Is 2 much txtng bad 4 u? Staying connected can take a tort--on your thumbs and on your mind.

• Author: Hafner, Katie
• Position: TECHNOLOGY

You probably do it rate at night when your parents re asleep. You do it in restaurants and white crossing the street. You do it in the hallway, in between classes. You do it so much that your thumbs may hurt.

Spurred by unlimited texting plans, American teens sent and received an average of close to 2,300 texts per month in the fourth quarter of 2008, according to the Nielsen Company--more than double the average of a year earlier.

This phenomenon worries physicians and psychologists, who say it is reading to anxiety, distraction in school, falling grades, repetitive-stress injury, and steep deprivation. And texting white driving can be deadly: A recent study found that when drivers texted, their collision rate was 23 times higher than when not texting.

ACHING THUMBS

Sherry Turkle, a psychologist at the Massachusetts Institute of Technology who's been studying texting among teenagers in Boston, says it may be causing a shift in the way they develop.

"Among the jobs of adolescence are to separate from your parents and to find the peace and quiet to become the person you decide you want to be," she says. "Texting hits directly at both those jobs."

Teenagers normally break free from their parents as they approach adulthood. Now, says Turkle, "You have adolescents who are texting their mothers 15 times a day, asking things like, 'Should I get the red shoes or the blue shoes?'"

As for peace and quiet, she says, "If something next to you is vibrating every couple of minutes, it makes it very difficult to be in that state of mind."

Texting may also take a toll on thumbs. Annie Wagner, a 10th-grader in Bethesda, Maryland, can text on her tiny LG phone as fast as she types on a regular keyboard. A few months ago, she noticed painful thumb cramping.

It's too early to tell...