TIP vs TLT

So we've been discussing both TLT and TIP as potential investments.  They seem to move in relative synchronization, depending on how the stock market does, however this doesn't make a lot of sense.  TIPS should really come into their own during a recovery, while long term treasuries are better in the deflationary environment.  I can see the cases for both but I think it's odd that they seem to move together.