My brain made me do it

At the moment, most of what we know about how the developing brain functions during social interaction comes from studies that look at individual humans in isolation. This is paradoxical of course, and it has come about purely for practical reasons: most neuroimaging setups can only record from one brain at once, and so almost everything that we know comes from studies that presented social stimuli (such as pictures of faces) to infants while they were  passively  viewing them on a screen. We already know from other studies that there are a number of differences between  which brain regions are active during social interaction, that illustrate the importance of studying social interaction in ecologically valid contexts. For example, mentalizing and reward networks show markedly different patterns of activity during live interaction, compared to when passively viewing equivalent social stimuli on a screen . But one thing that we don't know very much about is how ...

In adult psychology we are quite used to the idea of self-reinforcing mood states: how processes such as rumination or attention biases  can act both as a consequence, and cause, of elevated arousal - leading to small initial fluctuations in arousal becoming amplified over time. Weirdly, though - and despite the usefulness of this idea for parents - this idea of self-reinforcing mood states hasn't made its way yet into child psychology . It's long been an aim of mine to take some of the computational processes used, for example, in modelling epilepsy (such as the image above, which is from this paper ) to look at this. I've just managed to finish off a paper  which takes a step in that direction. We recorded day-long spontaneous fluctuations in autonomic activity (heart rate, heart rate variability and actigraphy) in 12-month-old infants. We just measured, quite simply, the relationship between a child's overall level of arousal and how stable their arousal ...