How the "Accident Hump" Tells Us Boys Are Maturing Faster

We’ve known for a while that girls have been maturing at a faster rate for much of the last 100 years, if not longer. Disease reduction and better nutrition are thought to be the biggest factors. But what about boys? Researchers have long thought they were maturing faster too. But lacking the obvious (monthly) data, the evidence proved tricky.

Now, a German researcher believes he’s found the answer by looking at, of all things, male teenage death rates. When girls hit puberty, they get their period. When boys hit puberty, they start doing stupid stuff, hence what’s called “The accident hump,” a spike in mortality rates that coincides with the peak of male hormone production during puberty. That hump it seems has been shifting to earlier and earlier in life.

The new study, by Joshua Goldstein, director of the Max Planck Institute for Demographic Research in Rostock, Germany, finds that the age of sexual maturity for boys has been decreasing by about 2.5 months each decade, since at least the middle of the 18th century.

Here’s the abstract:

This paper shows new evidence of a steady long-term decline in age of male sexual maturity since at least the mid-eighteenth century. A method for measuring the timing of male maturity is developed based on the age at which male young adult mortality accelerates. The method is applied to mortality data from Sweden, Denmark, Norway, the United Kingdom, and Italy. The secular trend toward earlier male sexual maturity parallels the trend toward earlier menarche for females, suggesting that common environmental cues influence the speed of both males’ and females’ sexual maturation.

As Goldstein puts it in a quote from the study’s press release: “Being 18 today is like being 22 in 1800.”

But while we’re maturing faster physically, we’re also delaying many of the hallmarks of adulthood: getting married, having kids, and achieving financial independence are all tending to happen later and later in life.

“The biological and social phases in the lives of young people are drifting apart ever stronger”, says Goldstein. “While adolescents become adults earlier in a biological sense, they reach adulthood later regarding their social and economic roles.” Life cycle research shows that for more than half a century the age at which people marry, have children, start their careers and become financially independent from their parents continues to rise.

Though as Goldstein points out, this biological and social maturation gap may have its advantages: