Cycle No. 10 · Quantitative
Turchin (50y) — fathers-and-sons cycle
~50-year 'bi-generation' oscillation in US political violence, superimposed on the longer secular cycle - spikes of unrest roughly every two generations, once living memory of the last convulsion fades
- Period
- 50 years
- Reference peak
- 1970
- Paired data
- None this round
Peak calibration
Most recent stated peak, in Turchin's own words: 'a 50-year oscillation superimposed on the secular cycle, with peaks around 1870, 1920, and 1970' (Journal of Peace Research 49(4), 2012). With period 50 and peak 1970, this sinusoid's prior peaks land exactly on his other two stated peaks (1870 and 1920) and the next lands at 2020. Turchin himself extends the sequence to 'around 2020' in the same paper, while explicitly calling that a simple projection rather than a scientific prediction; it also coincides with the instability forecast of his separate 150-year secular cycle, so the two Turchin curves on this site peak together at 2020 by construction, not as corroboration. The paper attributes the mechanism to the 'fathers-and-sons' dynamic - an additional process he treats as distinct from the core structural-demographic theory - and prefers the term 'bi-generation cycles,' with recurrence 'roughly two generations (40–60 years)'; 50 is the headline number and the one used here.
CaveatSame author as the 150-year secular cycle - a distinct construct from a distinct paper, not independent corroboration. Turchin describes the observed ~50-year pattern as sharply peaked, not sinusoidal; the cosine here keeps only his recurrence interval and reference peaks, not his waveform. No paired data series: Turchin posts the underlying US Political Violence Database (USPVD2010.xlsx; 1,590 events, 1780–2010) on his site, but it carries no explicit reuse license, so this site does not redistribute it.
Confidence classification: Quantitative — the period comes from statistical work on historical data. Every cycle on this site is a pure sinusoid built from the theory's stated period and one documented reference peak — a deliberately naïve construction, so that disagreement between theories rather than parameter fitting is what you see. See about for why nearly every cycle peaks near the present.
Where this curve plots its extrema
Computed from period 50 and reference peak 1970, across the site's default window (1600–2050). These are positions of this construction, not dates claimed by the theorist.
- Peaks
- 1620 · 1670 · 1720 · 1770 · 1820 · 1870 · 1920 · 1970 · 2020
- Troughs
- 1645 · 1695 · 1745 · 1795 · 1845 · 1895 · 1945 · 1995 · 2045
Paired data series
None in this version. No long-run series in this project maps cleanly onto Turchin (50y)'s construct. The curve can still be overlaid against any of the other series in the interactive chart, but it has no dedicated empirical pairing to be stress-tested against.
Reuse this
Kooi, D. (2026). Sinusoidal History: Turchin (50y) — fathers-and-sons cycle. https://sinusoidalhistory.com/cycles/turchin-fathers-sons · DOI 10.5281/zenodo.21998618.
Our code and the original chart files are MIT-licensed as our own work. The plotted data stay under their upstream terms, listed above: CC BY series carry their attribution requirement with them, and a series with no explicit license is shown here without any grant we can pass on. Reuse our figures and code with attribution; honour the data terms for the plotted series.
Open this cycle in the interactive chart to calibrate its peak and period against the data, or compare it with the other nine on one axis.