[SiVal]

And the fact that all studied traits in all categories were found to have a significant degree of heritability strongly suggests that where groups obviously differ in traits that are easily visible, a similar degree of group difference in non-visible traits is to be expected.

[tjradcliffe]

This does not follow at all, because there is no evidence for any master mechanism that would correlate the group average of one trait with another. So simply because a group can be clustered by one trait there is no reason to expect they will differ from the population average in others.

For example, if you were to sort the population the length of their pinky finger, and then look at two groups of people, one the longest-pinky quintile and one the shortest, there is nothing in this study that would suggest those two groups would have different resting heart rates. This is true even though we can assume on the basis of this work that both pinky length and resting heart rate are about 50% heritable.

The only way they would be correlated would be if there was a single selection mechanism for both, and given that visible traits and non-visible traits tend to have completely different selection mechinisms you'd have to show positively and directly by experiment that such a common mechanism existed in any given case.

Ab initio there is simply no basis for the claim any random non-visible traits like resting heart rate will have different group averages for groups that are segregated from the general population by any random visible characteristics like pinky length.

[SiVal]

No, the grouping I'm talking about is not by some arbitrary trait but by genetic relatedness. Two groups with recent common ancestry within the group and only distant common ancestry across groups.

Genetic similarity is the "master mechanism that would correlate the group average of one trait with another."