Specifying the timescale of early life unpredictability helps explain the development of internalising and externalising behaviours

Abstract

Early life unpredictability is associated with both physical and mental health outcomes throughout the life course. Here, we classified adverse experiences based on the timescale on which they are likely to introduce variability in children’s environments: variations unfolding over short time scales (e.g., hours, days, weeks) and labelled Stochasticity vs variations unfolding over longer time scales (e.g., months, years) and labelled Volatility and explored how they contribute to the development of problem behaviours. Results indicate that externalising behaviours at age 9 and 15 and internalising behaviours at age 15 were better accounted for by models that separated Stochasticity and Volatility measured at ages 3 to 5. Both externalising and internalising behaviours were specifically associated with Volatility, with larger effects for externalising behaviours. These findings are interpreted in light of evolutionary-developmental models of psychopathology and reinforcement learning models of learning under uncertainty.

A framework for studying environmental statistics in developmental science.

“…Many studies explore the challenges that environmental change poses to developing individuals. To identify these challenges researchers study how environmental change shapes such outcomes as health and cognition (Farkas et al, 2024). Indeed, predictable and unpredictable changes may produce different developmental outcomes (Baram et al, 2012; Gee, 2021; Ugarte & Hastings, 2023; Werchan et al, 2022).…”