Abstract
The brain's remarkable plasticity during early development makes it highly responsive to environmental input, with early experiences having lasting effects on functioning and development. Both adversity and variations in normative caregiving experiences influence developmental trajectories. Accurately assessing these diverse experiences is crucial for understanding their role in shaping brain development, yet current measurement approaches face significant challenges that limit our ability to capture the complex, multidimensional nature of children's environmental exposures. This review examines seven key challenges in measuring early experiences: (1) Conflation of exposure and response, (2) Oversimplification of complex experiences, (3) Informant bias and reliability issues, (4) Biomarker overinterpretation and inferential leaps, (5) Limited ecological validity, (6) Genetic confounding, and (7) Limited generalizability across cultures and communities. We discuss how these limitations constrain our understanding of how diverse early experiences shape brain development and propose evidence-based approaches to address each challenge. Emerging frameworks that distinguish between different dimensions of adversity, technological advances in passive monitoring, and genetically-informed research designs offer promising paths forward. By advancing precise, high-dimensional approaches to measuring early experiences, researchers can improve understanding of fundamental neurodevelopmental processes while addressing questions of practical significance in education, mental health, and social policy.