It's worth noting that these couples were all recruited from Berlin, so there may be an element of cultural bias being exhibited. I'm not saying I necessarily d

It's worth noting that these couples were all recruited from Berlin, so there may be an element of cultural bias being exhibited. I'm not saying I necessarily doubt the conclusions, but I have to imagine that if you studied married couples from rural Japan, the slums of Rio, Manhattan, and nomadic tribes in central Asia, you'd find very different things.