New research examines what goes on in the brains of mothers when they hear their infant crying. The findings may help to identify inadequate caregiving behavior.
A team led by researchers at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) set out to explore the brain patterns involved in maternal responses to the sound of infants crying.
Marc Bornstein, Ph.D. — chief of the NICHD's Section on Child and Family Research — led the research, and the findings were published in the journal Proceedings of the National Academy of Sciences.
According to the new study, hearing the cry of an infant activates brain areas associated with movement and speech, and certain brain and behavioral patterns are universal across many cultures.
Behavior consistent with brain activity
In order to examine maternal response, the researchers analyzed the behavior of 684 mothers across 11 countries — "Argentina, Belgium, Brazil, Cameroon, France, Israel, Italy, Japan, Kenya, South Korea, and the United States" — representing a wide cultural variety.
In the first part of the study, they recorded and analyzed how mothers and infants interacted for 1 hour. During this time, the team looked for signs of affection, distraction, nurturing, and talking.
Examples of nurturing behavior included feeding the baby and changing their diaper. Additionally, the team looked at how often the mothers picked up the babies and held them.
Speaking to Medical News Today about the findings, Dr. Bornstein said:
"Of [five] common positive responses, two were regularly engaged in quickly [...] and preferentially: pick up and hold and talk to."
Dr. Borstein explained that typically, mothers picked up, held, and talked to their children within 5 seconds of hearing them cry.
Mothers also engaged in several other behaviors "at times," said the researcher, but it was evident that these two actions were "preferred, rapid, and robust."
Moreover, the findings could be generalized cross-culturally. With this knowledge, Dr. Bornstein said, "We hypothesized that certain neural mechanisms might be [at] play."
So, "In the second [...] part of the study, we asked  mothers of [three] different cultures [...] to [lie] in the MRI scanner and listen to infant cries — their own infant's cry or standard cries — versus other sounds and noise," he continued.
The studies "revealed enhanced activity in concordant brain territories linked to the intention to move and to speak, to process auditory stimulation, and to caregive."
These brain regions were the "supplementary motor area, inferior frontal regions, superior temporal regions, midbrain, and striatum."
Strengths and limitations of the study
Speaking to MNT about the findings, Dr. Bornstein said, "[We] were surprised [...] by the relative consistency of the patterns of behavioral responses of mothers [...] around the globe."
He pointed out further strengths of the research, saying, "We also studied brains of nearly 100 mothers (and non-mothers) in three [countries] in the MRI scanner and also found consistent patterns of brain responses."
However, Dr. Bornstein also highlighted some limitations to his study: "For the behavioral part we studied participants [from] 11 cultures," he said, "but these participants were not representative of their whole nations, of course, and for the brain part we studied participants in [three] cultures, and the same holds true."
"Also," he continued, "we did not measure the brains of the same mothers for whom we recorded behaviors (or vice versa), and so we are assuming [...] that these brain-behavior associations hold."
"Finally," concluded Dr. Bornstein, "this was not an experiment, but the coordination of [two] sets of observations: about behavior and brain."
In the future, the scientists plan to continue to analyze "an abundance of cross-cultural and fMRI [functional MRI] data."