‘The Origins of You’ explores how kids develop into their adult selves

Everyone has an opinion about what makes people, especially the troublemakers, who they are. Bad parents, bad genes, bad society, bad luck, bad decisions — pick your poison.

Starting several decades ago, four psychologists decided to examine how individuals flourish or flounder over the long run. Instead of jumping into a seemingly endless academic scrum over “nature versus nurture,” they studied how children actually develop over years and decades. Jay Belsky, Avshalom Caspi, Terrie Moffitt and Richie Poulton describe provocative insights from their investigations in The Origins of You.

Developmental researchers acknowledge that many personal and social factors interact throughout life. No single factor can explain, say, why one person pursues a life of crime and another excels in college. Life events and random circumstances tug kids in different directions, making various outcomes more or less probable but never dictating outcomes, the authors emphasize.

Only prospective studies can begin to illuminate the winding paths youngsters travel to become their adult selves. Much of The Origins of You concerns a project — now run by Caspi, Moffitt and Poulton — that has assessed about 1,000 New Zealanders in the town of Dunedin from birth to age 38 (data to age 45 is coming soon). The book also focuses on a study, started by Moffitt and Caspi, that has evaluated more than 1,000 pairs of British twins from ages 5 to 18, as well as another study, in which Belsky was involved, that followed about 1,300 U.S. children from birth to age 15. These investigations are among the few that have assessed a range of psychological and physical measures from childhood into adolescence and beyond.