Schlagwörter

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Hair Color and Eye Color
in Northern Germany, Central Germany, Southern Germany, Austria and Switzerland

© PD Dr. Ronald Henss

Recently I have published some statistical data on the co-occurence of different hair and eye colors in different German sample.

I a personal communiaction Peter Frost, a leading expert on hair (eye and skin) color resarch, asked: "Does the correlation between hair color and eye color persist if you analyze the data within smaller geographical areas (e.g., länder)? I am raising this question because correlations between hair, eye, and skin
color are often artefacts of population differences. For instance, both hair color and eye color tend to be darker in southern Germany than in northern Germany. If the data are pooled for all German subjects, one would find a significant correlation between hair color and eye color. This correlation, however, would be due to population substructure and not to some kind of genetic linkage (e.g., pleiotropy)" (E-Mail, February, 14, 2008).

To answer Peter Frost’s question, I have broken the German data set into three regions:
Northern Germany (Schleswig-Holstein, Hamburg, Bremen, Niedersachsen, Mecklenburg-Vorpommern); N=1491
Central Germany (the remaining "Bundesländer"); N=5142
Southern Germany (Baden-Württemberg, Bayern); N=2577
Additionally I included the data from Austria (N=1082) and Switzerland (N=645).

Note: The frequencies of hair colors in the German subsamples have been reported »»» here

The co-occurance of hair and eye colors within each region (country) are reported in the following tables.
Within each row the percentages add up to 100 per cent

N=1491 Northern Germany
   blue    grey    green    brown   mixed
light blond 61.2 1.5 17.9 3.0 16.4
medium blond 46.9 5.5 22.4 6.1 19.0
dark blond 40.2 4.1 19.5 17.1 19.0
light brown 27.6 3.1 17.3 28.3 23.6
medium brown 20.6 4.0 18.8 35.4 21.1
dark brown 15.7 0.5 14.7 44.6 24.5
black 10.9 2.2 4.3 71.7 10.9
N=5142 Central Germany
   blue    grey    green    brown   mixed
light blond 57.9 1.7 20.8 3.9 15.7
medium blond 46.5 6.0 20.8 8.8 17.9
dark blond 36.2 4.8 20.0 16.4 22.6
light brown 23.4 3.4 23.6 29.4 20.2
medium brown 17.6 3.2 19.2 36.8 23.1
dark brown 11.3 1.8 15.5 52.4 18.9
black 10.7 0.6 11.9 65.5 11.3
N=2577 Southern Germany
   blue    grey    green    brown   mixed
light blond 61.8 4.5 19.1 3.4 11.2
medium blond 49.3 5.5 21.4 7.9 15.9
dark blond 38.5 5.2 19.5 17.4 19.4
light brown 29.1 5.7 23.5 25.7 16.1
medium brown 21.4 2.5 17.2 43.1 15.8
dark brown 15.3 2.2 18.2 50.7 13.7
black 3.9 2.6 13.0 74.0 6.5
N=1082 Austria
   blue    grey    green    brown   mixed
light blond 65.6 6.3 12.5 6.3 9.4
medium blond 49.7 2.0 18.3 11.8 18.3
dark blond 42.1 3.8 17.2 17.7 19.1
light brown 30.8 3.8 24.1 27.1 14.3
medium brown 20.2 3.6 22.2 36.3 17.7
dark brown 10.7 2.1 11.5 58.5 17.1
black 6.3 — 15.6 62.5 15.6
N=645 Switzerland
   blue    grey    green    brown   mixed
light blond 70.0 — 20.0 — 10.0
medium blond 44.4 2.8 25.0 8.3 19.4
dark blond 36.0 4.4 17.6 20.6 21.3
light brown 23.3 5.5 24.7 27.4 19.2
medium brown 22.5 2.0 18.5 35.8 21.2
dark brown 11.0 1.4 17.9 51.7 17.9
black 4.2 4.2 4.2 83.3 4.2

The tables reveal a clear co-relation between hair color and eye color.
The columns "blue" and "brown" are of particular interest: The proportion of blue eyes is continuously decreasing from light blond across medium blond, dark blond, light brown, medium brown, dark brown to black. And the proportion of brown eyes is continuously increasing in the same order. Without any exception this pattern holds for each subgroup. Thus, it is clear that the correlation between hair and eye color is not an artefact of pooling different subgroups.

It should be noted that the data were procured from an online survey, and they are not based on a representative samples.