The second thing you notice about a stranger when
you meet them is their height. I hardly need mention that the first thing is
their gender. Gender and height has a weak connection in humans in that men are
reportedly ~8% taller than women, but is this important?
This weighty question has received detailed
scrutiny by Stulp et al in the
Journal of Behavioral Ecology and Sociobiology (1). They start off with the
observation from online dating sites that women prefer taller men. Height
appears to be an indicator of greater strength, but physical dominance is not
the be all and end all. It is apparently correlated with social status in terms
of income and education. This was from studies that I’d missed, so I had better
amend my reading habits.
The males of most species have a great interest,
and therefore make an investment, in reproductive success. Social status is
critical in group-living species if the females are going to come your way. But
people are a little different. In terms of social status, we have a dichotomy.
More offspring (meaning greater reproductive success) increases with increasing
income, while more offspring goes with decreasing educational attainment.
Stulp and his coworkers jumped off from this point
and immersed themselves in the metadata accumulated in the Wisconsin Longitudinal Study. They found that 3,578 of the men in that study had their
height recorded as well as the number of their offspring.
The computers were buzzing for a while until they
settled on some correlations. Both years in education and income increased with
increasing height, but not so with reproductive success. We need to note here
that reproductive success is taken as number of children surviving to be able
to spread their genes around.
The peak height for reproductive success turned out
to be 5’ 10” to 5’ 11”. So we average guys score again, or do we? Maybe it’s
just that there are more of us to choose from so more of us get started
earlier. Or possibly, just possibly, height and number of kids are not causally
connected even though the can be correlated.
