Childhood socioeconomic status and the pace of structural neurodevelopment: accelerated, delayed, or simply different?

Abstract

Socioeconomic status (SES) is associated with children's brain and behavioral development. Several theories propose that early experiences of adversity or low SES can alter the pace of neurodevelopment during childhood and adolescence. These theories make contrasting predictions about whether adverse experiences and low SES are associated with accelerated or delayed neurodevelopment. We contextualize these predictions within the context of normative development of cortical and subcortical structure and review existing evidence on SES and structural brain development to adjudicate between competing hypotheses. Although none of these theories are fully consistent with observed SES-related differences in brain development, existing evidence suggests that low SES is associated with brain structure trajectories more consistent with a delayed or simply different developmental pattern than an acceleration in neurodevelopment.

Keywords: acceleration; adversity; delay; poverty; socioeconomic status; structural brain development.

Figure 1:. SES and the pace of neurodevelopment: theoretical predictions and empirical observations.

Expected trajectories of cortical thickness from infancy to late adolescence based on models of accelerated (A) and delayed (B) brain development Solid and dashed lines represent trajectories for high and low-SES youth, respectively. Panel C depicts the patterns observed in existing longitudinal studies. These patterns suggest that low-SES children have consistently lower cortical thickness, volume, surface area, and subcortical volume as well as slower rates of change during both growth and decline. Figures depict the starting point for low- and high-SES infants to coincide as evidence on SES-related differences in brain volume at birth is limited. Blue and green lines represent average trajectories for cortical thickness and subcortical volume—specifically amygdala and hippocampus, respectively.