It isn't ambiguous in the slightest as it tells you not to move your fingers on the screen, so the only reasonable conclusion from this is that the direction down is from above the screen onto the surface, not laterally across the surface. And this instruction is part of the same statement, not divorced from it, so the context is perfectly clear unless you don't bother finish reading the sentence before deciding what it means.
Also, I was not meaning that the person reading was stupid, but that they were careless in their reading of the instruction, which is the sort of thing that can lead you to counting in base nine for the rest of your life, if applied to anything big and heavy that spins.
It isn't ambiguous in the slightest as it tells you not to move your fingers on the screen
Heh, and that's exactly why it's ambiguous: the first part suggests movement; and the second commands against it.
so the only reasonable conclusion from this is...
You can make an educated guess at what's intended, but you're still guessing. What if "fingers" was a typo and "finger" was written in its place? You couldn't say for certain, and that would give an entirely different "reasonable" conclusion - all based on a typo.
And this instruction is part of the same statement
And it contradicts the first part of instruction.
Also, I was not meaning that the person reading was stupid, but that they were careless in their reading of the instruction, which is the sort of thing that can lead you to counting in base nine for the rest of your life
Your concern is for my well-being is touching, but I really do take exception to your claim of careless reading being at fault. If you don't understand an instruction, sure, go back and check that you haven't missed a bit, but the best option afterwards is to seek further clarification. That's a good life rule, and I absolutely have no shame in asking when I don't understand something.
Plus, unlike guessing at "the only reasonable conclusion," I think this approach will lead to counting in base 10 for a while longer ;-)
To me, a speaker of U.S. English, "straight down" implies movement, making the instructions confusing. A non-motive indication of position would be "straight below".
I would phrase it as "press into the screen with another finger" maybe. Common screen coordinates (to me) are left/right (x), up/down (y), and in/out (z). The instruction is trying to refer to the z coord, but using the common word for the y coord.
Of course it implies movement. You have to move your finger to touch the screen. If it said straight down and had no qualifier, then it would be confusing as then down could have two common meanings. However it does have a qualifier within the same statement that makes it extremely clear that the motion described is not a motion across the screen.
Humans don't parse language the way computers do. When they see a phrase commonly associated with movement the concept of movement will enter their minds, even if a precise analysis of the sentence does not indicate movement.
Also, I was not meaning that the person reading was stupid, but that they were careless in their reading of the instruction, which is the sort of thing that can lead you to counting in base nine for the rest of your life, if applied to anything big and heavy that spins.