I wasn't entirely fair to POV-slippage yesterday (Christine calls it Head Hopping, which I think is a great phrase). I feel it can serve an important function.
This isn't to suggest that it should stay in a finished novel. It should be mercilessly killed in the edit.
But I think that in some cases, it can be helpful.
Take this example from my WIP. This is a first draft and most of it will be cut. You will notice, as per this post, tea is consumed during the making of this scene ;)
Stephen brought Rosie back to his digs after they saw the doctor – his landlady went out every Monday to visit her sister, so the house was empty. Rosie thanked whatever saint was looking down on her for her good luck, then she looked down at her body and remembered just how little good luck she was having lately.
As Stephen poured a cup of tea, Rosie started to cry in earnest.
“Come here,” Stephen said, and he moved to the couch to sit beside her. He cradled her head on his shoulder and patted her hair gently and wondered if he should give in to his impulse to kiss her or if it would make things worse.
She extracted herself from his shoulder and wiped her eyes roughly with heels of her hands, dragging the skin so roughly that she left a trail of tiny wrinkles fanning down her cheekbones. “Where would I have to go? Is it like the laundries?” Rosie had heard of the laundries from Cora, who had probably heard of them from some contact in a mad old lady underground movement.
I see two problems there. First, very obviously, we shouldn't know about Stephen's impulse to kiss her. Rosie doesn't know, so we shouldn't, because we're in her head (he's right, by the way. It would have made things worse if he'd kissed her. Just so y'all know). So when I'm editing, that line will be cut out.
The second problem is a little more subtle. I'm not sure I can get away with Rosie wiping her eyes and leaving the trail of wrinkles. She can't see them.
That said, she also doesn't see herself standing up, opening car doors, and blotting away milk moustaches. She still does these things. Should she do any of them?
I think that if I extract the bit of head-hopping/POV-slippage that takes place, I may get away with the wrinkles. We'll see once I've done it.
Anyway, that isn't the point of this post. The point is that these slips can be useful for a writer.
I feel it's important to Stephen's character that his instinct in this situation is to kiss Rosie, but he doesn't. He knows he's a little out of his depth, he wants to make it better, his only impulse is less than useless and he has just enough sense not to act on it. It's good that I know this before I cut out the line - it helps me to know his character better.
This isn't the place for me to use that knowledge, but I'm sure it will come in useful somewhere, right? :)