All current sources are on the theory's webpage.
As for colonial America, there obviously are almost no statistics available from US from that period, but there are some statistics from the medieval England, like the one below. Red lines mark a fourth turnings ending. It seems that they align nicely with the sociopolitical instabilities in England, starting from the Anarchy during the 1150's. Every single bigger period of instability, three out of three, correlates with the generational theory.
![[Image: england-sociopolitical-instability-cycle.jpg]](https://jannemiettinen.fi/FourthTurning/england-sociopolitical-instability-cycle.jpg)
When going back centuries, after the 19th century the theory mostly relies on the observations done by Strauss & Howe on parenting, alcohol use, etc. The idea is to use all the data available from 1800 to 2019 to connect the historical observations to cyclical hormone levels.
If this sounds difficult, it is, but so far almost everything has aligned pretty nicely with the hormone theory.
As for colonial America, there obviously are almost no statistics available from US from that period, but there are some statistics from the medieval England, like the one below. Red lines mark a fourth turnings ending. It seems that they align nicely with the sociopolitical instabilities in England, starting from the Anarchy during the 1150's. Every single bigger period of instability, three out of three, correlates with the generational theory.
When going back centuries, after the 19th century the theory mostly relies on the observations done by Strauss & Howe on parenting, alcohol use, etc. The idea is to use all the data available from 1800 to 2019 to connect the historical observations to cyclical hormone levels.
If this sounds difficult, it is, but so far almost everything has aligned pretty nicely with the hormone theory.
Generational hormone theory: https://jannemiettinen.fi/FourthTurning/