Here's a little item which suggests that blue-eyed people are more likely to drink alcohol to overcome an innate shyness or reservation in social settings.
I doubt if such research can be considered conclusive. Even so, I find it interesting because I've noticed myself that there is a certain kind of shyness or reservation in many northern European men.
It will be interesting to see if researchers are able to conclusively link certain behavioural characteristics to a genetic inheritance. If they can do this, it would help to explain some of the "fellow feeling" existing between members of particular ethnic groups. (The "fellow feeling" would be based on sharing a similar set of attributes, and therefore feeling closer in understanding to others and to the group culture.)