A question about Face Recognition

I haven't really had the time to do a full entry about my thoughts on this year's Macworld announcements however you can get a pretty good idea of what I was thinking if you look back at my tweets from Tuesday. To make a long store short I'm actually REALLY excited about iPhoto '09 because it's what I used to manage all my photos and they've really added some great features by the looks of it.

Not the least of those features is face recognition. Read the link for more info but the idea hear is that it will automatically detect people's faces and then you can tell iPhoto who that person is.  As time goes buy iPhoto will gain a better understanding who who the person is and automatically detect and tag that person as new photos of them are added to the library.  The demos of this both in the keynote and the one I got at the Apple booth appeared to work quite well.

However, here's my question: How does this technology deal with people's change apparences over time? I have pictures of myself in my library for example and some of them are when I was about 6 years old and some of them are a few days ago, some of them I'm clean shaven in and others I have facial hair.  How's hat going to work? For some reason my gut tells me not all that well.  But then again I suppose the FBI probably has to take that into account so maybe there is an algorithm to deal with that kind of thing somewhere.

Anyone have any thoughts on this?