Psychtoolbox interfaces between Matlab or Octave and the computer hardware. The PTB core routines provide high performance 2D and 3D graphics with the highest color and luminance precision, timing precision and control. This both on standard displays, as well as with special visual stimulators, and with High Dynamic Range displays, and with a wide variety of Virtual/Augmented Reality devices. They expose raw OpenGL commands, support video playback and capture, as well as low-latency precisely timed audio playback and capture. They facilitate the collection of observer responses with high timing precision via various input modalities like keyboard, mouse, game controllers, multi-touch touch screens, response boxes, gaze trackers, and digital / analog i/o equipment. Ancillary helper routines support common needs like color space transformations, calibration, and psychometric procedures like, e.g., the QUEST threshold seeking algorithm and others.

Various 3rd party frameworks and higher level toolboxes are built on top of Psychtoolbox to make implementation of research data collection especially easy in specific sub-domains of neuroscience. For beginners or certain domains there also exist user friendly 3rd party graphical user interfaces, e.g., PsyBuilder.

You can also run some of your Psychtoolbox studies online, via VPixx Labmaestro service under

Psychtoolbox has many active users, an active forum, and is widely cited. The current version supports at least Matlab R2023b on Linux, Windows and macOS, and Octave 5 and later on Linux, Octave 7.3 on Windows, and Octave 8 on macOS.

Psychtoolbox News

Psychtoolbox updated


Psychtoolbox 3.0.19 update “Scraps” was released at 5th June 2024. As usual, the complete development history can be found in our GitHub repository. The release tag is “”, with the full tree and commit logs under the URL:

Some of this Psychtoolbox release was sponsored by Mathworks under the year 2023/2024 contract..

Compatibility changes wrt. Psychtoolbox

  • None.


  • None. Just some small fixups for improved Ubuntu 24.04-LTS and Matlab R2024a compatibility.



  • Psychtoolbox was built and tested against Matlab R2024a.

  • PsychLinuxConfiguration: Quote paths, to improve MLTBX compatibility.

  • PsychLinuxConfiguration(): Add users also to ‘gamemode’ group. This provides additional permissions to the gamemoded running on behalf of the user, to execute additional performance optimizations as part of Priority(n) with n > 0. Needed on at least Ubuntu 24.04-LTS and later.

  • Screen('OpenMovie'): On Linux, use pipewiresink as audio sink if available. Should fix the following issue on Ubuntu 24.04-LTS and later, and other distributions that use Pipewire as desktop sound server and have an outdated buggy Pulseaudio 16 installation, instead of the more recent Pulseaudio 17. The bug can’t be fixed on Ubuntu 22.04-LTS without manual user workarounds. See following issue for this bug, which is likely not encountered often:

    On unfixed affected systems (mostly Ubuntu 22.04-LTS), if there is a notable time delay between Screen('OpenMovie') and start of video+audio playback via Screen('PlayMovie'), then the movie playback will freeze after displaying the 1st video frame for the duration of that delay between OpenMovie and PlayMovie, then continue. Problem didn’t exist in earler Linux distributions like Ubuntu 20.04-LTS and is fixed by this bug fix for later distros like Ubuntu 24.04-LTS from April 2024.


  • Psychtoolbox was built and lightly tested against Matlab R2023b.


  • Psychtoolbox was built against Matlab R2023b and tested against Matlab R2024a and Octave 8.4 from HomeBrew. It also works on the new Octave 9.1 from HomeBrew

  • SetupPsychtoolbox: Quote paths, to improve MLTBX compatibility.

  • TextInOffscreenWindowTest.m: Fix it for Retina displays on macOS. Also cleanup.

  • BitsPlusPlus: Handle Apple macOS Retina displays properly for imaging pipeline validation runs.

  • ImagingStereoDemo: Handle Apple Retina displays properly during movie writing.

  • TwoStateQuery(): Add workaround for broken Matlab R2024a on Apple macOS.


Celia's VSS 2024 presentation available on YouTube.


Celia’s Psychtoolbox 2024 update presentation from last Monday at VSS 2024 is now available on YouTube in Celia’s channel. It was part of the satellite event about “Psychophysics Software with Matlab”, organized by Mathworks with support from INCF.

This year, Mathworks chose a title for the satellite that attracted an audience bigger than the 8 or so people that showed up last time, estimates from people in the room suggest about 50 participants.

The new presentation is here:

Commenting, questions etc. wrt. to the presentation should probably be directed at the user forum here:

I don’t know when the rest of the presentations, e.g., from PsychBench and VPixx and INCF and Mathworks, as well as the Q & A, will become available, as that is done by Mathworks or INCF.

For reference, Celia’s past presentation from VSS 2022 can be watched here:


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