You know that babies are delicate and vulnerable. But their vulnerability is not limited their tiny physical form. Research has revealed that a baby’s brain is highly susceptible to its environment—whether negative or positive.
Now another study has found that the development of a baby’s brain is actually affected by what it hears. For instance, angry or disturbed voices, resulting from arguments between parents, have a detrimental effect on the baby’s development.
The study, to be published in Psychological Science, a journal of the Association for Psychological Science, has found that infants respond to angry tone of voice, even when in sleep.
The study, conducted by graduate student Alice Graham with her advisors Phil Fisher and Jennifer Pfeifer of the University of Oregon, reveals that infant brains are highly plastic, giving it scope to develop in response to the environments and encounters they experience. But this plasticity comes at the cost of vulnerability. Severe stress, such as maltreatment or institutionalisation, can have a significant, negative impact on child development, says research.
Graham and colleagues wondered what the impact of more moderate stressors might be. “We were interested in whether a common source of early stress in children’s lives — conflict between parents — is associated with how infants’ brains function,” says Graham.
To answer this question, the researchers decided to take advantage of recent developments in fMRI scanning with infants. Twenty infants, ranging in age from 6 to 12 months, were brought into the lab at their regular bedtime. While they were asleep in the scanner, the infants were presented with nonsense sentences spoken in very angry, mildly angry, happy, and neutral tones of voice by a male adult.
“Even during sleep, infants showed distinct patterns of brain activity depending on the emotional tone of voice we presented,” says Graham.
The researchers found that infants from high conflict homes showed greater reactivity to very angry tone of voice in brain areas linked to stress and emotion regulation.
Previous research with animals has shown that these brain areas play an important role in the impact of early life stress on development — the results of this new study indicates that this might be true for even human babies.
According to Graham and colleagues, these findings show that babies are not oblivious to their parents’ conflicts, and exposure to these conflicts may influence the way babies’ brains process emotion and stress.
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