There's more truth to that than some might realize.

Imagine child's brain, virtually empty.  Only rudimentary pieces of information and very little contrary information.  That is one of the reason they lack critical thinking. 

Now consider a 50 year old brain.  It's filled with information and contrary information.  Just like the ag cafe.  When a question arises that brain has to shift through a lot of things just like a hard drive has to flip back and forth to find all the pieces of a program or document.  It takes longer and sometimes it gets corrupted. 

Maybe someday there will be a defrag method for the human brain.