Ageing or aging is the process of getting older. This article focuses the social, cultural, and economic effects of ageing. The biology of ageing is treated in detail in senescence. Ageing is an important part of all human societies reflecting the biological changes that occur, but also reflecting cultural and societal conventions. Age is usually, but wholly arbitrarily, measured in years and a person's birthday is often an important event.
There is often considerable social pressure in modern society to hide signs of ageing, especially among women. This may involve dyeing hair, elaborate make-up, or even cosmetic surgery. Among the young however there is often a desire to seem older to gain more responsibility and respect.
The issues of an ageing population in which the average age of a society is increasing is an important issue in many nations of the world. The societal effects of age are great. Young people tend to commit most crimes, they are more likely to push for political and social change, to adopt new technologies, and to need education. Older people are more likely to be conservative both politically and socially; and in their daily lives, rather than education, health care and pensions are essential to them. Older people are also far more likely to vote and thus have comparatively more political influence.
Senescence: the biology of ageing
Main article: Senescence
In biology, senescence is the state or process of aging. Cellular senescence is a phenomena where isolated cells demonstrate a limited ability to divide in culture. Organismal senescence is the aging of organisms.
Organismal aging is generally characterized by the declining ability to respond to stress, increasing homeostatic imbalance and increased risk of disease. Because of this, death is the ultimate consequence of aging. Some researchers are treating ageing as a "disease" in gerontology (specifically biogerontologists), although this view is controversial.
Dividing the lifespan
A human life is often arbitrarily divided into various ages. Because biological changes are slow moving and vary from person to person arbitrary dates are usually set to mark periods of human life. Legally Adulthood begins at the age of eighteen or nineteen, while old age begins often at age sixty-five.
See also Seven ages of man for an older system of dividing the human life.
Age and the law
There are many legal limits that are attached to age such as voting age, drinking age, the age where one can hold public office, mandatory retirement age.
In jurisprudence, the defense of infancy is a form of defense by which a defendant argues that, at the time a law was broken, they were not liable for their actions, and thus should not be held liable for a crime. Many courts recognize that defendants, which are considered to be juveniles, may avoid criminal prosecution on account of their age.
Economics and marketing of ageing
The economics of ageing are also of great import. Children and teenagers have little money of their own, but most of it is available for buying consumer goods. They also have considerable impact on how their parents spent their money.
Young adults are an even more valuable cohort. They often have jobs with few responsibilities such as a mortgage or children. They do not yet have set buying habits and are more open to new products.
The young are thus the central target of marketers. Television is programmed to attract the 15 to 35 years olds. Movies are also built around appealing to the young.
The middle aged and the old are less likely to buy things and are traditionally viewed as being set in their buying habits and not nearly as open to marketing. Older people tend to be much wealthier and to save a much higher percentage of their income.
Some tax systems attempt to address these differences in age spending habits such as the concept of a lifetime income tax.
Global aging trends
There have been small changes in age distribution between 1990 and 2000. The percent of population that is older increased slightly between 1990 and 2000 from 9% to almost 10%. The increase was larger within more developed countries, from 17.7% to 19.4%. The percent of population that is older is almost three times as high in more developed countries (19.4%) as it is in less developed countries (7.7%).
- Global Social Change Reports (http://gsociology.icaap.org/reports.html) One report describes global trends in aging.
- SAGE Crossroads (http://www.sagecrossroads.net) online forum for emerging issues of human aging
- Alliance for Aging Research (http://www.agingresearch.org/)
- senescence.info (http://www.senescence.info/)
- Dr Aubrey de Grey: 'We will be able to live to 1,000' (http://news.bbc.co.uk/1/hi/uk/4003063.stm)