Synthesize and show accurately controlled visual stimuli and interact with the observer
Version: 3Matlab is a high-level interpreted language with extensive support for numerical calculations. The Psychophysics Toolbox interfaces between Matlab and the computer hardware.
Operating System: Mac OS X
The Psychtoolbox's core routines provide access to the display frame buffer and color lookup table, allow synchronization with the vertical retrace, support millisecond timing, allow access to OpenGL commands, and facilitate the collection of observer responses. Ancillary routines support common needs like color space transformations and the QUEST threshold seeking algorithm.
The Matlab & Psychtoolbox environment is flexible yet relatively easy to learn. Canned experimental programs fail because they usually can't do a really new experiment. For that you need the expressive scope of a full-fledged computer language, such as C or Matlab. Matlab is a particularly good language for running laboratory experiments.
Even for experienced programmers, three features of Matlab greatly speed the development cycle over other languages. Matlab has a rich library of high-level functions available to do math and plotting. It operates on arrays and images as named variables.
And it is interactive, so that one can type 1+1 and immediately see the answer 2, which is invaluable when developing laboratory software to run experiments.
Brand-new users who've never programmed before will find that they're learning three things when they start using the toolbox: Matlab, how to create stimuli and measure responses, and how to organize an experiment. There's almost no overlap between those three topics.
The included demos will illustrate how many common tasks may be accomplished (type help PsychDemos). To learn the language, many people say they liked the Matlab manual while others skipped the manual and learned by trial and error.
· Apple Macintosh: Psychtoolbox is developed and tested under the latest version of Mac OSX (currently 10.4.11, resp. 10.5.2). We encourage users to use the latest version of OSX ( Exception: Mac OS 10.5.3 and 10.5.4 suffer serious graphics related bugs and are not recomended! ). Generally, we have found that keeping up to date with the OS provides better performance. Intel Macs are fully supported, as explained below. Although the toolbox continues to work (for the most part) under OSX 10.3.9, we no longer test for compatibility with that OS and don't plan to fix bugs or other issues related to it.
· Windows: Psychtoolbox-3 runs under Microsoft Windows 2000 and Windows XP. Other Microsoft OSs are untested up to now. We do aim to keep the toolbox working under these versions of Windows, but this is a lower priority than OSX. As of 1. January 2008, Windows Vista is not tested for compatibility with PTB-3 by the developers, but we are aware that some people do run the toolbox under Vista and didn't receive any reports of trouble so far, so there are probably no apparent problems with it. Apart from that, there is no known benefit of running Vista over XP, so there is no reason to switch to it.
· Linux: There is also experimental support for the GNU/Linux operating system on Intel PCs in combination with Matlab 7.x or GNU/Octave 2.1.73. Due to our limited resources, we can only provide very limited support for this version. We are interested in feedback, and would welcome contributions from someone who wants to help develop this version.
· Recommended: the latest 32 bit version of Matlab (currently 7.5). PTB-3 is developed and tested for compatibility with the latest 32-bit version of Matlab. We normally only fix bugs that affect running with the current Matlab. Even so, most functions work in Matlab 6.5 and later under Mac OSX and in Matlab 5.x and later under Windows.
· Windows: Matlab version 7.4 (Release 2007a) and later are mostly supported. You may need to install some Microsoft Visual C runtime libraries to make it work, but our installer should give you instructions on how to do that if neccessary. Some old and rather obscure / obsolete MEX files that used to be bundled for Matlab releases prior to 7.4 are no longer supported - they are not really needed anymore. Matlab versions 5.1 to 7.3 should also mostly work, although use of very old Matlabs will probably cause some of our M files to abort if they make use of features only present in Matlab 7.x. This is often fixable by a bit of hacking though.
· Linux: Currently only Matlab 7.4 and GNU/Octave 2.1.73 are supported, other Matlabs of the 7.x series may work as well.
· 64-bit Matlab: Running under Matlab in 64 bit mode is not supported. But 64-bit Matlab can be run in a 32-bit mode by starting it with a command line switch: matlab.exe -win32 will start 32 bit matlab on Windows, matlab -glnx86 will start 32 bit matlab on Linux.
· Apple Quicktime: Psychtoolbox needs Quicktime 7 on OSX or Quicktime 6 or 7 on Windows for movie playback. We recommend staying up to date with the latest releases.
· For video capture support on Windows, you need to install a Quicktime video digitizer component. The free WinVDIG is known to work for USB webcams and standard consumer DV cameras with Firewire connectors and Psychtoolbox has been tested with some version of that plugin. Another (untested) option is the VDIG from AbstractPlane, which costs a small bit of money, but presumably comes with commercial support. Please note that video capture capabilities on MS-Windows are very basic and limited, probably only useable for projects with low demands.
Basic hardware requirements:
· Power-Macs: Any PowerPC based Macintosh computer capable of running Mac OSX 10.3.9 or later.
· Intel-Macs: Any Intel-based Macintosh computer. · Intel PCs: Any Intel-compatible PC that is capable of running the 32/64-bit versions of Microsoft Windows 2000/XP or GNU/Linux.
Graphics hardware requirements:
Basic Psychtoolbox functions should work on any OpenGL 1.2 capable graphics card with at least 16 MB of video ram (VRAM). Fast stimulus drawing and use of the more advanced features requires recent graphics hardware. In general you should not try to save money on the gfx-adapter, as performance of your stimulus script may depend much more on the horsepower of your gfx-adapter than on the horsepower of your cpu.