A recent study published in the journal Developmental Science reveals that babies whose mothers engage more sensitively with them during play tend to have heightened brain activity when they encounter happy faces. This response is particularly notable in the dorsolateral prefrontal cortex. The findings shed new light on the link between early caregiving experiences and later emotional and social competencies.
Research consistently shows that early experiences with caregivers are fundamental to brain development and future emotional health. While many studies have focused on the adverse effects of negative caregiving, like neglect or abuse, understanding the impacts of positive maternal behaviors is equally important. The researchers aimed to explore how these positive interactions, specifically maternal sensitivity during infancy, influence the brain’s response to emotional cues.
“We know that harsh parenting experiences can have long-term impacts on children’s brain development. But we wanted to see whether the positive aspects of parenting — like responding sensitively to an infant’s needs — might be related to how the brain functions in the first months of life,” said study author Jessie Stern, a research scientist at the University of Virginia.
For their study, the researchers collected data from a sample of 95 mother-infant pairs at two key developmental stages—when the infants were 5 months and 7 months old. The participants were recruited from a hospital in the mid-Atlantic region of the United States.
Mothers and infants were invited to a laboratory setting where the mothers were asked to engage in a free-play session with their infants. During this session, the mothers interacted with their infants as they normally would, using a set of standardized toys and books provided by the researchers. The interactions were recorded via two cameras, focusing on the infant and the mother, to later analyze the mother’s responsiveness and supportiveness during play.
Maternal sensitivity was evaluated based on the mothers’ responsiveness to their infants’ cues and their ability to support the infants’ activities without undue interference. These behaviors were scored using Ainsworth’s Sensitivity Scales, which are established measures in developmental psychology. Coders trained in these scales watched the video recordings of the free-play sessions and assigned scores reflecting each mother’s sensitivity and cooperation with her infant.
To measure how infants’ brains respond to emotional stimuli, the researchers utilized functional near-infrared spectroscopy (fNIRS). This non-invasive technique measures brain activity by detecting changes in blood flow in the cortex, which reflects neuronal activity. In the fNIRS sessions, infants sat on their caregiver’s lap and viewed a display showing faces with various emotional expressions — happy, angry, and fearful.
The researchers found that infants whose mothers were more sensitive during the free-play sessions displayed more pronounced brain activity in the dorsolateral prefrontal cortex when viewing happy faces. There was no significant interaction with time, meaning that the effect of maternal sensitivity on the brain’s response to happiness was stable across the observed developmental window from 5 to 7 months.
“What we found was that babies whose mothers were more sensitive and responsive during play showed more brain activity in response to happy faces, especially in the dorsolateral prefrontal cortex, a region of the brain involved in self-control and managing emotions,” Stern told PsyPost. “We think that these positive interactions with parents early in life might be important for the healthy development of the social brain.”
Interestingly, the researchers did not find a similar enhancement in brain activity in response to angry or fearful faces associated with maternal sensitivity. This specificity suggests that early caregiving may be particularly influential in shaping how infants respond to positive social cues, which could have implications for the development of social skills and emotional resilience later in life.
“What’s surprising is that these effects were specific to how infants responded to happy faces, but not angry or fearful faces,” Stern said. “What we think is going on is that sensitive care might tune the brain to pick up on positive emotions like happiness, which are socially rewarding.”
By showing that sensitive maternal care is linked to enhanced neural processing of positive emotional stimuli, the study suggests that the early emotional environment can shape the brain’s architecture in ways that support positive social interactions and emotional health. It reinforces the idea that caregiving quality is not just about preventing negative outcomes associated with neglect or adverse experiences but also about actively promoting positive brain development through nurturing interactions.
However, as with all research, the study has its limitations. The sample size, though adequate for observing significant trends, is relatively small and primarily homogeneous, consisting mainly of white, middle-class mothers. This limits the generalizability of the findings across different racial, cultural, and socioeconomic backgrounds. Additionally, the study’s design, while longitudinal, does not establish causality but rather shows an association between maternal behavior and infant brain responses.
“Because we only looked at mothers in our study, it’s really important for future research to understand the role of fathers, grandparents, and other caregivers involved in the child’s life,” Stern added.
The study, “Love on the developing brain: Maternal sensitivity and infants’ neural responses to emotion in the dorsolateral prefrontal cortex,” was authored by Jessica A. Stern, Caroline M. Kelsey, Heath Yancey, and Tobias Grossmann.
