DownloadPsychtoolbox([targetdirectory][, flavor][, targetRevision][, downloadmethod][, tryNonInteractiveSetup=0])


Due to the lack of financial support for Psychtoolbox by the vast
majority of our non-paying users, we did not and currently do not have
the funding to work on a good alternative solution for this. Therefore
this convenient installation and update method will be unavailable for an
unknown period of time.

See for a
workable, although way less convenient and advanced, download and
installation method, via zip file download and execution of
SetupPsychtoolbox(). Good luck!


This script downloads the latest GNU/Linux, MS-Windows, or Apple macOS
Psychtoolbox-3, version 3.0.10 or later, from our git-server to your
disk, creating your working copy, ready to use as a new toolbox in your
MATLAB/OCTAVE application. Subject to your permission, any old
installation of the Psychtoolbox is first removed. It’s a careful
program, checking for all required resources and privileges before it

Note: If you use a Debian derived Linux distribution, e.g., Debian or
Ubuntu, consider installing the package octave-psychtoolbox-3 or
matlab-psychtoolbox-3 instead from - This is more
convenient and will provide you with automatic updates.

CAUTION: Psychtoolbox 3.0.14 will not work anymore with OSX versions
earlier than 10.11 “El Capitan”.

CAUTION: Psychtoolbox 3.0.13 will not work anymore with 32-Bit Octave-4
on MS-Windows, or with OSX versions earlier than 10.10 “Yosemite”.
Psychtoolbox will likely work with versions of Microsoft Windows older
than Windows-10, but it is not tested on such systems anymore and not
supported at all on Windows versions earlier than Windows-7. For best
compatibility you should probably use Windows-10 with all upgrades

CAUTION: Psychtoolbox 3.0.12 will not work anymore with 32-Bit Matlab, or
with OSX versions earlier than 10.8 “Mountain Lion”. Psychtoolbox may
work with versions of Microsoft Windows older than Windows-7, but it is
not tested or supported on such ancient Windows systems anymore, so use
at your own risk.

Psychtoolbox 3.0.11 *will not work* with GNU/Octave on MS-Windows, or
with 32-Bit Octave on OSX, as support for these setups has been cancelled
for the 3.0.10 series. It will also not work with 32-Bit Matlab on OSX,
or with OSX versions earlier than 10.6.8 “Snow Leopard”, unless you
choose the unsupported legacy flavor “Psychtoolbox-3.0.10” via the
optional ‘flavor’ parameter.

If you want to download older versions of Psychtoolbox than 3.0.10, e.g.,
version 3.0.9, use the DownloadLegacyPsychtoolbox() function instead of
this function.

On Mac OSX, all parameters are optional. On MS-Windows and GNU/Linux, the
first parameter “targetdirectory” with the path to the installation
target directory is required. The “targetdirectory” name may not contain
any white space, otherwise download may fail with mysterious error

On OSX, your working copy of the Psychtoolbox will be placed in either
your /Applications or your /Users/Shared folder (depending on permissions
and your preference), or you may specify a ‘targetdirectory’, as you

On Microsoft Windows, you must specify the full path, including
the drive name where Psychtoolbox should be installed, e.g.,

The desired flavor of a Psychtoolbox release can be selected via the
optional “flavor” parameter: By default, ‘beta’ (aka ‘current’) will be
installed if you don’t specify otherwise, as this is almost always the
best possible choice. You may be able to download an old versioned
release via a namestring like ‘Psychtoolbox-x.y.z’, e.g.,
‘Psychtoolbox-3.0.14’ if you’d want to download version 3.0.14. This is
only useful if you run a very old operating system or Matlab version that
isn’t supported by the current “beta” anymore, so you’d need to stick
with an old versioned release.

Normally your download should just work(TM). Very infrequently, the
download servers may be overloaded or down for maintenance, resulting in
download failure. In that case, please retry a few hours later.

The “targetRevision” argument is optional and should be normally omitted.
Normal behaviour is to download the latest revision of Psychtoolbox. If
you provide a specific targetRevision, e.g., 1234 for revision 1234, then
this script will install a copy of Psychtoolbox according to the
specified revision.

This is only useful if you experience problems and want to revert to an
earlier known-to-be-good release.

Revisions can be specified by a revision number or by the special flag
‘PREV’ which will choose the revision before the most current one.

