People tend to shrink with age, especially after age 50 or so. It has to do with spaces between the joints amount of cartilage and posture. Bone length does not change.

Taller people tend to earn more on average, although the effect is modest. This is clearly true in occupations where strength is important but also a relationship exists in other occupations as well. It could be perceptions, as you say or something systematic. It's somewhat of a mystery.

Genes are very important at the individual level but these differences tend to cancel at the national level.

There are some effects of the biome. Compact bodies tend to conserve heat relative to linear ones. This can affect average height as well as body proportions. The study participants Europeans and Americans do not fall into the range where this effect is powerful, however.

All the Americans in the study were native born, but the height of the mother does affect the growth potential of the child. So, there is a second generation effect. But this can explain only a small portion of the height difference between Americans and northern Europeans. Regarless of continent of origin, children who grow up under conditions of good health and nutrition are about the same height, on average.

People tend to shrink with age, especially after age 50 or so. It has to do with spaces between the joints amount of cartilage and posture. Bone length does not change.

Africans are not as tall as northern Europeans. But Manute Vol and other sports figures in basketball and football receive a lot of press coverage.