Clinic.

Robin Gibb of the Bee Gees woke from his coma when his family played music for him — music for a professional musician who sang with his brothers would have deep meaningful connections in the brain, sparking a reaction. But for someone who plays tennis or rides horses, a song might not encourage a response. 

But sometimes, music causes a reaction because the brain processes songs differently than spoken language. In these cases, the region of the brain responsible for song might be working better while the language lags behind.

“We clearly process music and tonal things differently than language. There are patients [who had strokes] who cannot talk but can still sing,” says Provencio.

The left cerebral hemisphere controls language, while the right processes song and music. Patients who have damage in the left might respond better to song.

“They lose the ability to talk and understand. Music therapy is really useful because it is used in the non-dominate hemisphere,” says Dr. James Bernat, professor of neurology and medicine at Geisel School of Medicine at Dartmouth and a member of the American Academy of Neurology.

Music therapists such as Lee Anna Rasar at the University of Wisconsin Eau Claire often use music to try to evoke responses from comatose patients. She notes that songs are most effective “if the music is something they knew before that already had meaning.”

All the physicians agree that doctors still have limited understanding of whether someone will recover from a coma, but if Charlotte wasn’t already healing, she wouldn’t have smiled at the song.

“Even in a coma, it’s quite common that these people improve spontaneously,” says Bernat. “They wake up and start responding. It isn’t outside the range of what is expected that there would be improvement over time.”

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• You will never get 'Call Me Maybe' out of your head
• Can't carry a tune? You may be amusic

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Reuters file photo

Singer Carly Rae Jepsen just met you. And this is crazy. But here she is singing at the MuchMusic Video Awards in Toronto on Sunday, so call her, maybe?

It seems impossible to hide from Carly Rae Jepsen's “Call Me Maybe.” Someone auto-tuned videos of President Obama so he performs it; The Roots and Jimmy Fallon played it with toy musical instruments; the Harvard baseball team, the Southern Methodist University women’s rowing team, and the Miami Dolphin cheerleaders all danced to the ditty; and the bubble gum pop song has taken over all the airwaves.

And maybe your brainwaves -- does it seem like “Call Me Maybe” is on repeat in your head? You’re not alone; you have an earworm. Earworms, or involuntary imagery of music, burrow their way into the subconscious, making a home in the brain. And "Call Me Maybe" is arguably the earwormiest song in recent memory. 

“Earworms is a colloquial name for a phenomena in music psychology—an experience when you get a song or a piece of song such as chorus [stuck in your head] without a willing attempt to experience a musical memory,” says Lassi A. Liikkanen, who published two papers about earworms recently in the journals Psychology of Music and Musicae Scientiae.   

People frequently experience earworms after hearing a new songs and recognizing a few snippets of lyrics and melody.  

“Involuntary imagery of music is based on our skill to remember music, but for some reason feels out of control. But is perfectly normal,” explains, Liikkanen, a researcher at Helsinki Institute for Information Technology HIIT in Finland.

Songs such as “Call Me Maybe” or fun's “We Are Young” seem to pop into our brains against our will. Seeing an album cover or recalling a memory associated with a song can induce an earworm. Liikkanen, who surveyed more than 12,000 Finish Internet users about earworms, found that nearly 90 percent of people experience involuntary imagery of music.

“Some times these involuntary music experiences are tied to a life experience and it is congruent with mood,” he says. “Even if you haven’t heard a song for weeks, months, decades [hearing the song sparks] a key memory.”

He discovered that women catch earworms more than men and younger generations have the bug more frequently than older folks. While there is little evidence about why these differences occur, Liikkanen has a few theories.

Women might be more attuned to their mental lives, possibly connecting songs with meaningful moments more frequently. When it comes to earworms and older people, it seems that older folks listen to music less and might not have as great of memory retention as they once had.

In general, people who play or write music hear earworms more than those simple music listeners.

“A lot of the great composers claim they were hearing the music in their heads … it happens with the not so [great] composers,” Liikkanen says. While the more musical education one has the more involuntary imagery of music occurs at some point it evens out—people with the highest levels of music education reported fewer recurrent earworms.

