> I mean, feeling sand compress in subtle ways and being able to map that mentally to an object that might be hidden in the sand seems like literally touch plus normal world modelling / reasoning

That seems like a very strong claim against the paper’s results. What makes you think that the study participants located the cube with reasoning, rather than unthinking sense?

I think we can be too quick to write things off as somehow coming from conscious thought when they bypass that part of our minds entirely. I don’t form sentences with a rational use of grammar. I don’t determine how heavy something is by reasoning about its weight before I pick it up. There is something much more interesting happening cognitively in these cases that we shouldn’t dismiss.

what is "unthinking sense?" we model the world subconsciously

'normal world modelling' doesn't imply conscious thought to me. Humans do a ton of stuff unconsciously e.g. 'gut instinct'.