PARIS, April 26 -- At what age do we reach "old age"? This question was explored in a study of over 14,000 people in Germany. The results suggest that perceptions of old age have evolved over the generations, with younger people tending to perceive the onset of old age as starting later than their elders.

Trying to guess the age of a coworker, an acquaintance or a distant family member can be a minefield, because age is often a sensitive subject. All the more so since, from one person to the next, the criteria for categorising someone as "old" or "elderly" vary greatly depending on the age of the person making the judgment.

What does it even really mean to be "old"?

Wouldn't it be wiser to adhere to the old adage that age is a state of...