ME:
    > Human perception tests show, that a small, high contrast, pixelated image
    > demands more attention than smoother, antialiased one.
   
    ALEXANDRE:
    > URL?
   
Hi, and sorry for the delay. A little busy at the moment.
Now, about those tool cursor icons... The display density is getting higher, and this jagged-vs-smooth issue will be obsolete. On those cool smartphones with crazy pixel density a single pixel is so small that all 'the 'jaggies' are gone + all the contrast preserved. That's great! The technology finally caught up with our eyes. ;)
Even then, we will need a better way of displaying the icons or they'll shrink together with the pixel size. Yes, we could use bigger pixels for conservatives out there, :) but scalable cursor icons seem more sensible. And somehow svg popped up as an option… The current bitmapped tool cursor icons served great so far. I don't want to sound as I would like them removed, but to suggest an update.

As for the URL Alexandre asked for, well, I feel silly sending this, and not some killer-website that would give you an exact answer. But, please if you have some time, give it a read. ;) I have prepared the links for you, and some reasons, I think, support scalable tool cursors.

1. "Choosing Binary or Grayscale Bitmaps: some Consequences for Users"
(Alison Black, Andrew Boag)
On an example of typeface recognition (not readability!), this paper shows that binary bitmaps are less effective.
link: opensourcebydesign.org/inkscape-concepts/bingrey.pdf

2. "A Psychophysical Approach to Assessing the Quality of Antialiased Images"
(James A. Ferwerda, Donald P. Greenberg from Cornell Uni)
Some experiments on the benefits of antialiasing, especially when the image is moving.
link: opensourcebydesign.org/inkscape-concepts/aaimages.pdf

3. "Spatial-frequency tuning of visual contour integration"
(S. C. Dakin and R. F. Hess)
A paper on how problems of contour recognition and integration. Based more on the hard-wiring of the brain.
link: opensourcebydesign.org/inkscape-concepts/contourintegration.pdf

*If you somehow get interested in this stuff, a book 'Psychophysics: A Practical Introduction ' by Prins and Kingdom, is a good starter.

4. http://en.wikipedia.org/wiki/Ecological_validity_%28perception%29, perception theory... In short, The brain recognizes images better if they display more of the characteristics of the real object. Since a blocky, jagged edged pencils are not what brain is used to seeing in the nature, such a pixelated image of a pencil has to be processed more by the brain to 'connect-the-dots' and figure out 'Oh it's a pencil!'. Of course, when creating an image of a pencil we should carefully balance the realism with purpose and function.

5. Inkscape already displays AA graphics and has AA icons in the toolbar. I believe the reasons for this are the same. Also there an entry in Inkscape Wiki stating 'scalable icons' as one of the design goals. http://wiki.inkscape.org/wiki/index.php/Icons

6. Personal experience. I have prepared a small and clumsy rendition of the pencil tool cursor for illustration. I admit, it's not doing justice to the bitmap icon, but I hope it's ok. link: opensourcebydesign.org/inkscape-concepts/bitmap-vector comparision.svg

Cheers,

I will try to provide answers for other questions you asked me, too.

Alex