[rikf]

I find it annoying when I have to move my hands from the keyboard to the mouse. I imagine it would be infinitely more irritating and far less comfortable moving my hands from the keyboard to touch a vertical screen in front of me.

[bryanlarsen]

A large part of the reason why that's so annoying is that when you do that you have to also figure out where the mouse pointer is, and then start the mouse moving in the right direction. Once the mouse is moving the interaction is very natural and you can do it by auto-pilot. But until it is, you actually have to use a little piece of your brain which you'd rather focus on the problem at hand.

Touch should completely negate that. Just touch what you're looking at; you should be able to do that without requiring any higher brain activity.

[hollerith]

>you have to also figure out where the mouse pointer is, and then start the mouse moving in the right direction

Although it can be tricky to know what is actually going on during a "non-deliberative" task, I am fairly sure I start moving the mouse, then my brain's motion-detection circuitry very naturally tells me where the cursor is.

One of the reasons I believe that is that I remember a few times choosing (or noticing that I prefer) to make a vaguely semicircular arc rather than abruptly reversing direction. (If I did what you describe, I would probably not have reversed direction often enough to have such memories. In contrast, if I'm right, then I would've reversed direction half of the times that I had no idea initially where the cursor was relative to the target.)

[rikf]

I dont think its really the cognitive effort that I find annoying but rather the time it actually takes to move my hands from the keyboard to the mouse.

I am firmly in the know thy shortcuts camp and find anything that forces me to move hands away from the keyboard has a negative effect in terms of my productivity. With a mouse and keyboard at least your hands are moving in the same plane.