Thanks, Kaj—I think this is a good thing to be cautious of in general. In this case I’m happy to send Duncan my thoughts, but am planning to do so privately, since I feel like that creates less incentive for other people to be like “ooh, do me!” in the hopes of getting public praise.
(I’m happy to try sending thoughts to anyone I know who wants them, though I think in plenty of cases it’ll just be “I don’t notice anything particularly remarkable about you on this axis”.)
Yes, I do think there are body-language indicators that are more about status than size, though I definitely agree with alkjash below that the two things are entangled. I agree that Keith Johnstone in Impro is often talking about size, though I think he’s conflating it with status, so often talks about both in one breath.
At a first pass, I think the clearest body-language-related thing that’s about status rather than size is basically just how comfortable you seem, vs. intimidated/discomfited. So I agree with your suggestions—talking too quickly and fidgeting both seem like they signal discomfort.
Some examples where I think Impro gets this right, from skimming through my copy quickly:
In contrast to one teacher who was strict and terrifying, and one teacher who was weak and ridiculed, Johnstone talks about a teacher of his who was “upright, but relaxed”—I like that as a description of high/small. (he then goes on to describe him as “a status expert, raising and lowering his status with great skill”, which I think should be “a size expert, making himself bigger and smaller with great skill.”)
Johnstone describes a game he plays with his students where, without telling them, he starts inserting “er” (British for “um”) at the start of all his sentences, and asks them if they notice any change. I think this is an example of something that makes you come across as less comfortable with the situation and therefore lower status. (Though there are lots of ways to say “um”, so this probably isn’t true as a blanket statement.)
Facial expression and apparent relaxed-ness are probably the most concrete I can get at a first pass. Does that help / thoughts?