mately must been seen as a function of society, not of a physical or medical process.

As described in Chapter 3, disability is not inherent in an individual but is, rather, a relational concept—a function of the interaction of the person with the social and physical environments. The amount of disability that a person experiences depends on both the existence of a potentially disabling condition (or limitation) and the environment in which the person lives. For any given limitation (i.e., potential disability), the amount of actual disability experienced by a person will depend on the nature of the environment, that is, whether the environment is positive and enabling (and serves to compensate for the condition, ameliorate the limitation, or facilitate one's functional activities) or negative and disabling (and serves to worsen the condition, enhance the limitation, or restrict one's functional activities).

Human competencies interact with the environment in a dynamic reciprocal relationship that shapes performance. When functional limitations exist, social participation is possible only when environmental support is present. If there is no environmental support, the distance between what the person can do and what the environment affords creates a barrier that limits social participation.

The physical and social environments comprise factors external to the individual, including family, institutions, community, geography, and the political climate. Added to this conceptualization of environment is one's intrapersonal or psychological environment, which includes internal states, beliefs, cognition, expectancies and other mental states. Thus, environmental factors must be seen to include the natural environment, the built environment, culture, the economic system, the political system, and psychological factors. The categories and factors in these tables are not exhaustive and are provided as examples of the very broad and pervasive influence of a person's environment. This chapter illustrates how each of these environmental factors can have an impact on disability.

Impact of the Physical Environment on the Disabling Process

As discussed in Chapter 3, the environmental mat may be conceived of as having two major parts: the physical environment and the social and psychological environments. The physical environment may be further subdivided conceptually into the natural environment and the built environment. Both affect the extent to which a disabling conditions will be experienced by the person as a disability.

Three types of attributes of the physical environment need to be in place to support human performance (Corcoran and Gitlin, 1997). The



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement