Yes, the "terrible twos" are real. (Case in point: Just this morning, your toddler was screaming for dear life in the middle of a grocery store, or she threw the sandwich she just asked for on the floor because one edge touched a grape.) But what if there's more to the bad behavior?
A team of researchers from the University of Michigan, Penn State University, the University of Oregon and five other universities found that toddlers with a set of traits called callous-unemotional (CU) behaviors are more likely to develop worse antisocial behaviors that can escalate to stealing, aggression and fighting (and usually, incarceration) over the years. The CU behaviors they pinpointed include lying, a lack of empathy and showing little emotion.
“CU behaviors are very distinct from other behavior problems. If we can identify these kids early, we may have a better chance of intervening in a child’s development,” said Jenae Neiderhiser, professor of psychology at Penn State and co-researcher on the study.
But what's the source of these problems? Does it have to do with genes or parenting? In other words, how much of it is nature or nurture?
To answer this, the nationwide study, published in the American Journal of Psychiatry, followed 561 families in an adoption study called Early Growth and Development Study that documented biological mothers' history of severe antisocial behavior as well as the behaviors of the adoptive parents and children.
When the kids were 18 months of age, the researchers observed videotaped play sessions of them and their adoptive moms. They then assessed the children's behavior at 27 months old, which is the youngest a child can be to accurately measure for CU behaviors.
They found that biological mothers' antisocial behavior predicted CU behaviors in their children, even though the biological mothers have limited or no contact with their kids since they were adopted into homes as infants. In other words, nature was at play.
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But they also found that when adoptive moms used high levels of positive reinforcement—whether it's saying "good job" or giving a high-five for helping out—it helped offset the children's CU behaviors, even if they were at high risk of bad behavior.
“Biology is not destiny,” said co-author Luke Hyde, assistant professor of psychology at the University of Michigan and lead author on the study. “Even kids that seem difficult early on can definitely change.”
The researchers will continue to follow this group of kids through early adolescence to see if the behaviors will change after toddlerhood. But the lesson for now? Positive parenting will likely help ensure the tough toddler phase remains just that—a phase.