Physhological
The psychological effects of aging are much less established than the physical effects. Even though memory, intelligence, skills, and both the capacity and motivation to learn are widely assumed to decline with age, research into the psychology of aging suggests a much more complicated process. Memory and learning ability, for example, do not decline significantly until very late in life for most people, although the speed with which one recalls or analyzes information may slow somewhat, giving the false impression of mental impairment.
For most elderly people whose lives are stimulating and rich, such mental abilities as motivation to learn, clarity of thought, and problem-solving capacity do not decline significantly until the late eighties. Even Alzheimer's disease is relatively rare in non-institutionalized persons under 75, although it may afflict as many as half of all people over 85. Former president Ronald Reagan is perhaps the most famous example of someone who suffered from Alzheimer's.
Alzheimer's disease is the progressive deterioration of brain cells that is the primary cause of dementia in old ages.
