On the nature nurture debate...

My favorite analogy was in a textbook I had. It said that it is the equivalent of saying, how much of the music is the violin and how much is the violin player?

An interaction means that factors on both sides influence each other. For instance, if you have shy parents, inherit genes which contribute to shyness, you also will have parents who are more likely to introduce you to environments which promote shyness. They may not have company often, they model behaviour which teaches the child how to be in the world... epigenetics states that environments can even influence how our genes are expressed. This is why the nature nurture debate is no longer relevant in psychology. To say that anything should be up for debate, well, creationists say the same thing about Darwin. Also, there are huge methodological issues with adoption and twin studies.

Mentioning nature nurture in the social sciences will get you laughed out. Not because the dichotomy acknowledges more variables but because it fails to acknowledge them and the complexity involved.