Every few years, a new cohort gets a name, a stereotype and a news cycle. Boomers are blamed for the housing crisis, Gen X is largely forgotten, and millennials are said to have killed off everything from napkins to marriage. Gen Z, the story goes, cannot make eye contact but will save the planet. It is a tidy story. The researchers who actually study social change increasingly say it is mostly wrong.
The academic origin
In 1928, the Hungarian sociologist Karl Mannheim published an essay, "Das Problem der Generationen," which is still widely regarded as the founding theoretical text on generations as a sociological phenomenon. Mannheim's actual claim was far more careful than most of what gets attributed to him today. Simply being born within the same span of years does not, on its own, make a group of people a generation. What matters is shared exposure, during youth, to the same formative historical events and social conditions, something Mannheim called a common "generation location." Whether that shared exposure produces an actual shared consciousness, what he termed "generation as actuality," is a separate question again. Even within a single generation as actuality, Mannheim argued, distinct "generation units" can form and respond to the same historical moment in entirely opposite ways, a far more cautious claim than the idea that everyone born between 1965 and 1980 thinks alike.
This is why serious sociologists still take generational analysis seriously in a narrow sense, as a way of asking how coming of age during the Cyprus banking crisis, say, or during a period of relative EU-era stability shapes political attitudes, while treating the pop-culture version, with its fixed 15 to 20-year birth brackets and consumer-personality profiles, as a distortion of the original idea. The sociologist Jane Pilcher, in an influential 1994 reassessment, described Mannheim's essay as an "undervalued legacy," frequently cited but rarely applied with the rigour it demands.
Where the popular labels came from
The familiar named cohorts are a much later and far less academic layer on top of Mannheim's framework, and they arrived from several unrelated sources rather than one unified theory. "Baby boomer" is genuinely demographic, referring to the measurable spike in births across the United States and parts of Europe after 1945. "Generation X" was popularised by Douglas Coupland's 1991 novel of the same name, itself borrowed from a decades-older photo-essay title, with no fixed theoretical apparatus behind it at all.
"Millennial," and the broader habit of naming cohorts after recurring 20-year archetypes, comes largely from a single strand of pop history, William Strauss and Neil Howe's 1997 book The Fourth Turning. The book argued that Anglo-American history moves in recurring 80 to 100-year cycles, a saeculum, made up of four turnings, a High, an Awakening, an Unravelling and a Crisis, each producing a generation with one of four fixed personality archetypes: Prophet, Nomad, Hero and Artist, repeating in a set order. It is a striking, self-contained theory. Strauss and Howe even used it to forecast a national crisis period beginning around the mid-2000s, a prediction some readers have since connected to the 2008 financial crisis, and Howe extended the argument in a 2023 sequel, The Fourth Turning Is Here.
The theory supplied one memorable naming convention and a colourful mechanism, but not the underlying premise that generations exist and matter, which remains Mannheim's much older and more cautious claim. Even readers sympathetic to Strauss and Howe have criticised the archetype system for being difficult to falsify and for fitting almost any historical figure after the fact. One review of the book noted that the same "Nomad" archetype gets applied to figures as different as Ulysses S. Grant and Huey Long, and the "Artist" label to both Andrew Jackson and Walter Mondale, which raises the question of how much analytical content survives once the labels are stretched that far.
The academic backlash
The gap between Mannheim's cautious original and its far more marketable descendants has produced a real backlash in recent years. A 2025 review of generational cohort theory in the International Journal of Advertising concluded that the framework routinely produces oversimplified, deterministic claims about entire birth cohorts, and that researchers consistently find greater differences within a generational cohort than between generations, undermining the assumption that individual members can be reliably characterised by their cohort alone.
The most consequential shift has come from Pew Research Center. Around 2021, Pew began pulling back from generational categories in its reporting, while still using age and birth year to track social trends, and formalised that shift in 2023. Pew itself described generational research as having become "a crowded arena," pointing to a growing chorus of criticism directed specifically at generational labels. The organisation now reserves generational framing for cases where it adds real analytical value, rather than defaulting to standard birth-year cutoffs. The shift followed years of pressure from demographers. In 2021, the University of Maryland sociologist Philip Cohen circulated an open letter, eventually signed by hundreds of social scientists, urging Pew to stop using its generation labels altogether, arguing there is no scientific basis for dividing a population into named cohorts of arbitrary length.
In workplace research, a widely cited analysis by the organisational psychologist Jennifer Deal found that people across working-age generations tend to want the same basic things, a good relationship with their manager, caution around disruptive change, and meaningful feedback, with apparent generational conflict often better explained by seniority and authority than by birth year. A 2024 meta-analysis of workplace studies backed this up, finding few meaningful differences between generations across work values, organisational commitment, stress and engagement. Ipsos's own 30-country research reached a similar conclusion, framing the real driver as career and life stage rather than birth year: Gen Z, millennials and Gen X, in this reading, are largely riding the same workforce waves, just at different points in time. Peter Cappelli, who led a related National Academy of Sciences review, makes the methodological point sharpest. The honest comparison, he argues, is not 25-year-olds against 50-year-olds today, but 25-year-olds today against 25-year-olds a decade or two ago, and when researchers run that comparison, they typically find no real differences in fundamental values and interests.
Real cohort change does exist
Some of the most rigorous long-run evidence in social science does show real, measurable cohort change, just not the kind that fits neatly into a marketing persona. The political scientist Ronald Inglehart's decades-long World Values Survey project is the clearest example. Tracking dozens of countries since the 1970s, Inglehart documented a genuine shift he called a "silent revolution." Among older cohorts, materialist values emphasising economic and physical security were overwhelmingly dominant, but moving from older to younger birth cohorts, postmaterialist values emphasising autonomy and self-expression became increasingly widespread. Crucially, Inglehart tied this to a testable mechanism rather than a fixed personality trait. People who came of age during periods of material security were more likely to prioritise autonomy and quality of life, while those shaped by scarcity prioritised economic and physical security, a hypothesis grounded in formative conditions rather than zodiac-style cohort branding. Even here, later scholarship has complicated the picture. A 2024 age-period-cohort analysis covering the United States, Japan, Türkiye and China argued that much of the value shift attributed to generational replacement may actually be driven by period effects, meaning what changes is the moment in history rather than a fixed cohort personality.
That distinction, between real, historically grounded value shifts and manufactured cohort stereotypes, is the crux of the scientific critique. Nobody serious disputes that people who lived through the Cyprus crisis of 1974, the 2013 banking collapse, or a childhood with a smartphone in hand were shaped by those specific experiences. What the research disputes is the leap from a shared historical experience to a fixed, marketable personality that supposedly determines how a 45-year-old thinks today, permanently.
