Generations: The Real Differences Between Gen Z, Millennials, Gen X, Boomers, and Silents―and What They Mean for America's Future

Published in 2023, Generations: The Real Differences Between Gen Z, Millennials, Gen X, Boomers, and Silents—and What They Mean for America’s Future is a work of social psychology by Jean M. Twenge. Drawing on 24 datasets comprising approximately 39 million people, the book analyzes the six living American generations to argue that their differences are driven primarily by technological change rather than by major historical events experienced at formative ages. Twenge presents her central thesis, the “Technology Model of Generations” (5), which identifies technology as the root cause of generational differences. This model proposes that technology has fostered two overarching cultural shifts: The Generational Shift Toward Individualism and The Adoption of the Slow-Life Strategy.

The book traces how these forces have shaped each generation, culminating in Twenge’s argument that smartphones and social media have contributed to Gen Z’s mental health crisis. Twenge’s analysis challenges the model of recurring generational types made popular by William Strauss and Neil Howe in their own Generations (1991) and The Fourth Turning (1997). Author of the previous generational studies Generation Me and iGen, Twenge examines how Technology as the Engine of Cultural Change has reshaped aspects of life including family structure, political beliefs, work, and personal identity. Generations was selected as a Must-Read Book pick for April 2023 by the Next Big Idea Club. 

This guide refers to the 2023 Atria Books hardcover edition.

Content Warning: The source text and this guide contain discussions of racism, gender and/or transgender discrimination, religious discrimination, antigay bias, mental illness, suicidal ideation and/or self-harm, death by suicide, substance use, illness, and death.

Summary

In Generations, psychologist Jean M. Twenge examines differences among the six living American generations, which she terms The Silent Generation, Baby Boomers, Generation X, Millennials, Generation Z, and the emerging Polars. Drawing on 24 datasets comprising approximately 39 million people, Twenge argues that major historical events such as wars and recessions do not primarily explain generational differences. Instead, she proposes her “Technology Model of Generations” (5), which identifies technological change as the primary cause of long-term cultural and generational change. Twenge argues that technology shapes generations both directly and through two related cultural trends: increasing individualism and a slower life trajectory.

Twenge defines individualism as a cultural shift away from the rigid social rules, group-oriented duties, and conformity of the mid-20th century toward a focus on the self, personal choice, equality, and self-expression. The second key trend, the slower life strategy, describes an overall shift toward reaching developmental milestones later in life. Driven by factors like longer lifespans, higher educational requirements, and increased parental investment in fewer children, this slowdown manifests in adolescents delaying adult activities like driving and dating, and young adults postponing marriage, parenthood, and careers. Twenge argues that technological change and its associated shifts toward individualism and a slower life have disrupted the recurring generational types proposed by older cyclical theories of generations.

The book traces the progression of these trends across the generations, examining how technology, individualism, and the slower life strategy manifest differently within each cohort. Twenge describes Silent activists as being at the forefront of the civil rights, feminist, and gay rights movements, while Boomers increasingly embraced self-fulfillment, personal choice, and self-expression. Generation X, the often-overlooked “middle child” generation, was the first to grow up entirely within the highly individualistic post-1960s culture, and Twenge associates the generation with self-reliance, materialism, and distrust. They were also the last to experience an analog childhood and the first to enter young adulthood in the age of the internet.

The book next turns to Millennials and Gen Z, among whom these trends continue. Millennials were raised during an era of peak optimism and self-esteem-focused parenting, resulting in a generation defined by high expectations and unprecedented self-confidence, which later collided with the harsh realities of the Great Recession. Gen Z, whom Twenge also calls “iGen,” is the first generation to experience smartphones as a major part of adolescence. The slow-life strategy is particularly pronounced among Gen Z, with Gen Z teens delaying adult activities far more than any previous generation. More consequentially, Twenge argues that smartphones and social media are a primary cause of the severe mental health crisis—marked by soaring rates of depression, self-harm, and suicide—that began among teens around 2012 and has since spread to young adults. Using international data, she argues that this crisis has also emerged across multiple countries during the smartphone era. Twenge then considers the Polars, the generation born beginning in 2013, whose early lives have been shaped by the COVID-19 pandemic, political polarization, and concerns about climate change. Because most Polars are still children, she treats predictions about their future characteristics cautiously.

Finally, Twenge uses generational data to project how these shifts will shape the future of American society. The decline in religious belief, the delay of marriage, and falling birth rates are presented as outcomes associated with a more individualistic, slower-paced culture. Politically, she forecasts continued polarization, as generational divides on social issues, race, and the role of government shape American politics. In the workplace, she argues that Gen Z will place greater emphasis on flexibility and mental health support. Throughout the book, Twenge argues that generational differences reflect technological and cultural changes rather than being inherent qualities of particular generations. Understanding these differences, she argues, can help people better understand other generations and prepare for future social change.