November 15, 2013
Using the high-tech tools of a new field called neurogenetics and a few simple questions for parents, a University of Michigan researcher is beginning to understand which boys are simply being boys and which may be headed for trouble.
"When young children lie or cheat or steal, parents naturally wonder if they'll grow out of it," said Luke Hyde, a U-M psychologist who is studying the development and treatment of antisocial behavior.
Hyde, a faculty associate at the Institute for Social Research and assistant professor of psychology, is an expert on how genes, experience and the brain work together to heighten or reduce the risk that normal childhood transgressions will develop into full-blown conduct disorders in adolescence and early adulthood.
"The lifetime prevalence of conduct disorder is around 10 percent, and even higher in males and low-income populations," Hyde said. "The total cost to society is enormous, since these behaviors are often chronic, lasting through adulthood."
With colleagues at U-M, Duke University, the University of Pittsburgh and other institutions, Hyde has been exploring the role of the environment and biology as they interact over time to shape behavior.
In particular, he is using techniques of a new field called neurogenetics, which combines genetics, neuroscience and psychology, to learn how genes and neural processes interact with harsh environments, including dangerous neighborhoods and harsh parents, and with a child's own levels of empathy and personality traits, to increase the risk of antisocial behavior.
In one recent study, for example, Hyde and colleagues studied subjects with over-reactive amygdalae. The amygdala is an almond-shaped part of the brain's primitive limbic system involved in processing fear and other visceral emotions. It has been associated with impulsive, aggressive behavior, as well as anxiety disorders and depression.
"Previous research suggests that the amygdala becomes over-reactive probably as a result of both genetics and experience," Hyde said. "And once the amygdala is over-reactive, people tend to behave in an anxious, over-reactive way to anything they see as a potential threat.
"Our study found that this tendency is moderated by a person's environment, including the social support they get. If they're not getting support from family, friends, neighbors or professionals, then the link between the amygdala and anxious behavior is much stronger."
In another study, Hyde and colleagues showed that kids who are impulsive are only at higher risk of engaging in antisocial behavior if they live in dangerous neighborhoods.
He also identified specific items within childhood behavior checklists that can be used as early as age 3 to identify kids who will likely have worse trajectories for antisocial behavior compared to other children who have similar behavior problems, such as throwing tantrums.
These items assess observable behaviors that include whether the child is cruel to animals, doesn't seem to feel guilty after misbehaving, is sneaky, lies, is selfish or won't share, and won't change his or her behavior as a result of punishment.
"The results of this test aren't really meaningful until age 3," Hyde said. "Before that, many of these behaviors are fairly common and don't predict anything. But after age 3, if children are still behaving in these ways, their behavior is more likely to escalate in the following years rather than improve."
There is good news, though. Kids who scored high on this test benefitted just as much as other kids from interventions, according to Hyde. These interventions include training parents to spend more positive time with their kids, use time-outs instead of physical punishments and reward good behavior by giving out stickers.
"Parents need to know that intervention works, especially if it's done early," Hyde said. "They need to go for help if they see signs of trouble. Clinical psychologists, among other professionals, have empirically supported treatments that are quite effective for children, especially in this age period."