If the goals of preventing or ameliorating disease are achieved, thereby permitting individuals to live until their biological time clocks in essence turn off physiological and biochemical processes that sustain life, we might anticipate that life expectancy at birth would increase to perhaps 100 to 110 years (even to 120 years), roughly a three- to four-decade increase for the "developed" world (average life-span currently 76 years) and a four to five decade increase for the "less developed" world (average life-span currently 66 years).
The telomeres appear to serve as the biological clock that determines our maximum physiological life-span. If the enzyme telomerase is added to cells in the test tube, it prevents telomere shortening, so cells stay young and keep dividing, potentially indefinitely.
Super's (1990) life-span
, life-space approach was presented as a life-career rainbow of life roles in a schematic life space.
Throughout the course of history, however, we have never increased the maximum human life-span, estimated at 120 years.
Already, scientists have extended the maximum life-span in two species: to twice normal in the fruit fly (Drosophila) and six times normal in the nematode worm (C.
Dunkle (1996) discussed the interplay of lesbian and gay identity development with career development and suggested that career counselors may find Super's (1990) life-span
approach to career development to be a useful framework.
While most textbooks on life-span
development are organized chronologically, this one is organized topically, with sections on the life-span
perspective, biological processes and physical development, cognitive processes, socioemotional development, social contexts of development, and death, dying, and grieving.
Because many readers may be unfamiliar with the theoretical orientations that I use in this case response, I provide a brief orientation to Baltes and colleagues' (Baltes, 1997; Baltes & Baltes, 1990; Baltes, Lindenberger, & Staudinger, 1998) Selective Optimization With Compensation (SOC) meta-model of human development and Heckhausen and Schulz's (1995) Life-Span Theory of Control.
Heckhausen and Schulz's (1995) Life-Span Theory of Control addresses this omission by providing a target-preference hierarchy that is centered on the construct of control and defines the distinction between primary and secondary control.
Other established theories, such as Super's (1990) life-span
, life-space theory; Gottfredson's (1996) theory of circumscription and compromise; and Krumboltz's (Mitchell & Krumboltz, 1996) social learning theory, bear considerable influences from this worldview.
approach to career development.
From a career-rehabilitation perspective that embraces a life-span
consideration of the interaction of client-specific career development issues and disabling problems, this can be best accomplished by thoroughly assessing the implications for career development caused by a disabling problem (including anticipated or potential degenerative problems caused by a disabling condition) and then determining how potential career-related problems could be alleviated through interventions such as client motivation, transferring acquired skills to occupations within the individual's capabilities, planning for near-term or later career change, retraining, or ergonomic adaptation.