Now, talking about that, when we do experiments like this that look at sort of fun things like dating around a thing or age difference between a five-year-old and a 20-year-old or a 20-year-old and a 80-year-old, cultures, there's lots of experiments that compare say Western cultures verses Eastern Asian cultures, we'll talk about that later in the course in terms of behaviors, genes, whether you have one gene or another, all those things, are those independent variables? 