New research on babies’ brain patterns during sleep adds to the evidence that parents who argue frequently are stressing out their infants. Plenty of research has already indicated that extremely stressful experiences in early life, such as physical abuse or being raised in an institution, affect how the brain processes information. This new study of 20 babies suggests that the more “moderate” stress of having parents who engage in frequent verbal arguments may similarly influence how a baby’s brain develops.
While the babies slept, University of Oregon graduate student Alice Graham used an MRI scanner to gauge their brains’ response to a man’s voice uttering nonsense sentences in various tones. When she and her faculty advisers compared how the babies’ brains processed these different tones, they detected a pattern: when the voice was angry, babies whose parents acknowledged to the researchers that they argued a lot had a greater reaction in areas of the brain that are linked to stress and the regulation of emotion, including the anterior cingulate cortex, caudate, thalamus, and hypothalamus.
Plenty of research has already connected chronic parental strife with negative outcomes for children–including greater levels of anxiety, depression and disruptive behavior. The latest research may suggest mechanisms through which this stress interferes with a child’s developing nervous system. Graham says it will take long-term studies to determine whether “these patterns of brain activity” are what actually cause negative developmental outcomes in children exposed to frequent conflict. Meanwhile, her study is a reminder that babies are not oblivious “blobs”–even when asleep they hear you.