Economic hardship is known to shape children’s self-regulation, yet little is understood about how fluctuations in hardship unfold over time and whether different patterns of unpredictability carry unique developmental consequences. Using a socioeconomically diverse sample, we tracked families’ subjective economic hardship across 15–36 monthly assessments and applied an environmental statistics framework to quantify four indices of unpredictability: changepoints in mean, changepoints in variance, coefficient of variation, and noise. PCA identified two distinct forms of economic unpredictability: one marked by frequent, unpredictable hardship, and another by infrequent but abrupt hardship. Economic unpredictability was disproportionately experienced by racially minoritized and lower-income families in our sample, reinforcing structural inequities in economic resources. Relations between these indices and caregiver-reported measures of family routines and day-to-day unpredictability were weak, suggesting wide heterogeneity in the ways families adapt to economic unpredictability. Leveraging propensity score methods, we isolated the effects of unpredictability from hardship severity, finding that both were associated with greater self-regulation challenges in early childhood, with the strongest effects for hardship severity. These findings underscore the importance of capturing economic hardship as a dynamic and multidimensional experience, with implications for policy efforts aimed at promoting stability in families’ access to resources over time.

Building on Ellis et al.’s theorization for potent dimensions of environmental adversity, the present work sought to evaluate how environmental harshness and unpredictability might function directly and in interaction with child sensory processing sensitivity (SPS) to shape the development of child socioemotional functioning. Participants were 235 young children (Mage = 2.97 at the first measurement occasion) and their parents, who were followed for two consecutive annual measurement occasions. Child SPS was measured through behavioral observation across multiple tasks within the laboratory setting. Greater environmental unpredictability was significantly associated with the development of children’s externalizing problems over a year only for children with high SPS. Follow-up analyses indicated that the unpredictability-x-SPS interaction was consistent with differential susceptibility, such that high SPS children showed greater increases in externalizing problems under high unpredictability, but also lower increases/greater decreases in externalizing problems under low unpredictability. Such association did not apply to children with low SPS.