In Infancy, It’s the Extremes of Arousal That Are ‘Sticky’: Naturalistic Data Challenge Purely Homeostatic Approaches to Studying Self-Regulation

Most theoretical models of arousal/regulatory function emphasise the maintenance of homeostasis; consistent with this, most previous research into arousal has concentrated on examining individuals’ recovery following the administration of experimentally administered stressors. Here, we take a different approach: we recorded day-long spontaneous fluctuations in autonomic arousal (indexed via electrocardiogram, heart rate variability and actigraphy) in a cohort of 82 typically developing 12-month-old infants while they were at home and awake. Based on the aforementioned models, we hypothesised that extreme high or low arousal states might be more short-lived than intermediate arousal states. Our results suggested that, contrary to this, both low- and high-arousal states were more persistent than intermediate arousal states. The same pattern was present when the data were viewed over multiple epoch sizes from 1 second to 5 minutes; over 10-15-minute time-scales, high-arousal states were more persistent than low- and intermediate states. One possible explanation for these findings is that extreme arousal states have intrinsically greater hysteresis; another is that, through ‘metastatic’ processes, small initial increases and decreases in arousal can become progressively amplified over time. Rather than exclusively studying recovery, we argue that future research into self regulation during early childhood should instead examine the mechanisms through which some states can be maintained, or even amplified, over time.

This is the peer reviewed version of the following article: Wass, S., Smith, C. G., Clackson, K. and Mirza, F. U., In infancy, it’s the extremes of arousal that are ‘sticky’: Naturalistic data challenge purely homeostatic approaches to studying self‐regulation. Dev. Sci., 24: e13059. https://doi.org/10.1111/desc.13059, which has been published in final form at https://doi.org/10.1111/desc.13059. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.