ACambridge scientist speaking ahead of a meet on brain development at the Academy of Medical Sciences in Oxford has made headlines worldwide by suggesting that we don’t grow up until our thirties. The excitement is unwarranted. Compelling data from thousands of years of juvenile behaviour establishes that on average, humans never grow up at all. Just six months ago, speaking at the Leverhulme Centre for the Future of Intelligence at Cambridge, Stephen Hawking, who was a professor there, defined the discipline of history as the study of the history of stupidity. The human race has worked for centuries to create civil society, to stave off a life that looked “nasty, brutish and short”, in Hobbes’ (the gloomy political philosopher of Malmesbury, not the cartoon tiger) memorable phase in Leviathan. Having largely achieved that aim, it now seeks salvation in many countries in the search for a lost golden age, guided by strong men. It’s unbelievably juvenile.
The headlines that scientists made at Oxford were ridiculous, but what they actually said was not: That the minds of people mature at different rates in a continuous process, and that we do not all suddenly become adults either at 18, or 21 or 30. Watersheds for attaining adulthood are illogical compacts that have been agreed upon by interest groups that must administer justice, deliver education and health, sell alcohol and tobacco or conscript for military service. In reality, the brain keeps rewiring itself throughout the first half of life, and does not reach a steady state until the age of 30.
So now we know that while the exhortation to “act your age” is illogical, the demand that you “grow up” is not. And also, that you have at least a decade extra to run wild. Life is short, and it’s always nice to have a margin.