A parent and child participating in the study (Image credit: Kaili Clackson, CC-BY) A parent and child participating in the study (Image credit: Kaili Clackson, CC-BY)

Humans are inherently social. This is particularly important in early development, as young infants spend the majority of their lives interacting with caregivers. However, almost everything that we know about how the brain subserves early attention and learning comes from studies that examined brain function in one individual at a time (largely because it is easier to conduct experiments this way). So, we set out to examine how attention is dynamically shared between a parent and child engaged in social interaction.

Our study was novel because of how the data was recorded. Current neuroimaging techniques work best or studying brain activity with one person, on their own, ideally focusing on one object at a time (like a computer screen). We used a technique called electroencephalography (EEG) to record electrical activity in infants’ and parents’ brains at the same, while they played with toys in two settings. In the first, Joint Play, the parent and child played together; in the second, Solo Play, they played separately, in parallel, with two identical sets of toys. The exact times of the infants’ and parents’ looks to and away from the object that they were playing with were also recorded.

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In terms of brain activity we expected to be involved, we were most interested in theta activity (3-6Hz in infants), as a number of papers have suggested that theta is involved in anticipatory and sustained attention in infants; theta band activity increases in infants during periods of anticipatory and sustained attention and theta activity also increases in infants in social compared to nonsocial settings and in naturalistic settings. Therefore, it was determined that this would be a suitable measure of specifically social attention.

We especially wanted to look at whether changes in brain activity tended on average to anticipate, or to follow on from, shifts in attention. This was important as it gives us a clue as to whether the shift in attention was prompted by the infants’ own internal thought processes, or whether the shift in attention was prompted by something else (most likely the parent). When infants were engaged in solo play, the brain activity at one moment in time was strongly linked to looking behavior 750ms after that moment. In other words, the infant’s theta brain activity slightly anticipated their looking behavior. This was what we had expected to find based on previous research.

When the baby was engaged in joint play with a parent, however, this relationship between the infant’s brain activity and their own attention patterns was lower. So, the infants’ own brain activity is less predictive of their visual attention during Joint Play than during Solo Play. This indicates, most likely, that the shift in attention during joint play was prompted by the parent, with the baby having less control of their own behavior. (This is thought to be because parents “scaffold” their child’s attention during joint play, effectively lowering the child’s need to control their own attention.)

This prompted us to examine how parents’ brainwaves varied alongside their children. We found that the parents were showing similar fluctuations in theta power – and that these were linked to their infants’ attention patterns and not their own. It is almost as if the parents’ brain activity becomes “synced” to their child during joint play. Furthermore, instances in which parents’ brainwaves tracked their children’s brainwaves were associated with longer sustained attention by infants. This suggests that parents are neurally responsive to their infants during social play, and that, when the parent is more neurally responsive, the infant is more attentive.

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However, we still don’t know whether some parents are more responsive to their babies than others, and we don’t know why this might be the case. This study also only used mothers as the “adult” in each pair, so we don’t know whether mums and dads may be different in how they respond neurally to their babies.

This is the first study, to our knowledge, to demonstrate associations between infants’ attentiveness and variability in parents’ attention-related brainwave patterns; it also demonstrated how these two factors varied on a small, moment-to-moment, scale. We look forward to investigating further on how, exactly, this type of neural responsiveness by parents may help young children to learn.