If you were feeling sad right now and you recall a sad - or, a very happy memory from the past, it will be tinged with more sadness based on your current feeling. So we felt like that was actually on solid scientific ground .

Every time you recall a memory, you're basically making another copy of it and at that same point it is susceptible to new changes and adaptations. So, you know, if you remember from when you were, you know, in second grade and there was Christmas and you got a present from your grandfather and your mom was wearing a red dress, that may or may not all have happened.

But the truth is, at some point, our films - almost every single one of them - are really bad. And it's largely hats off to John Lasseter and Ed Catmull who have set up a system whereby they're expecting it.

And usually I'm not watching the screen. I'm kind of sitting and looking off to the side, spying on people to see what they react to' cause it's - as Joe Ranft used to say, you know, animation is like telling a joke and waiting for three years to see if anyone laughs

So this idea of moving seemed like a good way to sort of represent that metaphorically. It also is something for me personally. When I was in fifth grade - so about 11 - my folks moved us to Denmark.

It might have been introduced slowly over the course of the years as you recall this memory over and over. So that was a very cool but complex idea that we thought about representing in the film but could not find a way to make it work.

Yeah, to bring families together I need to go away.