Parental neural responsivity to infants’ visual attention: how mature brains influence immature brains during social interaction.

The neuroimaging techniques that we currently have work best for studying brain activity when one person is on their own, looking at a computer screen. But, as I’ve argued here, this is useful for understanding some, but not all, of the ways in which we actually pay attention in the real world. In particular, current neuroimaging techniques are less well suited for helping us understand the dynamic influences of social context. This is particularly important, of course, for early development – given that infants spend the majority of their early lives interacting with caregivers.

We know that, when one social partner pays attention to an object, this increases the attention that another social partner pays to that object. But how are these types of short-term, transient influences on attention substantiated in the brain? In our new paper, which is out now in PLoS Biology, we looked at this...

We asked parents and the infants to engage in free, tabletop play with toys in two settings. In the first, Joint Play, the parent and child played together (the left picture, above); in the second, Solo Play, they played in parallel with two identical sets of toys (the right picture). While they were doing this we recorded 32-channel EEG from both infant and parent concurrently.

We video coded at 30 fps the exact times of the infants’ and parents’ looks to and away from the object that they were playing with, and we epoched and FFT’ed our EEG data to give us a continuous estimate of the changing power at different frequencies in the brain. And then we used cross-correlations to look at the continuous relationship between look duration and neural activity. Using this technique, which is basically a low-tech way of looking at Granger-causal associations, we could look at whether changes in brain activity tend on average to anticipate, or to follow on from, shifts in visual attention. And in terms of which aspect of brain activity we were interested in, we were most interested in theta activity (3-6Hz in infants), as a number of papers (eg, eg, eg) have suggested that theta is involved in anticipatory and sustained attention in infants.

We found, that, when infants were engaged in Solo Play, the associations were strongest when we compared brain activity at one moment in time to looking behaviour 750ms after that moment. In other words, the infant’s theta brain activity slightly anticipated their looking behaviour. When the baby was engaged in Joint Play with a parent, however, this endogenous relationship between the infant’s brain activity and their own attention patterns was lower.

This was exactly what we’d expected to find based on this paper (see also here), where we argued that, during shared play, parents control their infants’ visual attention, and sustain it using exogenous gaze cues. So it makes sense, to us that infants’ own endogenous brain activity is less predictive of their visual attention during Joint Play than during Solo Play.

When we looked at the cross-dyad relationship – looking at how the parent’s brain activity related to the infant’s patterns of attention – we also found something else interesting. We found reactive increases in parental theta activity that were time-locked to the infant’s attention patterns – independent of the parent’s own attention patterns. This type of responsive brain activity was, we argued, perhaps similar to previous findings that provided evidence for common activation elicited when experiencing emotions in oneself, and when perceiving the same feelings in others.

There are, of course, plenty more questions to look at from here. First, what about the findings suggesting that the children of parents who show increased responsivity over shorter time-frames develop superior endogenous attention control over long time-frames? If parents exogenously control their infant’s attention during shared play, then how does this lead to increased endogenous attention control infants later on? Second, what about the recent findings that emphasise ‘active learner’ approaches to early learning – suggesting that infants’ own endogenous contributions to their own learning are much greater than previously appreciated? Of course, it’s not a question that infants are either active or passive learners – but there certainly is a lot more to look at here. Third, is this type of responsive brain activity unique to, or even stronger in, parent-child dyads than in strangers – and stronger in some parent-child dyads than others...? Hopefully we’ll be able to look at some of these questions in more detail over the next few years...!