Major life decisions such as marriage, divorce, abortion, having a child and attending university may be subconsciously influenced by how long people believe they will live, according to a Queen's University study.

"Life expectancy might be driving all of these major decisions," says Daniel Krupp, a post doctoral fellow in the Queen's math department who has a background in psychology and biology.

The longer someone expects to live, the more time they will invest in education. If life expectancy is short, someone may decide to get married and have children sooner, or stick with the partner they are currently with rather than seek a divorce.

It is impossible to know how long someone is going to live, but there are many life expectancy cues not consciously processed, affecting how many more years people expect to live. How healthy are they? Do they have a risky job? Are their grandparents still alive? Is there a history of disease in the family?

A branch of evolutionary theory known as life history theory predicts life expectancy to influence major life decisions in humans, as it does in the lives of other animals. Dr. Krupp's findings based on population data from Statistics Canada help to confirm this.

The study just been published online by the Archives of Sexual Behaviour.