Those with a form of OCD might hear earworms an excessive amount and people suffering auditory hallucinations sometimes also hear snippets of songs repeatedly. In these cases, Liikkanen says people should consult a psychiatrist for treatment.

“People consider [earworms] entertaining and fun occasions when they emerge,” he says. “Music is wonderfully complicated in human psychology.”  

Dying to extract "Call Me Maybe" from your brain? It's not so simple. Liikkanen suggests avoiding all music and cues connected with the song. Cues can be as seemingly insignificant as hearing the title of the song or the artist's name -- so you'll need a moratorium on anything beginning with the words "call me." Good luck with that. 

You can enable the Earworm Clinic application on Facebook to learn more about your earworms and provide information for Liikkanen. 

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• Shriek, sob, swoon: What causes Bieber fever?

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“I know only two tunes: one of them is ‘Yankee Doodle,’ and the other isn’t,” quipped Ulysses S. Grant. Grant famously disdained military music and many speculate that the 18th President of the United States suffered from tone-deafness or amusia.

“Amusia is a general term that applies to a group of musical deficits,” says Daniel J. Levitin, James McGill Professor of Psychology and Behavioural Neuroscience at McGill University in Montreal. 

Tone-deafness and amusia remain misunderstood. Bad singers could be one of four types—people unable to hear pitch; people who can’t capture rhythm; people who sing in a monotone; and people with voices that others don’t prefer, says Levitin. He peppers his explanation with song, singing “Twinkle, Twinkle Little Star” monotonically then performing it as if he is Bob Dylan (he does a pretty passable impression!).   

 “[Dylan] actually hits all the pitches, he is very precise; he has an unusual voice,” Levitin says. Critics call Dylan tone deaf simply because they dislike his voice.

Being a bad vocalist does not mean one is truly amusic. Being amusic means a person lacks musical ability; she might not be able to distinguish pitch or create different sounds.

“Normal people have some musical ability—if I play you a piece of music and I miss a note, you would know something wrong with that. Amusics can’t [tell],” says Psyche Loui, a neurology instructor at Beth Israel Deaconess Medical Center and Harvard Medical School in Boston. “The main compliant is that they cannot sing in tune.”

Anywhere from 4 to 9 percent of the population suffers from amusia. It’s difficult to obtain solid estimates because people dubbed tone-deaf earn the distinction because of terrible singing, not because they have been tested for amusia. (And these are real tests, including this one from the Music and Neuroimaging Laboratory, where Loui works http://musicianbrain.com/pitchtest/).

Loui says experts remain unsure about what causes amusia, but most believe a combination of environmental and genetic factors lead to disruptions in the brain, contributing to “unawareness and poor memory for sounds, especially pitches.”

Being amusic makes life tricky (and not just for those who suffer through a screeching rendition of “Call Me Maybe” at karaoke).

Many Asian and African languages are tonal and one word possesses different meanings based on how it’s pronounced. Loui, whose native language is Cantonese, provides an example. If she says ‘ma’ one way it means mother, if she says it with different inflection it means horse. Amusics who speak tonal languages are often unfairly pegged as having learning disabilities.

“If you cannot perceive tone, you can’t produce it,” says Loui.

In most languages, being unable to understand inflection or pitch can lead to misunderstandings, says Levitin. “A lot of emotion and intention is conveyed by tone,” he says.

People understand sarcasm because they hear the tone. For a person unable to discern such nuances, a conversation can be confusing.  

“[Amusia] is definitely a real phenomena and has neural underpinnings,” says Loui.

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TODAY

A Justin Bieber fan gets hysterical at the concert.

They’d been camping on the streets of New York City for three days -- throngs of teen and tween girls, who had gone without showers (except for the ones that fell from the sky) in the hopes of getting a front row glimpse of their favorite teenage heartthrob.

And when everyone’s imaginary “Boyfriend” Justin Bieber took the stage this morning to play a mini-concert for TODAY, these super-fans did what teen groupies have done for eternity: they screamed, they cried, they quivered. 

So what's behind all the shrieking and sobbing, the shaking and swooning? Is there a physiological explanation for this fan-demonium or is it simply tween and teen girls gone wild?

"It's basically a group response set off by emotions and hormones," says Dr. Sarah Pitts, a specialist in adolescent medicine at Boston Children's Hospital.

