Sobre a figura acima? Nas palavras do grande John Komlos:
This graph shows an interesting episode in the American economic history: While per capita income was rising during the industrialization, average heights of the free (male) population decreased among the cohorts born in the decades preceding the Civil War. Therefore this phenomenon is called the Antebellum Puzzle. Several articles in the publications section of our website are devoted to the analysis of such puzzling episodes in the history of the biological standard of living.
Claro, a dica é procurar pelo tema na internet.