(It’s good to see you back, Dr. Charlton. I hope this means you find this a blog worth reading.)

If the population studied was, for example, college students from a particular university; then this is essentially selecting a relatively narrow band of IQ – and therefore narrowing the range of reaction times to Much less than the IQ range across the world.

i.e. IQ of student subjects would be high enough to get into that college – so that probably all the subjects in the study had above average IQ for that country.

Also, in most colleges except the most-selective ones, the IQ of subjects tends not to include the highest levels – because these students would usually have chosen to attend more-selective colleges.

Anyway, IF the studies were done on US students at a particular college or a few colleges, this is not representative of the situation across the world.

I say this, because it is well established that simple reaction times (like IQ) have large average differences between races – shortest sRTs in East Asians, longer sRTs in white Europeans, longer again again in Sub-Saharan Bantu Africans and so forth.

Given that races often have different skin (and eye) colours on average, there is almost-certain to be differences in simple Reaction times based on skin colour, IF the sample studied has not been pre-selected (as with college students) to exclude the extremes of slowest (fastest) RT subjects.

Of course I haven’t read the methodology of the studies cited by Morgan Worthy, and it may be that the samples were other than I am assuming!

I just mention this as a very common and very misleading error made in many thousands of published psychology experiments: i.e. by the sampling method used, accidentally controlling away almost all of the variation that is being sought. And ending up measuring something else, a confounder!

Where Worthy says ‘hunting’ maybe try ‘sex’? Stalking, Skulking, and Speed/Power.

Some theories:

1. The hit to reaction time comes with a better sense of timing as per Morgan Worthy. Based on his positions/eye color correlations I would guess this would select to some percentage of the population and then we would have an equilibrium. His correlations generally show the few having blue eyes – leaders, QBs, and so forth.

2. Also from Morgan Worthy, blue eyes are better suited for the lower light conditions of northern foggy areas. Might have something to do with circadian rhythm entrainment, or not.

3. Sexual selection under strict monogamous conditions from Peter Frost. The idea being that females have to stand out from other females in some obvious way. This theory would also lead to mixed equilibriums as the competitive advantage of colorful eyes diminishes when more and more women have them.