TODAY

The crowd surrounds The Biebs.

A lot has to do with what's happening in the heads of tweens and teens. In those early adolescent years from 10 to 14, kids are searching for new people to love outside of their family and they might glom on to a celebrity crush, suggests Pitts.

In addition, being around groups of young people may also make this behavior more "contagious" during a phase when peer pressure rules. For the 15- and 16-year old Bieber fans in the audience, there's also the growing interest in forming relationships and sexual attraction that fuels the emotional excitement of seeing your teen idol.

"The teen brain is still significantly changing and not yet in its final form," points out Pitts. "And that affects how teens respond to the world around them."

Young girls are especially prone to getting emotional and when they get excited, they cry "happy tears."

"I don't know that there's a scientific basis for that," admits Pitts. "It comes down to the chemistry in our brains and nerves."

As for keeling over, Pitts says fainting is really common in teens, more so in females.

If a young Bieber fan has been standing outside for hours, and they're sleep deprived and very excited, and perhaps also hungry and cold, then passing out is a possibility. It's more of an emotional faint, in which falling over is actually protective allowing blood to quickly shunt back to the brain.

Of course, this generation is not the first to weep, screech, and faint at its teenage heartthrobs. These behaviors go way back. If it wasn't the Biebs who was bringing on the waterworks and hysteria, it was the Jonas Brothers, or ‘N Sync; the Jackson 5, the Beatles or Elvis.

So why don't young boys scream and swoon at a Miley Cyrus or Selena Gomez concert? "Boy's brains and hormones are wired differently," says Pitts. And while it's culturally OK for girls to cry, that's not the behavioral norm for guys.

Then again, maybe it's just that chicks are the bigger Bieber "believers." 

More on Justin Bieber:

• Surviving a concert camp-out: 7 tips from Bieber fans
• Matt Lauer joins Twitter (with some help from Bieber)
• Video: Justin and 'Mrs. Bieber' chat with Matt Lauer
• Watch his TODAY performance

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On Thursday evening in Bern, Switzerland, Myanmar’s Nobel Peace Prize award-winner, Aung San Suu Kyi, discontinued her press conference after 15 minutes. Suu Kyi paused the questioning as a sickened look crossed her face. She grabbed a bag and vomited into it. She left the conference apologizing for the sudden eruption, um, interruption.

She began the press conference by noting she felt exhausted and struggled to adjust to the time difference. Can fatigue -- plus a bad case of jet lag -- really make you throw up?    

“A combination of exhaustion and experiencing a big time difference could certainly lead someone to vomit. This may be even more true if they are very warm or under a great deal of stress,” says Dr. Rachel Vreeman via email. Vreeman is co-author of the book “Don’t Swallow your Gum!: Myths, Half-Truths, and Outright Lies About Your Body and Health” and an assistant professor of pediatrics in the Children's Health Services Research Program at the Indiana University School of Medicine.

Exhaustion causes a variety of symptoms, some more common than others. People suffering from a lack of sleep might feel tremors, headache, concentration problems, elevated blood pressure, achy muscles and psychosis.

“Exhaustion can absolutely make someone feel nauseous and even lead to vomiting. Sometimes, the body responds to fatigue -- especially extreme fatigue -- with symptoms of nausea. Stomach upset, including nausea, vomiting, and diarrhea, can also be symptoms of jet lag,” says Vreeman.

Extreme fatigue sparks intervention from two opposing systems in the body -- the parasympathetic nervous system and the sympathetic nervous system. The sympathetic nervous system helps people in tough situations by triggering the flight or fight response, which throws the body into alert mode. The parasympathetic nervous system controls at-rest functions like digestion and salivation.  

“Depending on which system is reacting the most to the stress and fatigue -- your sympathetic system that creates a flight-or-fight response or your parasympathetic system, which causes you to do things like salivate and have relaxed bowels -- you might experience nausea and vomiting in a particular situation,” Vreeman says. 

According to an AP article, Suu Kyi experienced recent bouts of illness when traveling. The slight, 66-year-old political activist felt weak and threw up twice while campaigning for parliament.

