Readability and familiarity are not the same but closely related. There is nothing inherently more or less readable in the rust or haskell tree example.
I think there is work on "readability", just in another context: Its called typography and orthography. And I think the gist of it is: Do it like everybody else does, first and foremost, strange and unfamiliar equals unreadable.
> I think there is work on "readability", just in another context: Its called typography and orthography.
I think that's a very different case. Maybe some analogies might be drawn between some of that work and some of the lower-level aspects of reading code (related to syntax noise etc), but code readability, if it's a defensible concept at all, is a far more complex and layered phenomenon than letter & word recognition.
The first thing a researcher would need to establish is whether or not readability even exists as a natural kind apart from familiarity. I don't know the field, so this might already have been pursued somewhere.
I think there is work on "readability", just in another context: Its called typography and orthography. And I think the gist of it is: Do it like everybody else does, first and foremost, strange and unfamiliar equals unreadable.