In 19th century America, every major aspect of daily life was age integrated. Older and younger people worked side by side in the fields of an agrarian economy. Multigenerational households were the norm. Even those one-room schoolhouses of yore frequently found children and adults learning to read together under the same roof. Indeed, there was little awareness of age itself. People didn’t celebrate birthdays. Most would be hard-pressed even to recall how old they were.

But in the early decades of the 20th century, the drive for efficiency and standardization that accompanied industrialization precipitated a radical reshuffling of American life. A new set of laws and institutions began putting young people together with young people, and older people together with other older people. Gradually the generational twains ceased to meet, and by the end of the 20th century, America had come to approximate what economics professor Andrew Scott, co-author of The 100-Year Life, describes as a state of “age apartheid.”

This separation by age has left us ill-equipped for today’s world, where people are living longer and society is increasingly multigenerational. It has contributed to widespread social issues like ageism, generational enmity, and loneliness. Just as troubling, we’re missing out on the many opportunities for individuals to support one another, and bring the talents of young and old to the task of improving life for all.

With more Americans over 60 than under 18 for the first time in US history, it’s time to reverse this situation in ways that both blunt the ills of age segregation and better realize the benefits of intergenerational interdependence.

Read the full article about age segregation by Marc Freedman and Trent Stamp at Stanford Social Innovation Review.