One of the leading models of successful aging is the life-span model of Selective Optimization with Compensation model (SOC-model) developed by P. Baltes and M. Baltes (1990), which states that aging may be best characterized as a heterogeneous process with many different pathways and (successful) outcomes. The SOC-model's authors (Baltes & Baltes,
1990) were therefore among the first to describe the processes of successful aging instead of solely defining the end points.
From the viewpoint of the SOC-model, people select life domains that are important to them, optimize the resources and aids that facilitate success in these domains, and compensate for losses in these domains in order to adapt to biological, psychological, and socio-economic changes throughout their lives and to create an environment for lifelong successful development. Since stressors, such as declining health, may multiply whereas resources decrease in later life, selection, optimization and compensation processes become increasingly important during aging to maintain a positive balance between gains and losses