Suu Kyi is not alone when it comes to public purging. When George H.W. Bush visited Japan in 1992, he famously spewed on the lap of Prime Minister Kiichi Miyazawa during a state dinner. Bush claimed to be exhausted from an earlier tennis bout and perhaps afflicted by the flu.

Athletes frequently lose their lunches -- some more than others. Pete Sampras and Michael Jordon both spewed on the court, but it seems that former Philadelphia Eagle, Donovan McNabb made blowing chunks a habit. McNabb puked at the end of the fourth quarter during Super Bowl XXXIX. The quarterback said he felt nauseated all game, but teammates claimed McNabb threw up frequently during games and blamed it on exhaustion. 

Vreeman says if a person vomits once because of exhaustion, it doesn’t mean it will occur again. People can prevent the negative effects of exhaustion by sleeping more, staying hydrated, and wearing comfortable clothing. If it seems that jet lag is the problem, people can take sleep aids or melatonin to reduce the impact of time change.

Related:

• 'Tired' Suu Kyi vomits at news conference 

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With the school year winding down, students and teachers from coast-to-coast are letting out a huge sigh of relief. And whether you're feeling relief because you're retiring this June, found your misplaced cell phone, or got back a negative medical test result, the truth is scientists know surprisingly little about this common feeling.

Recently two researchers studied this emotion to help paint a clearer picture of it. But what exactly is relief -- aside from that phew-inducing feeling as if a heavy weight has been lifted off your shoulders?

"Relief involves a contrast between a good feeling right now and a bad feeling that either never happened or has ended," says lead author Kate Sweeny, PhD, an assistant professor of psychology at the University of California, Riverside. "It's that sense that things are better right now than they could otherwise be."

In the study, published in the May issue of Psychological Science, researchers revealed that relief is not one simple emotion. It's actually more complex and takes on two distinct forms that affects us in different ways.

One form is near-miss relief, which is what you may feel when you narrowly avoid something terrible. It's the dodged-a-bullet feeling after you swerve to avoid a fender-bender or finding your keys and realizing you're not locked out.

The second kind is task-completion relief, from persevering through a difficult experience. Examples include wrapping up a stressful project at work, reaching the end of a tough school year, or training for and running a marathon.

To study relief, one experiment involved nearly 80 college students who were told they would be singing Morris Albert's corny song "Feelings" into an audio-recorder with someone observing their performance. Half of the volunteers -- the task-completion group -- sang. The other half -- the near-miss group -- were told the recorder broke so they wouldn't have to sing.

Afterwards, both groups completed surveys about the emotions they were feeling.

Researchers found the students who felt near-miss relief from not singing tended to think about how things could have turned out worse ("I'm glad no one had to listen to my awful voice.") Because their thoughts focus on the near miss, people in this situation turn inward and feel emotionally isolated from other people who did not share this experience, according to Sweeny.

In contrast, someone who has crooned "Feelings" also feels relieved that it's over. But they can focus less on the now completed task and their thoughts turn to moving forward, freed of the burden they once faced. "These people have no reason to feel socially isolated," explains Sweeny. "They may feel even more connected to other people because they are no longer distracted by the onerous task."

This study confirmed that all relief is not created equal, and the emotion serves a psychological purpose.  "We believe it may play a crucial role in helping people to improve themselves following an experience of relief," says Sweeny.

Feeling relieved to be done with something difficult or unpleasant can motivate people to stick with tough tasks or endure them in the future, Sweeny suggests. And she says that feeling relieved to have avoided something terrible can motivate people to avoid the near miss altogether in the future.

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Besides the cards, cake, candles, and gifts, there might be one more unexpected surprise in store for you on your birthday -- a higher risk of dying.

A new study suggests that men and women are 14 percent more likely to die on their birthday than any other day of the year.  This effect was strongest in people aged 60 and older, who were up to 18 percent more likely to die on their birthday.

"We find more deaths than expected solely on birthdays, that is neither in the days before nor after the birthdays," says lead author Dr. Vladeta Ajdacic-Gross, an epidemiologist for the Institute of Social and Preventive Medicine at the University of Zurich.

In this large study, which was published in the Annals of Epidemiology, researchers analyzed data from more than 2.4 million Swiss people who died between 1969 and 2008. They tried to determine if there was any relationship between when people died and the cause compared to their birthdays.

