Does a Low Birth Rate Delay Young People's Entrance into Adulthood?

When demographers talk about low birth rates, the usual conversation is about why they are so low. And when consequences of those low rates are mentioned, it is almost always in the context of the negative effect on the age transition--with too few young people relative to the older population. Now, however, we have a new perspective from Jean Twenge, a San Diego State University psychology professor who has written famously about "Generation Me," in which her analyses suggested that younger people were growing up in an age of "entitlement" rather than "enlightenment". Her newest book is iGen: Why Today's Super-Connected Kids are Growing Up Less Rebellious, More Tolerant, Less Happy — and Completely Unprepared for Adulthood.” The San Diego Union-Tribune has a lengthy story about the substance of that book along with a paper on this topic that just came out in the journal Child Development.

Today’s 18-year-olds exhibit similar milestone behaviors as did 15-year-olds in the late 1970s, Twenge said. Moreover, they’re mostly doing this voluntarily — parents aren’t imposing this delayed independence.

But while smartphones and social media enable these trends, Twenge says it’s not the whole explanation. Advances in safety and a declining rate of childbirth drive this process. When parents have fewer children and expect them to grow up, they will expend more care on them.

Twenge said an evolutionary explanation called life history theory appears to be behind the trend. It classifies the maturation of species into “fast” and “slow” strategies.

Fast strategies involve producing prolific amounts of offspring with minimal care. Spawning fish and lobsters are examples. Very high death rates are acceptable, because only a tiny fraction need to survive to perpetuate the species.

Humans, with many years of care and training required for independence, represent the slow strategy. Modern society makes the slow strategy more feasible than before, Twenge said. 

Thus, fewer children per parent enables "helicopter parenting," but Twenge doesn't see that as necessarily bad--just different. Lower death rates with associated greater longevity (including healthy years of life expectancy) diminishes the need for children to rapidly become adults. Indeed, it may be socially useful for younger people to spend longer figuring out how the world works and where they are going to fit into it.