Can one tell whether a Northern European is likely to be (dis)agreeable or not simply by looking at the colour of their eyes? Dr. Elliroma Gardiner and colleague, Professor Chris J. Jackson believe you might be able to. They recently performed a study which tested the hypothesis that “… light eyed individuals of North European descent would be less agreeable (a personality marker for competitiveness) when compared to their dark eyed counterparts, whereas there would be no such effect for people of European descent in general.” And the results of their experiments (conducted to test the idea) supported their hypothesis. In that, according to the findings, light-eyed (Northern European) persons are more disagreeable.
Details can be found in their paper: Eye color Predicts Disagreeableness in North Europeans: Support in Favor of Frost (2006) (Current Psychology,Volume 29, Number 1, 1-9)
Note (1) : From their faculty photos, it seems that both researchers have dark eyes.
Note (2) : Professor Chris J Jackson of the University of New South Wales, Australia, should not be confused with Professor Chris J. Jackson of the University of Queensland, Australia, (who has blue eyes).
Note (3) : The irises in the photos above are provided courtesy of the Iris Database at the Dept. Computer Science, Palacký University in Olomouc, Czech Republic.