Subjective life expectancy as a correlate of family life expectancy.

Abstract

Subjects were 18 female undergraduates who participated in this study as part of a Life Span Development Course. Ages ranged from 20 to 43 yr. (mean age 29.8 yr. SD: 8.6, Mdn: 27.5 yr.). A questionnaire w3s administered to the subjects asking them for (a) subjective estimates of their projected life span or expectancy, (b) subjective estimates of the 'rough' length of life in their family, and (c) specific ages at death of great-grandparents, grandparents, either parent, and any sibling. The mean subjective life expectancy of this sample was 74.8 yr. (range: 40.0 to 85.0 yr., SD: 12.1 yr.) which was not significantly different from the actual life expectancy of 74.1 yr. for white females born in the United States in 1960 (4) and subjective expectancies were nor correlated with the chronological ages of these subjects. An average age at death of all reported relatives was calculated (M: 66.1, range 43.5 to 81.7, SD: 10.8) and correlated with subjective life expectancies as indicated by a Pearson correlation of .47 (p < .05). These subjective expectancies were strongly correlated (T = .77, p < .001) with the subjectively estimated 'rough' life expectancy (M: 75.0 yr., range 60 to 85 yr., SD: 8.0 yr.). The mean estimate made by these subjects of their life expectancies is consistent with the national average and not correlated with chronological age. However, the correlation of subjective life expectancy with mean life expectancy represents an actuarial improvement over simply using the national average since in fact longevity in families is correlated (2). Further exploration is required to understand how people formulate what we have here called a rough subjective estimate of the typical length of life in your family since, at least for women, this is more highly correlated with expeaations for length of the personal life span than is an average of actual age at dearh in one's family.