09/30/2011 12:05 am ET | Updated Nov 29, 2011

Staking Out the Territory

Over many years of writing and consulting about baby boomers there is one question I'm asked far more often than any other: What exactly is a baby boomer?

It is a curious question given all the press about boomers since they were in diapers. (The first cover story about boomers appeared in Newsweek in 1948.) But the fact that few people have a clear sense of the generational identity of these 78 million people hasn't stopped anybody from nattering on about them. However, before we get drawn into yet more boomer chat, let's take a moment to circle back and stake out the territory.

The muddle about boomers arises partly from a presumption that the '60s forged boomers. Untrue. The '60s were the heyday of people then in their 20s and 30s, or those born in the 1930s and early 1940s. The baby boom didn't start until 1946.

Jane Fonda, Abbie Hoffman, Gloria Steinem, Ken Kesey, Timothy Leary, Bob Dylan, Joan Baez, Jimi Hendrix, Jim Morrison, Janis Joplin, Jerry Garcia -- and on and on -- were all born before the fertility boom from which boomers sprang. Not that the '60s weren't important; it's just that the current carrying boomers runs deeper.

To properly define boomers, you have to start with numbers. The twentieth century-long decline in U.S. fertility rates was interrupted only once, and that was during the 19-year-long post-WW2 baby boom. In 1946, births per thousand exceeded 100 for the first time since 1927 and remained so -- peaking in 1957 -- every year through 1964, the end of the boom.

Graphically, this resembles the infamous pig in the python. There's no ambiguity about it. It has a clear beginning and end, with a huge jump from 1945 to 1946 and a sizable drop from 1964 to 1965. By the numbers, boomers are easy to define.

But 19 years is a long time. The late '60s to the mid-'70s to the late '70s covers the Tet Offensive to Watergate to hostages in Iran, psychedelic rock to arena rock to disco and punk, tie-dye to platform shoes to leisure suits. Life was not the same for all boomers. Some argue that these disparities disprove the very possibility of a cohort in common. But these social events tell just part of the Boomer story, and not even the most important part.

What marked Boomers for life was coming of age in a time of profound economic optimism and confidence.

The three decades after WW2 saw the American economy in unrivaled ascendance, like nothing before or since. The Boomers who grew up together in unprecedented numbers came of age in this glow, convinced that, even with problems aplenty to fix along the way, their parents' vision of the 1964 World's Fair was in the offing.

They took it for granted that their own rule-breaking self-indulgence would forever be secured (and forgiven) by a vibrant, if turbulent, economy. Naïve, yes, but it seemed certain then. This is what makes Boomers distinctive. It is the rare generation in American history -- none since Boomers -- that grows up with so much and the certainty of so much more to come.

Not every Boomer fits the stereotype. But all Boomers shared the experience of growing up in a time when economic triumphalism catalyzed personal enrichment, self-expression and egoism. To paraphrase Daniel Yankelovich -- one of the first scholars to study Boomers in-depth -- the self-indulgence of this generation replaced the self-sacrifice of the prior generation as the main measure of success. A culture war split Boomers in two, but both sides, whether they realize it or not, share the generational hallmark of self-absorption.

Ultimately, though, the expectations that defined Boomers as a cohort double-crossed them in life. Raised on the promise of more, Boomers have had to navigate the reality of less. Hard on the tail end of Boomer numbers, the assurance of economic good times fell through -- the promise was betrayed by circumstances.

The repeated disappointment of youthful expectations is the continuing story of boomers. Hit with it first in the late 1970s and early 1980s, they were hit with it again in the early 1990s, then again in the early 2000s, and are now facing it yet again today. Boomers built their lives on a promise that has proven elusive.

In short, properly defining Boomers is not an academic exercise. It goes to the heart of their experience and the soul of their future. Boomers will always be the generation on the look out for fulfillment. Whatever their bluster to the contrary, they pursue it still, embracing whatever gambit they can to close the gap between promise and reality.