Excerpt from Deathly Hallows. It is already revealed in the initial chapters what she did with her parents.
‘You're the boss,' said Ron, sounding profoundly relieved. ‘But I've never done a Memory Charm.'
'Nor have I,' said Hermione, ‘but I know the theory?'
She took a deep, calming breath, then pointed her wand at Dolohoy's forehead and said, 'Obliviate."
It’s not really the same topic, but I always thought that was weird. To me, it sounds like modifying someone’s memory to make them believe something not true would be much harder than simply erasing them.
In HBP, Dumbledore describes the planting of a false memory to be a ‘complex bit of magic’, but it seems much closer to changing someone’s memory, than completely erasing it.
Just my pretty irrelevant 2 cents :)
As a counterpoint, I could see how erasing a memory entirely might be more difficult or more risky than replacing it.
In computer science, removing data from a structure without taking the necessary precautions to ensure the rest of the data remains accessible can be disastrous. In most cases, it's easier and less complicated to change the data rather than removing it completely.
If you have a wall of bricks and you want to remove a few of them completely, you may have to restructure the bricks around them to make sure the integrity of the wall isn't compromised. If you replace them with other bricks it may still be difficult to make the swap initially, but it will be a much less complicated task since you've left the wall in a similar state.
In the Goblet of Fire book (not sure about the movie) there's a dude who owns the fields/land the quiditch world cup is taking place on, who is a muggle. And rather than clueing him in and paying him to keep him quiet, the wizarding government decided it'd be easier to keep erasing his memory, which we see causes (afaik) near irreparable damage to the mans consciousness, who is stated to walk around in something akin to a dream-like state (iirc). (And let's not forget Lockheart, although that was a faulty wand more than anything)
Thus it can be stated with some confidence that yes, erasing someone's memory is much more dangerous to their psyche than changing/altering it.
Would that not be a memory charm? Granted not “Obliviate,” as that erases memories. That could be what she was referring to. She can alter memories, but she never fully erased any.
No, obliviate straight up erases memories. A skilled witch or wizard could use it to erase certain memories. It’s more likely Hermione used the same spell on her parents that Tom Riddle used on Morfin Gaunt.
That’s… exactly what I said. Obliviate erases memories, which Hermione has never done. What I asked was “would a charm/spell that alters memories not be a memory charm?” Hermione was essentially saying that she had never erased memories before.
“The Memory Charm” specifically refers to Obliviate in the books. The M and the C are capitalised, referring to the specific memory spell obliviate.
Okay, do Hermione never cast “the memory charm.” Don’t necessarily agree with the syntax, but I’m not the author.
I'm with you man, a charm that alters memories. Regardless if altering them means erasing them or adding to them or replacing them.
From a web AMA with JKR shortly after the release of Deathly Hallows
"Laura Trego: Did Hermione really put a memory charm on her parents she says she did, but then about 50 pages later tells Ron she's never done a memory charm. J.K. Rowling: They are two different charms. She has not wiped her parents' memories (as she later does to Dolohov and Rowle); she has bewitched them to make them believe that they are different people. "
I’d say she confunded her parents, not obliviated them.
They're different spells.
Hermione has never done "the" Memory Charm (Obliviate). This spell removes memories, and is very difficult to lift - the only example we have of an Obliviate being lifted is when Voldemort does it to Bertha Jorkins, and her mind and body were permanently damaged from it.
What Hermione did to her parents was a different, unnamed spell that bewitched her parents to make them believe that they were different people who didn't have a daughter and whose lifelong dream was to move to Australia. This spell can be lifted without doing permanent damage, since Hermione says that when the war is over, she'll find them and lift the enchantment. While this could perhaps be referred to informally as "a memory charm" since it impacts memories, it is not a capital letter "Memory Charm", which is the proper name of the specific spell that Obliviate is the incantation for.
Hermione presumably knows the theory of the Memory Charm (Obliviate) because when she was researching what to do to her parents, she considered the Memory Charm and decided against it because it didn't suit her needs - she likely wanted something that was more easily reversible.
Obliviate erases memories. Hermione had modified her parents' memories. They are different spells, but the movie had her use Obliviate while the second's incantation isn't stated in the books.
In addition to the answers here, we know Hermione wouldn't use Obliviate on her family, especially after seeing what it did to Lockhart.
She only did the memory charm on her parents in the movie. In the book she modifies their memories so that they think they don’t have a daughter and that they want to go to Australia. It isn’t said what spell she used specifically.