The research, published in the May/June issue of the journal Child Development, explored the development of the frontal cortex, the area of the brain that lies just behind the eyes and extends to just in front of the ears. This part of the brain controls the ability to think flexibly, control behavior when confronted with challenging situations, and juggle multiple pieces of information at the same time, or multi-task.
To better understand the association between the brain and behavioral development, the researchers had adolescents between ages 9 and 20 complete several behavioral tests designed to measure the functioning of their frontal cortex. One task involved recognizing previously presented faces while a second involved looking at the location of a dot on a computer screen, then, after a delay, indicating where the dot had been. These two tasks assessed "working memory," the ability to use recognition or recall to guide future actions.
A third task required that the youth remember multiple pieces of information in the correct sequence, and sometimes re-order the information in their memory before responding to a question. Finally, the researchers included a task in which participants had to search for hidden items in a manner requiring a high level of multi-tasking and strategic thinking.
The researchers found that the ability to use recall-guided action to remember single pieces of spatial information developed until ages 11 to 12, while the ability to remember multiple units of information developed until ages 13 to 15. However, strategic self-organized thinking, the type that demands a high level of multi-tasking skill, continues to develop until ages 16 to 17.
"When the frontal lobe reaches maturity has been debated among researchers, although it has been speculated that it matures after puberty based on recent imaging data," said lead researcher Monica Luciana, PhD, associate professor of psychology. "Our findings lend behavioral support to that work and indicate that the frontal lobe is continuing to develop until late adolescence in a manner that depends upon the complexity of the task that is being demanded." Put another way, she says, "when we use tasks that would be challenging even for a healthy adult, it becomes apparent that teenagers are still developing the cognitive skills necessary to efficiently manage multiple pieces of information simultaneously."
Those skills improve over time, she says, as the connections between brain cells become more refined, enabling more information to be simultaneously managed.
"These findings have important implications for parents and teachers who might expect too much in the way of strategic or self-organized thinking, especially from older teenagers," she said. "We need to keep their cognitive limitations in mind, especially when adolescents are confronted with demanding situations in the classroom, at home, or in social gatherings."
Summarized from Child Development, Vol. 76, Issue 3, The development of nonverbal working memory and executive control processes in adolescents by Luciana M, Conklin, HM, Hooper, CJ, Yarger, RS (all University of Minnesota). Copyright 2005 The Society for Research in Child Development, Inc. All rights reserved.