Teaching from mistakes

I find it curious that despite the claims that we learn best from our mistakes, many teachers are reluctant to take advantage of this in teaching.

Well, not reluctant, I suppose, but it's more a matter of wanting things both ways.

In your standard EFL class, we don't typically correct spontaneous errors on the spot (and there are certainly many circumstances where correction would break the flow of the conversation), instead giving "delayed feedback" -- a short period at the end of the class where several of the "big" mistakes of the day are put up on the whiteboard and discussed and corrected as a class.

One of the reasons for this is to avoid drawing attention to the invidual or causing any embarrassment.  However, this means it's too late.  Ten or fifteen minutes later, the student doesn't have the same emotional tie to the sentence and any correction is purely academic.  What makes this into a particularly fruitless endeavour is that most of the time they know the correct answer in theory, but they just fail to apply the correct rule in practice, so the error isn't addressed properly.
But if we look at the various confusions I mentioned last time -- married vs tired, embarrassed vs pregnant, having a cold vs having constipation -- we see that correction is at its most effective when it connects on a very vivid, immediate, emotional level.

I'm not saying we should go out of our way to embarrass and humiliate learners, but that we shouldn't be afraid to take advantage of the humour or absurdity of an error in making the correction more memorable.

For example, I know one fellow Gaelic learner who hasn't really grasped the correct use of possessives, and is wont to say things like "tha mi cat agam a' dol dhan bheat", which means pretty much "I am one of my cats on my way to the vet".  Now, you can correct her with "tha an cat agam" and she might repeat it, but 10 seconds later, she'll be saying it wrong again.  So why not just tell her she's called herself a cat? 

Ok, so you have to build up a certain rapport with the other party to make sure you're doing it in a good natured way, and they feel you're laughing with each other rather than laughing at the other person.

But delayed feedback is almost always too late: a mistake can only lose its power to embarrass when it no longer feels like that particular student's mistake, and if it's not that student's mistake then it's just another restatement of the rule. 

Hang on a minute... let's get this straight.  Delayed feedback isn't correction at all?!?  Not on a personal level.  On a technicality, yes, it is correction, but on an emotional, personal level, it's not.  Or at least not always.

So either correct in time to make a difference, or else find a way to teach that avoids errors in the first place.  (And that's not necessarily as hard as it sounds.)