Is this squid dead or alive?
Michael at a Nadder! explains what is going on:
The salt in the soy sauce makes the tentacle neurons fire — the squid’s death does not inactivate them straight away. The first time I read the explanation I was not prepared for the effect to be so dramatic which is why I thought the squid was alive. On subsequent viewing, the soy sauce explanation seemed right. If you’re not convinced, read this news article which explains the effect and embeds the video. It also shows another video of disembodied frog legs shaking about when salted, which is a lot more convincing.
I also remember a few years ago when I was pan-frying some baby octopuses they produced a very realistic wriggling effect while being fried. It also shocked me and creeped me out a little at the time. I’ve been meaning to film the effect for a few years but I guess there’s no point now. At the time I thought this was because I soaked them in water before frying to defrost them, but it was probably because I added some sauce with salt.
Of course all of this has a wider point. The dancing octopus shows that when we make judgements about living creatures (especially about basic things such as whether it’s alive), we probably use a fairly basic brain system. We pick up on some very crude cues and extrapolate them, basically because those extrapolations make sense most of the time. (When you see such wriggling, it’s likely to be something alive.)
UPDATE: I should have known PZ would have seen it already. Here’s what he said:
This video may not be to everyone’s taste — it’s pretty awful. This is an octopus dish served in Hakodate, in which the poor raw cephalopod is presumably dead, but when soy sauce is poured over it, it’s triggered to writhe its tentacles.
I do not approve. Either it’s cephalopod torture if it’s still alive, or soy sauce is the secret ingredient for zombie reanimation*. And then…no one eats zombies. That’s just disgusting.
And further down in the comments:
I read a couple of the links to the preparation of this atrocity, and I suspect the octopus is not dead. That’s not its head that is lopped off; that’s the visceral mass, so that’s more like a disemboweling. The relevant ganglia are going to be at the base of the tentacles.
Thanks to sg in the comments for the find. I admit I’m a little astonished how fast that was that someone who remembered PZ’s thread on the topic and his buried follow up comment showed up.
Quite frequently I am amazed in blogging how quickly someone with a key point of knowledge on a subject I’m writing on will appear. It indicates the audience is always wider than one imagines.