"We were surprised that our findings apply to specific causes of death," says Ajdacic-Gross. Both violent causes, such as suicides and falls, as well as strokes and cardiovascular deaths were tied to birthdays. "In addition, older people are distinctly more vulnerable than younger people," he adds.

Men were more likely to have a violent demise on their birthday, as their chances of suicides spiked by nearly 35 percent and their odds of being accident victims rose by almost 29 percent. Deadly falls in men rose by 44 percent on their birthdays, and, interestingly, the number of falls started to increase about four days before the celebration took place.

When it came to natural causes of deaths, women were at greater risk -- almost 22 percent -- of passing away from a stroke on their birthday. For both ladies and gentleman, there was a nearly 19 percent increase in dying from heart-related reasons.

Scientists also unexpectedly found the risk of dying from cancer jumps by 10.8 percent on birthdays. Cancer deaths also seemed to be higher than usual in the days immediately following a birthday -- a trend not seen for any other cause of death. 

But the question you may be asking is: Why? Is birthday partying to blame? Is it a psychological let-down to realize you're one year older -- and not getting any younger?

"We can only speculate on the reasons for the extra deaths on birthdays," points out Ajdacic-Gross. They suspect that birthday-related stress in older people may play a part in the jump in stroke and cardiac deaths.

Other studies have suggested that alcohol may be a reason behind the spike in suicides and perhaps even falls.

The Swiss researchers say their results support the theory of an "anniversary reaction" or "birthday blues," meaning that deaths occurred more frequently on a birthday. They suggest this is a more likely explanation than the "death postponement" hypothesis, or that deaths are less likely to take place on birthdays and people might hang on long enough to reach this yearly milestone -- or to see through certain holidays or special occasions.

Some famous people who have passed away on their birthday include the actress Ingrid Bergman, feminist Betty Friedan, and William Shakespeare. 

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You’re staring at your blank computer screen when dots drift into your line of vision. They resemble specks of dust or perhaps clouds or cobwebs. Don’t panic -- you’re not seeing things. You’re witnessing eye floaters, not tricks of the eye or mind.

“Floaters are a part of the normal aging process,” says Dr. Pravin Dugel, managing partner at Retinal Consultants of Arizona in Phoenix.

Eye floaters are fibers that detach from the eye. A hollow cavity filled with a vitreous jelly, composed of 99 percent water and 1 percent collagen, lies in the center of the eye. This gel helps give eyes their round shape and aids in seeing. As we age, the vitreous liquefies and pieces of it begin to release from the back wall of the eye. The debris floats across the field of vision, causing people to see dots, flies, cobwebs, or clouds.

“You can think of [floaters] as UFOs floating in the eye,” explains Dr. Abdhish R. Bhavsar, director of clinical research at the Retina Center of Minnesota. He explains that unlike UFOs, physicians know what floaters are, but like UFOs they often appear differently based on who sees them. 

While it seems that floaters glide across the front of the eye, they’re actually drifting through the eye. It’s the shadow of the fibers reflecting on the retina that people see. 

Although eye floaters don’t occur in everyone, at least 60 percent of people experience them by age 65, says Dugel. Those who have had cataract surgery or have severe nearsightedness might experience eye floaters earlier in life. People who are nearsighted (or myopic) have longer eyeballs, and the vitreous gel stretches more in myopic eyes than in an eye with either normal vision or farsightedness.

Bhavsar notes that sometimes people experience vitreous detaching, but do not see floaters while others see a large number of floaters while the vitreous shedding is minimal.

Even though both doctors stress that eye floaters should not be cause for concern, they do recommend people go for eye exams if there is a sudden explosion in the number of floaters or flashing lights accompany the dots.

“In some people as that jelly peels off it’s like Velcro peeling off … it pulls on the retina and it causes a tear,” Dugel says.

If the retina tears, ophthalmologists can repair it, using lasers or cyrotherapy, which involves freezing, and can prevent the retina from detaching from the eye. If the retina does dislodge, doctors must perform surgery to repair it.

But for most people, floaters are simply an annoyance. In very rare cases, ophthalmologists perform surgery to remove the vitreous, but for majority of patients, the floaters settle to the bottom of the eye after time and cause no other problem. 

