Generation X (Gen-X) has loosely been defined as a particular demographic born in the United States between the years of 1965 and 1982. This group shares many common characteristics and traits, largely defined by their experiences. These criteria for definition are NOT defined in stone, however. The characteristics, traits, beliefs, values, personae, etc. of this group can vary in degree, as well as be held by others that may have been born before or after this time period and outside the geography.
Influences on adopting these characteristics could include having siblings, family members, or friends in a close relationship. Additionally, those persons that were born in a "cusp" of about five years before or after 1965 to 1982 may adopt similar ideals in varying strength, particularly if they have siblings that were born during this time or "hung out" with older or younger friends and family that had been born during this time. Thus, based on many well-established principles of psychology and sociology, the influence of family, friends, and peers can have a pronounced effect on your own beliefs, behaviors, and character.
Some of the best material to explain the differences of values, beliefs, and lifestyle can be seen in the classic lectures of Dr. Morris Massey. I was fortunate to see his series known as the "The Massey Triad," where Dr. Massey scrutinizes the importance of various experiences and how they have shaped our generations. This series is a little dated, with some of the lectures occurring in the 70s and 80s, with clothing to match. But, the messages and insights are timeless. Here is a good summary of generational values and differences, based on Massey's writings.
