Marked by Time examines how the moment in history when we are born shapes who we become. I call this the “birth lottery of history.” Put in the strongest terms, when, not who, matters most for understanding the life trajectories of young people.

Most research on children’s development follows a group of people born around the same time—a single birth cohort. But as children grow up, the world around them is also changing. Individual development and social change are intertwined; you cannot really understand one without the other.

To tackle this challenge, my book studies multiple cohorts of more than 1,000 children who came of age at different points over the past three decades. Exploiting this unique design, I show how societal shifts shape people’s chances of being arrested, being exposed to violence, using guns, or even dying young.

By shifting attention from who to when, the book challenges common beliefs about criminal propensities or fixed “character.” We often imagine character as a stable core of traits that guide our actions and define who we are. This view has a moral valence: people are seen as simply good or bad. Ideas about criminal propensity and character are deeply embedded in everyday thinking and in the criminal justice system, even though history is an integral part of the indicators we often use to define an individual’s character, such as an arrest record.

This blindness to social change produces what I call the “character trap”: a self-reinforcing cycle that labels and punishes people based on assumed, innate criminality. But this can backfire, cutting off social ties and leading those criminally labeled to conform to those same negative expectations. 

A possible misunderstanding of my work is that it denies individual agency or responsibility. But that would be a mistake. Instead, I show that young people’s choices and capacities are shaped—sometimes dramatically so—by the changing social worlds in which they grow up. To understand who they become, we must first understand the times they were born into; Marked by Time traces those times.

Ongoing thread. More from Robert J. Sampson to follow.

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