Penseive and Memory

[jmnabers]

No: HPFGUIDX 132880

I've been thinking a lot about this lately, I think because of what 
looks like a penseive on the new cover. 

Here's my question: Does a penseive show you the memory as it existed 
immediately after you first saw it, or does it show the memory as it 
exists now in your head?

I guess what I'm thinking is that memories are notoriously unreliable 
in some ways. They aren't static, fixed things. For example, lots of 
psycologists do studies of people's memories (for example after 9/11) 
and find that they change over the course of time.

So, the follow-up---can a pensieve be "wrong" and show a memory that 
isn't quite right? And what would that mean for the characters who act 
upon those memories?

Jennifer