"I wouldn't stop going anywhere just because I knew somebody was watching," said Olivia.
"They seem very willing, especially with the incentive of the use of a cell phone with unlimited texting and Web use," said Dr. Sarah Wiehe, Pediatric Researcher.
The cell phones are equipped with GPS. Dr. Sarah Wiehe was tracking the girls to see if where they go influences health behaviors like smoking, substance abuse and risky sex.
"It's certainly influenced by family factors and peer factors, but there's most likely also community factors," said Dr. Wiehe.
Maps show where the girls went. In addition, the teens had to tell researchers what they did.
"I did nothing differently," said teen Clare Miller. "Just hung out with my friends and stuff."
Research shows more girls are engaging in behavior puts their health in jeopardy.
In one study, 39 percent of ninth grade girls reported drinking in the past month, compared to 34 percent of boys. One in four teenage girls is infected with an STD.
Suicide rates are also on the rise, between 2003 and 2004 it spiked 76 percent among 10- to 14-year-old girls, and 32 percent among 15- to 19-year-olds.
With this new look into the secret lives of girls, the researchers hope to find ways to encourage them to lead healthier, safer lives.
Researchers say someday they may be able to use cell phones as a means of intervention. For example, researchers could send text messages that would encourage healthy behavior.
Web extra information:
The hidden lives of teenage girls
Tracking their every move
In a pilot study at the Indiana University School of Medicine, researchers used cell phones equipped with a global position system (GPS) to track how 14- to 16-year-old girls spend their free time.
"We didn't know if the technology would work, if the kids would take the cell phones with them or would leave them at home," Sarah Wiehe, M.D., M.P.H., an assistant professor of pediatrics, was quoted as saying. "But they did carry the phones and the GPS data revealed that they were spending more time away from home, school and surrounding areas than anticipated."
Dr. Wiehe and her colleagues hope having the ability to track the teens every move will help them understand their choice of behaviors. "Learning that we were able to track their movement is important because previous studies, which have looked at the effect of environment on teens, have focused only on home, school and surrounding areas."
In January 2008, the Centers for Disease Control and Prevention released a survey that examined the decisions and behaviors of 14,000 9th through 12th graders throughout the United States.
The following are some of the things they found:
- 1 in 4 high school students report using some sort of tobacco.
- 1 in 3 are sexually active.
- 61 percent report that either they or their sexual partner use a condom; a slight decrease from the rate of condom use reported two years prior.
- Only 10 percent of teens use sunscreen regularly.
In January 2009, the CDC reported teen pregnancy is rising for the first time in 15 years, leaving experts wondering whether their prevention methods are failing.
In 1990, the national rate of pregnancies of teen girls was 117 per 1,000 teen girls -- a four-decade high. A steady decline followed but that began to change in the early 2000s.
Today, the highest teen birthrates are in the South and Southwest. Mississippi has the highest with 68.4 births per 1,000 teen girls. Rates are lowest in the Northeast. In New Hampshire, the rate is 18.7 births per 1,000 teen girls. States with the highest rates of decline, such as California and New York, have statewide sex-education standards focused on abstinence and contraception.