What's the Matter With Those Born in 1948 On?

In Bloomberg, economist Tyler Cowen opines:

There are numerous theories as to why [the Great Stagnation started in the early 1970s]: oil price shocks, more stringent government regulations, an increased emphasis on environmental protection over economic growth, and the collapse of the Bretton Woods international monetary order….

Some of those likely are factors. Now an economist, Nicholas Reynolds of the University of Essex, claims to have found a new villain in this economic story: a negative shock to the quality of human capital in America.

Americans born after 1947 [i.e., those born in 1948 and after: most of the Baby Boom] and before the mid-1960s — the first of whom were just entering their prime working years in 1971 — did not see economic gains comparable to those of their predecessors. But the problems of this cohort are more far-reaching. They had more problems as young children, and they did worse in school in the 1960s, accounting for the educational declines of that era, such as lower test scores and higher dropout rates.

Birthweights also declined in the 1980s, a sign that the post-1947 cohort was less healthy, most of all when it comes to maternal health. You might think that development is due to intervening economic factors. But the post-1947 world is still wealthier than what came before, so it is not obvious why an economic slowdown, but not absolute decline, should have created such significant health problems.

It’s not just that Americans born after 1955 stopped getting taller, whereas Europeans didn’t. There are deeper problems, such as the alarming rise in the midlife mortality rate since 1999. These “deaths of despair” may also be a legacy from this 1947 break in Americans’ quality of health. …

Right, it’s clearly tied into economist Angus Deaton’s and Anne Case’s 2015 discovery of a big increase in “deaths of despair” among the white working class. But it’s more likely due to the famous cultural change of the Late Sixties than a decline in American quality of health care.

The obvious question is what exactly happened in about 1947 to put the US on this less constructive path.