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

Large datasets used to identify population-level patterns and changes over time. The author draws on large, nationally representative datasets collected over several decades to compare behaviors and attitudes across generations.

A term for deaths from suicide, drug overdoses, and alcohol-related liver disease. The author applies this concept to explain increased death rates among middle-aged Boomers and, later, Millennial young adults, linking these trends to the erosion of social connection and community support that she associates with increasing individualism.

A cultural system in which people believe in their inherent worth regardless of what others think of them. Sociologists Bradley Campbell and Jason Manning contrast this concept with victimhood culture, describing a dignity culture as one in which people are expected to handle slights privately rather than seek outside assistance.

A psychological belief that one’s life is determined by outside forces like luck or powerful people, rather than by one’s own actions. The author identifies a rise in this belief among Gen Z, linking it to a greater tendency to perceive discrimination, a sense of defeatism, and a belief that “the cards are stacked against you” (428).

A concept from life history theory describing an adaptation to environments with higher mortality rates and where children may be needed for physical labor. This strategy involves having children earlier and in greater numbers, with the expectation that they will grow up quickly and become independent sooner. The author applies this to explain the life patterns of generations before the mid-20th century.

A core cultural trend and one of two major consequences of technology in the author’s model. As a worldview, it places greater emphasis on the individual self, personal choice, freedom, and equality, while de-stressing social rules and group harmony. The book traces this worldview’s steady increase from the mid-20th century onward, showing, for example, how Gen Z members are far more likely than Boomers to report prioritizing personal fulfillment over group obligation—a gap the author attributes directly to decades of individualism’s expansion.

An explanatory framework used to analyze generational shifts in developmental timelines. The theory posits that people adapt their life strategies based on their environment; in safer, more stable environments with longer life expectancies, a “slow life strategy” is favored, while a “fast life strategy” is more common in environments with higher mortality rates (15).

An acronym for “Not All [X] Are Like That” (24), which the author identifies as a flawed argument against generational analysis. It is the mistaken belief that a rare counterexample or individual exception disproves an average, data-supported trend (e.g., arguing generational differences in online time don’t exist because one knows a Gen Z teen who is rarely online).

The author’s coined term for the generation born between 2013 and 2029. The name is derived from two defining issues of their era: political polarization that intensified in the 2010s and global warming, symbolized by the melting polar ice caps (2, 451).

A phenomenon where employees do the minimum required at work rather than going above and beyond. While popularly associated with Gen Z, the author notes that the underlying ethos of disengaging from a “work, work, work” culture has roots in the “slacker” image of Generation X (469).

A term describing the documented decline in sexual activity among younger generations. The author shows that Millennials, and especially Gen Z, are having less sex and are more likely to be sexually inactive than Boomers and Gen X were at the same ages, despite the prevalence of dating apps.

A central concept in the author’s framework, described as an adaptation to modern environments with longer life expectancies and greater resource competition. This strategy involves having fewer children, postponing adulthood milestones like marriage and careers, and nurturing children more extensively. Technology’s role in spreading this strategy across modern generations makes it one of the two major downstream consequences of the Technology Model (15, 18).

The book’s primary unit of analysis, defined as cohorts of people born around the same time who experienced a similar culture while growing up. This concept is distinguished from familial generations (e.g., grandparents, parents, children) and is used to explain broad societal shifts in attitudes, behaviors, and values.

The author’s central explanatory framework for why generations differ. Technology, in this model, works as the originating cause (what the author calls the “mother turtle,” meaning the primary driver from which other effects flow), producing two downstream cultural consequences the author labels “daughter turtles”: the rise of individualism and the adoption of a slower life trajectory. Rather than treating generational change as cyclical or primarily driven by major historical events, the model predicts that as technology advances in a consistent direction, the cultural shifts it produces will follow a similarly consistent pattern (6, 9).