Here's Part 4 of the blog series I'm writing John Williams themes: http://www.filmmusicnotes.com/john-williams-themes-part-4-of-6-the-raiders-march-indiana-jones-theme/ Have a look if you're interested.
I've tried asking Pete Docter on his Twitter page regarding this, but I don't think he uses it frequently so it will be hard to say if we'll have an answer or not... Is there any way we can find more about this? Edit: I created a Twitter account solely for this. Just like when I created a Facebook page just to ask Conrad Pope about TIntin