While driving home from karate class tonight, I was singing along to a song (yes, I sing when alone in my car) and accidentally made a spoonerism of one of the lyrics. In this case, it was the phrase "green dress" getting turned into "dreen gress". (Bonus points to whoever can identify what song I was singing.) This got me to wondering what actually causes spoonerisms. It also got me wondering whether there might be a corresponding physical manifestation of spoonerisms - i.e. accidentally switching two physical movements in a series.
For example, every once in a while in karate I'll completely botch a certain move in an odd way. It's not like I forget how to do something (well, I do that, too, but that's not what I'm talking about right now), but instead my brain transposes the actions and it comes out what I call "inside-out". I might be trying to do a high block, which is a fairly simple movement of bringing the arm in towards the center line of the body, then upward, with a rotation of the arm at the end. (Hmmm... that's not the best description, but hopefully it's close enough so you get a rough idea of what I'm trying to describe.) High blocks are something we practice lots and lots of times in class and I've certainly done several hundred (perhaps thousands) of them this past year. Yet just recently in class, while doing some high block exercises I suddenly found my arm doing something that definitely wasn't a high block. At the time, I was kind of baffled by what was happening and it took me a few repetitions to get back on track. Afterwards I tried to figure out what I had been doing that was wrong and I eventually realized it was transposing two of the actions and my arm was trying to twist first, then move up. It was all happening at a subconscious level, so I wasn't really sure why it happened, but now that I'm thinking about switching letters in language (i.e. spoonerisms), I was wondering if maybe there's a corresponding thing in the physical motor-skill realm.
Unfortunately, in my brief search online, I haven't been able to find any reference to what causes spoonerisms. There are plently of web sites that list amusing spoonerims, but I failed to find anything that actually attempted to investigate the cause.