The article "Promiscuous Pairing and Beginner’s Mind" (PDF) suggests that you put someone in the pair that knows the least about the particular area of the code base. It also suggests that you swap out the senior member of the pair every 90 minutes or so. Not only will the newbies learn about that area of the code but they will also think differently compared to someone who already knows the area.

Does anybody have experience with this strategy? Does it have any connection with reality?

I found other questions about when to use pair programming and whether to accept a job where pair programming is required, but I didn't find any that are specifically about promiscuous pairing and this "beginner's mind" strategy.

If you are unfamiliar with pair programming, there are interesting articles on Wikipedia and c2.com.