Additional Software Contributed by Users:

VCRDM - Variable Coherence Random Dot Motion

Vcrdm download is a library of code for creating variable coherence random dot motion for visual experiments for use on OS X macs using the latest Psychtoolbox software. It is based on the dots patches originally created by Tony Movshon, and was created by Maria Mckinley, who currently works in the lab of Michael Shadlen. This software has been tested fairly extensively at this point, but please be sure to contact me if you find a bug or have questions. It is pretty well documented. It includes software for making the dot patches and targets, as well as a full experiment procedure for a keypress motion discrimination task. The software for creating the dot stimuli on OS 9 macs can be found here. Please send questions or comments about the software to Maria: parody @ Thank you and Enjoy!

PTB tutorial @ Silver lab - University of California, Berkeley

Created by Ariel Rokem, based on a tutorial/class/book made by Ione Fine

Take color calibration readings with a ColorVision Datacolor Spyder2 (low cost USB colorimeter for CRT/LCD)

-download (file is called "" -- must be a member and logged in to the psychtoolbox yahoo forum)
-currently includes (and depends on) spyder2 SDK (not compatible with spyder3), but SDK files may be removed soon. ColorVision asked me not to share them publically, though their policy was at least at one point to make them available for educational institutions. see this forum message
-readings in CIE 1931
-sample output (file is called "spyder.png" -- must be a member and logged in to the psychtoolbox yahoo forum)
-uses matlab's loadlibrary() to access c functions in the Spyder API. SDK available from Dana Gregory (,
-tested on winXP (2007b,2008a), and intel OSX 10.4.11 (2007a)
-must install the spyder2 driver and software, in my experience, you must run their software at least once to enable the driver.
-contributed by erik flister, ucsd, 2008 (, code may be shared/modified as long as my name travels with it.
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