The field of psychobiology has two major theories for talking about stress and health: the allostatic load model, which grew out of biological and neuroscience approaches to understanding health and disease, and the adaptive calibration model, which developed out of an explicitly evolutionary-developmental framework. Both are based on assumptions that the brain coordinates a distributed and dynamic set of neural circuits that regulate behavior and stress physiology to help the organism adapt to the demands of the environment. Both models support the notion that experiences early in life are embedded into the regulation of stress systems in ways that shape the organism's future responses. These two paradigms differ in their emphasis on whether changes in how stress systems function are viewed as adaptive or maladaptive. The goal of this review is to identify the strengths and weaknesses of each framework and to discuss some implications for future studies and for policy.
Keywords: adaptation; early adversity; stress.