Marital conflict is a significant source of environmental stress for children, and witnessing such conflict may harm children's stress response systems which, in turn, may affect their mental and intellectual development.
These conclusions come from a new study by researchers at Auburn University and the Catholic University of America. The study appears in the journal Child Development.
Researchers looked at 251 children from a variety of backgrounds who lived in two-parent homes. The children reported on their exposure to marital conflict when they were 8, providing information on the frequency, intensity, and lack of resolution of conflicts between their parents. The study gauged how children's stress response system functioned by measuring respiratory sinus arrhythmia (RSA), an index of activity in the parasympathetic branch of the body's stress response system. RSA has been linked to the ability to regulate attention and emotion. Children's ability to rapidly solve problems and quickly see patterns in new information also was measured at ages 8, 9, and 10.
Children who witnessed more marital conflict at age 8 showed less adaptive RSA reactivity at 9, but this was true only for children who had lower resting RSA. In addition, children with lower baseline RSA whose stress response systems were also less adaptive developed mental and intellectual ability more slowly.
"The findings provide further evidence that stress affects the development of the body's stress response systems that help regulate attention, and that how these systems work is tied to the development of cognitive ability," explains J. Benjamin Hinnant, assistant professor of psychology at the Catholic University of America and one of the researchers.
Explore further: Children's personalities linked to their chemical response to stress