Pulse
Taking Teens to Task
A recent study suggesting teens are less proficient at multitasking struck a nerve with parents and kids.
When University of Minnesota researcher Monica Luciana, Ph.D., and her colleagues decided to evaluate teenagers’ ability to perform multiple tasks requiring memory processing, they never imagined their results would spark an outcry.
Luciana and her co-investigators ran about 200 youths ages 9 to 20 through a battery of tests that tapped into the function of the prefrontal cortex, the part of the brain that allows us to reason at a high level, plan into the future, and remember and organize multiple pieces of information at one time. The researchers tested participants’ ability to remember information and to sort, rearrange, and search for information—tasks that require a higher degree of strategic thinking and the ability to juggle multiple pieces of information at the same time. They found that teens’ ability to do more than one thing at a time continues to develop through late adolescence.
“I called it multitasking, but I think the use of that term got me in a bit of trouble,” says the associate professor of psychology at the University of Minnesota and faculty member at the university’s Center for Neurobehavioral Development. (More on that trouble later.)
Between 2002 and 2004, the researchers tested participants to see if they could recognize faces that had been presented previously and pinpoint the location of a dot on a computer screen after a delay—two tasks that use recognition or recall to guide future actions.
After analyzing cross-sectional data, Luciana concluded that as teenagers get older, they seem to be better able to manage a lot of information simultaneously. “We discovered that up until age 17, the multitasking ability seems to still be developing, but between the ages of 17 and 20, we did not see any differences,” Luciana explains. “What we are inferring through that observation is that by age 17, the multitasking abilities may just be leveling off.” She adds that the physiological causes of these age-related changes are not clear. The results of the study were published in the May/June 2005 issue of Child Development. That’s when the trouble began.
Angry Parents, Angry Teens
When the Society for Research in Child Development, which publishes the journal, issued a press release on the study, the Web site LiveScience.com picked up the news and ran a brief article titled “Why Teens are Lousy at Chores,” which discussed Luciana’s findings. The piece got a “huge number of hits,” Luciana says, and almost immediately, she started receiving e-mails from parents who had read the piece. “I call it hate mail, for lack of a better word,” she says. “These very angry parents were saying, ‘Teens are not lousy at something if they really want to do it,’ and ‘Of course teens multitask; they can watch TV and talk on their cell phones and do their homework all at the same time.’ Essentially, they were implying that my work was not valid.” Online discussion forums also spawned heated words from teens.
Luciana says the issue isn’t as simple as the article implied: “Our argument would be that actually, teenagers who are doing all those things simultaneously are not able to perform as accurately as an adult would. It’s not a question of whether they can or cannot multitask but at what level of proficiency. Had I responded to these criticisms, I would have said that many of the tasks teens typically try to accomplish simultaneously do not necessarily require them to be performed in a highly accurate way.” Luciana says learning to drive is a perfect example of the type of activity that does require precision as well as the ability to process a lot of information and do several things at once.
Research confirms that teens are less proficient drivers than adults. In one study conducted by Ford Motor Company in 2005, researcher Jeff Greenberg and colleagues put teens and adults through a high-tech simulation system to determine the effects of using a cell phone while behind the wheel. Without the distraction of the cell phone, teens and adults had a 3 percent “miss rate” in identifying potentially hazardous events, such as a car quickly changing lanes. When participants used a cell phone, the miss rate rose to 13 percent in adults and to a whopping 53 percent in teens.
Luciana attributes some of the difference to the effect experience has on brain development—a phenomenon she believes should be the focus of future study.
Structure Meets Function
Luciana is not certain exactly how the improvements in multitasking abilities are linked to physiological changes in the prefrontal cortex. “We know a fair bit about how brain structure is changing, and we have ideas about how that maps onto behavioral change, but studies that have tried to specifically connect the two are few. We need to have more studies that look at how structural changes relate to functional changes.”
Luciana hopes that her next study will narrow that gap in understanding. She and her team plan to enroll another 200 participants ages 9 to 20. Over a two-year period that began during the fall of 2004, the researchers will measure the same behavioral indicators as they did the first time, then retest participants. They will also analyze brain images of the youths using diffusion tensor imaging, a fairly new type of magnetic resonance imaging that allows investigators to view the fibers that connect the regions of the brain and evaluate how well those fibers are organized.
Luciana says she and her colleagues are most interested in the prefrontal cortex’s white matter because it connects with many other regions of the brain to promote high-level information processing. “What we are hypothesizing is that white matter is becoming more organized in adolescence and that it’s helping to support some of these behavioral changes,” she says. “Our data are preliminary at this point, but we are seeing the same pattern of multitasking ability as in the first study. Hopefully, we will be able to link this pattern with structural brain changes.”—Jeanne Mettner