What do you get when you mix a bunch of still-developing, college-student brains, emotional immaturity, and an epic amount of alcohol? A fraternity party on a typical American college campus, a lot of people would say.
Many now would add this, too: tragedy.
It's a label that fits the death of 19-year-old Tim Piazza at an alcohol-saturated pledge party in a Penn State frat house. Many people have asked how the events of that night could have gone so far and been witnessed by so many at Beta Theta Pi, and why help was not summoned in time to save Piazza.
But to scientists who study brain development, and how alcohol affects the brain, the events of that night are not surprising.
The brains of adolescents and young adults in their early 20s are not what they will be in a few more years, said Frances Jensen, author of The Teenage Brain and chairwoman of the neurology department at the University of Pennsylvania's Perelman School of Medicine. The differences are crucial when it comes to judgment and impulse control.
"This society until recently has treated adolescents as adults with fewer miles. They're not," Jensen said.
The brain, the body's most complex organ, is the last to fully develop – a process that science now tells us may not be complete until well into a person's 20s. Generally, boys tend to be a couple of years behind girls in this regard, she said.
The development of the brain begins at the base, Jensen said, and progresses to the front of the brain. So the last major brain connections are the prefrontal lobe and the frontal lobe. Those are areas responsible for functions such as decision-making, judgment, impulse control, planning, and empathy.
In other words, the last connections made are responsible for what many think of as common sense: You see someone fall down a flight of stairs, as Piazza did, and you get the person help.
The frontal regions are there, she said, they just haven't fully matured.
Still, this developmental timing is not to say that teenagers can't tell right from wrong, said Ruben Gur, a Penn professor of psychiatry, radiology and neurology and director of the Brain Behavior Laboratory. They just don't think the same way as their elders.
"That's why they might make some decisions that leave adults aghast," Gur said.
Those differences contributed to the U.S. Supreme Court's declaring the death penalty unconstitutional for crimes committed by juveniles, he noted.
Meanwhile, alcohol is known to have drastic effects on the brain, starting with the frontal area that already is challenged in youth.
"Alcohol will basically put it to sleep," said Gur.
Fraternity drinking may be more in the news now, but federal data show that binge-drinking is a widespread problem on campus. About 1,825 college students between the ages of 18 and 24 die each year from alcohol-related unintentional injuries, including car crashes, according to the National Institute of Alcohol Abuse and Alcoholism.
Add to brain development and alcohol, another potent factor likely at play in the Penn State fraternity case: peer pressure.
Research at Temple University has led to provocative insights into how the behavior of teens and young adults can be entirely different when they are around peers.
Jason Chein, an associate professor of psychology and director of Temple's Behavioral Research Imaging Center, and Laurence Steinberg, a Temple psychology professor and expert in teen behavior, found that when adolescents know that peers are watching them, parts of the brain related to reward processing show increased activity. This means the teens are more willing to engage in risky behavior to get those good feelings.
The same appears to be true even of adolescent mice. Chein said they found that young mice given alcohol tend to drink more only when they're around other mice their age. Left alone, they aren't so interested in the stuff. Older mice were unaffected by the presence of their same-age cagemates.
Chein said his work with Steinberg's research has led them to believe that teen behavior can be affected by being in the presence of other teens, even if they don't know each other.
And this goes well beyond drinking. Other research has demonstrated that when teens are together, without adult supervision, they are more likely to get into car accidents and commit crimes — no alcohol needed.
Institutions such as universities and fraternities would do well to consider young people's normal development when considering how to help keep them safer, Chein suggested.
"The science affirms our intuitions that youth, friends, and alcohol make for a particularly potent cocktail when it comes to making judgments," he said, "and this is something we may want our institutions to be more mindful of."