Parents who physically abuse their children appear to have a physiological response that subsequently triggers more harsh parenting when they attempt parenting in warm, positive ways, according to new research.

Reporting in the quarterly journal Couple and Family Psychology: Research and Practice, a five-member team, led by Elizabeth A. Skowron, a professor in the Department of Counseling Psychology and Human Services in the University of Oregon College of Education, documented connections between the nervous system's ability to calm heart rate -- via electrocardiogram (ECG) measures of parasympathetic activation -- and the type of parenting mothers displayed during a laboratory interaction with their preschool child.

Studies of child maltreatment have consistently found that parents who physically abuse their children tend to parent in more hostile, critical and controlling ways. Skowron's team appears to have found evidence of a physiological basis for patterns of aversive parenting -- the use of hostile actions such as grabbing an arm or hand or using negative verbal cues in guiding a child's behavior -- in a sample of families involved with Child Protective Services.

For the experiment, mothers and children were monitored to record changes in heart rate while playing together in the lab. Parenting behavior was scored to capture positive parenting and strict, hostile control using a standard coding system.

What emerged, Skowron said, were clear distinctions between abusive, neglectful and non-maltreating mothers in their physiological responses during parenting. When abusive mothers were more warm and nurturing, they began to experience more difficulty regulating their heart rate and staying calm. This physiological-based stress response then led the abusive mothers to become more hostile and controlling toward their child a short time later in the interaction.

The same was not the case for mothers who had been previously identified as being physically neglectful or for mothers with no history of neglectful or abusive parenting.

Participants in the National Institutes of Health-funded study were 141 mothers -- 94 percent Caucasian with a high school degree or less and incomes at or below $30,000 -- and their children, ranged in age from 3 to 5 years old. The research focuses on tracking the effects of physiology on parenting in real time.

"Abusive mothers who try to warmly support their child when the child faced a moderate challenge displayed a physiological response that suggested they're stressed, on alert and preparing to defend against a threat of some kind," said Skowron, a researcher at the Child and Family Center/Prevention Science Institute at the UO. "This kind of physiological response then led to a shift in an abusive mother becoming more hostile, strict, and controlling ways with her young child, regardless of how her child was behaving."

The findings, she added, suggest that when physically abusive mothers experience being a nurturing parent they find it to be hard work. "It appears to quickly wear them out, perhaps because it challenges them in ways that lower-risk mothers don't experience," she said. "An abusive mother appears caught: When she does a good job with her child, it costs her physiologically, and it negatively affects her because it leads to more aversive parenting."

The team's findings help to explain why abusive parenting is so resistant to most interventions, Skowron said. "Most parents who struggle with child maltreatment really love their children and want help improving their parenting skills. Our findings suggest that many are experiencing a biological response during parenting that actively interferes with their efforts to parent in warm and nurturing ways."

The next step, she said, is exploring how to translate the new discovery into interventions specifically designed for parents struggling with child abusive. "We have to figure out how to help these high-risk parents calm themselves down more effectively and enjoy the experience of supporting their children in warm, positive ways. First, she noted, it will be important for other researchers to replicate the findings.

"Researchers at the University of Oregon continue to yield critical insights that result in more effective prevention strategies," said Kimberly Andrews Espy, vice president for research and innovation and dean of the UO Graduate School. "This research by Dr. Skowron revealing a potential neurobiological trigger involved in abusive parenting may lead to new interventions that could help to improve the lives of children."