Credit: Robert Kraft/public domain

Young children whose parents regularly provide warmth and positive reinforcement show more empathy for others and care about following rules, according to a new University of Michigan study examining adoptive families.

Without that parental affection, children may become aggressive and break the rules without feeling guilty as they grow older and enter grade school, U-M researchers say.

The study by U-M psychologists Rebecca Waller, Luke Hyde and colleagues found that, as early as age 3, children can be identified as having callous and emotional behaviors—putting them at higher risk for more severe behavioral problems in the late elementary school years. These kids also showed little guilt about their misbehavior and delayed moral development.

Previous research that has looked at these questions has been limited because only biological parents and their children—not adoptive families—have been studied, and usually at much older ages.

Since and children share genes, previous studies that have found harsh and negative parenting to predict these callous-unemotional behaviors could have just been measuring shared genetic traits—that harsher, more aggressive parents pass those aggressive genes onto their child, the researchers say.

The U-M study is among the first to focus on , as well as children's behaviors during early childhood (ages 2-6) when preventive interventions may be most effective.

Waller and Hyde say that since adoptive parents don't share their genes with their children, their study more conclusively shows that parenting itself is important for preventing the development of callous-unemotional behaviors and early in life.

The researchers studied the behaviors in a sample of children adopted at birth. They observed how parents behaved while helping their 2-year-old kids put away toys. Those adults who offered lower levels of warmth were more likely to have children who exhibited callous-unemotional behavior who later showed more behavior problems five years later in grade school based on teachers' observations.

Waller, a research fellow in U-M's Department of Psychology, said the findings suggest that parenting interventions and treatments to increase their warmth, affection and positive emotional expressions can reduce children's callous-unemotional behavior.

In addition, it can "reduce the likelihood that will show aggression, violence or rule-breaking across the lifespan," said Waller, the study's lead author.

"These studies show that we can focus on preventing many of the most serious types of behavior problems in the preschool period," said Hyde, assistant professor in U-M's Department of Psychology and the study's senior author. "By working with early in a child's life, we may be able to prevent crime and violence that hurts society decades later."

The findings appear in the current issue of Journal of Personality.

More information: "Towards an understanding of the role of the environment in the development of early callous behavior." Journal of Personality. 08/2015; DOI: 10.1111/jopy.12221

Journal information: Journal of Personality