“In the absence of all those other medical conditions, [floaters] are a nuisance and they can affect people in varying [degrees],” says Bhavsar.

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Could fear of the dark be ruining your sleep?

Scientists now say that many sleep problems can be traced to an anxiety that sparks as soon as the lights go down, according to a new study presented at the annual meeting of the Associated Professional Sleep Societies.

The small study found that 50 percent of adults who reported sleep problems also admitted to being scared of the dark - and were also measurably more anxious when the lights were turned off.

“The good news, is that if this is what is going on, it’s very treatable,” said the study’s lead author Colleen Carney, an associate professor at Ryerson University in Toronto. “And it doesn’t take long to treat.”

To see if bad sleep might be phobia driven, Carney and her colleagues rounded up 93 college students and asked them to fill out surveys that included questions about their sleep quality and whether they were afraid of the dark.

Then the researchers ran an intriguing experiment: In the first half of the experiment the volunteers sat in a room with the lights on. In the second half, they sat with the lights off. All the while, the volunteers were wearing headsets that would periodically play a blast of noise.

“Then we watched their reactions in the light and the dark,” Carney said. “In the light they were no different. But in the dark, the poor sleepers were more likely to be startled.”

In other words, compared to the sound sleepers, the insomniacs were more likely to blink and to flinch when they heard the noise in the dark. In fact, the more times they heard the noise, the more anxious and jumpy they got. The good sleepers, in contrast, got used to hearing the noise and eventually stopped reacting to it.

Fear of the dark isn’t something that sleep doctors currently look for, Carney said. So the new research might open new avenues for treatment.

And the good news is that phobias often respond very quickly to treatment with exposure therapy, Carney added. So, just as a therapist can get you used to spiders and snakes by slowly exposing you to them, they’ll also be able get you over your fear of the dark.           

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• Waking a sleepwalker is totally safe -- for them
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First, how big are these bubbles? According to the American anthropologist Edward Hall, whose 1960s research on the topic still stands today, you're actually enveloped by bubbles of four different sizes, each of which applies to a different set of potential interlopers.

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The smallest zone, called "intimate space," extends outward from our bodies 18 inches in every direction, and only family, pets and one's closest friends may enter. A mere acquaintance hanging out in our intimate space gives us the heebie-jeebies. Next in size is the bubble Hall called "personal space," extending from 1.5 feet to 4 feet away. Friends and acquaintances can comfortably occupy this zone, especially during informal conversations, but strangers are strictly forbidden. Extending from 4 to 12 feet away from us is social space, in which people feel comfortable conducting routine social interactions with new acquaintances or total strangers. Beyond that is public space, open to all.

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Those are the average sizes of Americans' personal bubbles, anyway. According to Ralph Adolphs, professor of psychology and neuroscience at the California Institute of Technology, "It is important to keep in mind that personal space of course varies depending on culture and context, and that there are significant individual differences -- so these numbers should just be taken to reflect the average." ( Infographic: A Day in the Life of the Average American )

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As we all know, cultural or individual differences in personal bubble diameters are all too often the cause of discomfort. (Take one step back, foreigners.)

But how do these personal bubbles arise? According to Adolphs, we begin to develop our individual sense of personal space around age 3 or 4, and the sizes of our bubbles cement themselves by adolescence. In research published in the journal Nature in 2009, Adolphs and his colleagues determined that the bubbles are constructed and monitored by the amygdala, the brain region involved in fear.

"The amygdala is activated when you invade people's personal space," he told Life's Little Mysteries. "This probably reflects the strong emotional response when somebody gets too close to us.  We confirmed this in a rare patient with lesions to this brain structure: she felt entirely comfortable no matter how close somebody got to her, and had no apparent personal space."

Furthermore, he said, abnormal development of the amygdala may also explain why people with autism have difficulties maintaining a normal social distance to other people.

There are times when personal space intrusions are simply unavoidable, such as in a crowded subway car. How do we cope? The psychologist Robert Sommer suggested we do it by temporarily dehumanizing those around us, avoiding eye contact and pretending they're inanimate until the moment comes when we spot an escape route. After all, it's not uncomfortable to stand inches from a wall.

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