Its not only in newspaper headlines--its even on magazine covers. TIME, U.S. News & World Report and even Scientific American Mind have all run cover stories proclaiming that an incompletely developed brain accounts for the emotional problems and irresponsible behavior of teenagers. The assertion is driven by various studies of brain activity and anatomy in teens. Imaging studies sometimes show, for example, that teens and adults use their brains somewhat differently when performing certain tasks.
As a longtime researcher in psychology and a sometime teacher of courses on research methods and statistics, I have become increasingly concerned about how such studies are being interpreted. Although imaging technology has shed interesting new light on brain activity, it is dangerous to presume that snapshots of activity in certain regions of the brain necessarily provide useful information about the causes of thought, feeling and behavior.
Automatically assuming that the brain causes behavior is problematic because we know that an individuals genes and environmental history--and even his or her own behavior--mold the brain over time. There is clear evidence that any unique features that may exist in the brains of teens--to the limited extent that such features exist--are the result of social influences rather than the cause of teen turmoil. As you will see, a careful look at relevant data shows that the teen brain we read about in the headlines--the immature brain that supposedly causes teen problems--is nothing more than a myth.
The teen brain fits conveniently into a larger myth, namely, that teens are inherently incompetent and irresponsible. Psychologist G. Stanley Hall launched this myth in 1904 with the publication of his landmark two-volume book Adolescence. Hall was misled both by the turmoil of his times and by a popular theory from biology that later proved faulty. He witnessed an exploding industrial revolution and massive immigration that put hundreds of thousands of young people onto the streets of Americas burgeoning cities. Hall never looked beyond those streets in formulating his theories about teens, in part because he believed in "recapitulation"--a theory from biology that asserted that individual development (ontogeny) mimicked evolutionary development (phylogeny). To Hall, adolescence was the necessary and inevitable reenactment of a "savage, pigmoid" stage of human evolution. By the 1930s recapitulation theory was completely discredited in biology, but some psychologists and the general public never got the message. Many still believe, consistent with Halls assertion, that teen turmoil is an inevitable part of human development.
Today teens in the U.S. and some other Westernized nations do display some signs of distress. The peak age for arrest in the U.S. for most crimes has long been 18; for some crimes, such as arson, the peak comes much earlier. On average, American parents and teens tend to be in conflict with one another 20 times a month--an extremely high figure indicative of great pain on both sides. An extensive study conducted in 2004 suggests that 18 is the peak age for depression among people 18 and older in this country. Drug use by teens, both legal and illegal, is clearly a problem here, and suicide is the third leading cause of death among U.S. teens. Prompted by a rash of deadly school shootings over the past decade, many American high schools now resemble prisons, with guards, metal detectors and video monitoring systems, and the high school dropout rate is nearly 50 percent among minorities in large U.S. cities.
But are such problems truly inevitable? If the turmoil-generating "teen brain" were a universal developmental phenomenon, we would presumably find turmoil of this kind around the world. Do we?
In 1991 anthropologist Alice Schlegel of the University of Arizona and Herbert Barry III, a psychologist at the University of Pittsburgh, reviewed research on teens in 186 preindustrial societies. Among the important conclusions they drew about these societies: about 60 percent had no word for "adolescence," teens spent almost all their time with adults, teens showed almost no signs of psychopathology, and antisocial behavior in young males was completely absent in more than half these cultures and extremely mild in cultures in which it did occur.