‘downloadmethod’ Optional: The method to use or prefer for download. By
default method 0 is used, which means to perform a Subversion checkout of
a fully versioned working copy, including all revision information, which
allows to go backward in time or update efficiently via the
UpdatePsychtoolbox() command, query the current version and revision of
Psychtoolbox via PsychtoolboxVersion() command, and access the
development history via svn command-line tools etc. A setting of 1
requests an export without versioning information, essentialy a dumb
download. This will cut download size and disc space usage in less than
half, but you won’t be able to use UpdatePsychtoolbox() or
PsychtoolboxVersion() or other svn features anymore.

By default, the most efficient and convenient method of Subversion
download is used, e.g., using Matlabs integrated SVNKit for Matlab R2014b
or later, instead of a svn command-line client. You can always enforce
use of an installed svn command-line client via setting downloadmethod to
-1. This is the old way of doing things, in case the improved method via
SVNKit should not work for some reason.

The optional parameter ‘tryNonInteractiveSetup’ if provided as 1 (true), will
try a setup without user interaction, not asking users for input in certain
situations, but assuming an answer that keeps the setup progressing. Note that
this is not guaranteed to work in all cases, and may end in data loss, e.g.,
overwriting an old and potentially user-modified Psychtoolbox installation.
This non-interactice setup mode is highly experimental, not well tested, not
supported in case of any trouble!

INSTALLATION INSTRUCTIONS: The Wiki contains much more up to date
instructions. If in doubt, follow instructions on the Wiki!

  1. If you are using Matlab R2014b or later, skip to step 2.

  2. On older Matlab versions, or on Octave, if you don’t already have it,
    you must install a Subversion client.

On Linux, use the OS package manager, e.g., on Debian/Ubuntu based

sudo apt install subversion

On Windows, download the Windows Subversion client from the internet, e.g.,
from one of these:

On macOS, if you happen to have HomeBrew ( installed, a

brew install subversion

should do the trick.

After installation of the Subversion client, you will need to exit and
restart Matlab or Octave, so it can find the new subversion executable.

Btw. you should avoid to install the client into a path that contains
blanks/spaces/white-space as this can lead to download failures in some
cases, e.g., ‘C:\Program Files...’ may be bad because there is a blank
between the “Program” and “Files”.

Alternatively, if you don’t have the neccessary permissions to install
Subversion into a system folder, you can install Subversion into an
arbitrary folder on your system (excluding ones with blanks in their
path) and then add that folder to your Matlab or Octave path. E.g. you
installed into D:[MyOwnFolder](MyOwnFolder)\Subversion\ . Then you can do this:
addpath(‘D:[MyOwnFolder](MyOwnFolder)\Subversion'). Our installer should find the
client then.

  1. On macOS, to install the Psychtoolbox in the default location
    (/Applications or, failing that, /Users/Shared). Just type:


Our standard option is in the Applications folder, but note that, as with
installation of any software, you’ll need administrator privileges. Also
note that if you put the toolbox in the Applications folder, you’ll need
to reinstall it when MATLAB / OCTAVE is updated on your machine. If you
must install without access to an administrator, we offer the option of
installing into the /Users/Shared/ folder instead. If you want to install
the Psychtoolbox in some other folder, then specify it in the optional
first argument of your call.

On Windows or Linux, provide a pathname, e.g.:

That’s it. Any pre-existing installation of the Psychtoolbox will be
removed (if you approve). The program will then download the latest
Psychtoolbox and update your MATLAB / OCTAVE path and other relevant
system settings.

Enjoy! If you’re new to this, you might start by typing “help

P.S. If you get stuck, first check the FAQ section and Download section
of our Wiki at If that doesn’t help, post
your question to the forum:

Please specify your full name and the version of your operating system,
MATLAB / OCTAVE, and psychtoolbox.


To upgrade your copy of Psychtoolbox, at any time, to incorporate the
latest bug fixes, enhancements, and new features, just type:

UpdatePsychtoolbox cannot change the flavor of your Psychtoolbox. To
change the flavor, run DownloadPsychtoolbox to completely discard your
old installation and get a fresh copy with the requested flavor. If you
used DownloadPsychtoolbox with the optional ‘downloadmethod’ set to 1
then UpdatePsychtoolbox() won’t work. That’s the price you pay for saving
disc space.


There’s a thorny issue with permissions on OS/X. It may not be possible
to install into /Applications (or whatever the targetdirectory is) with
the user’s existing privileges. The normal situation on Mac OSX is that a
few users have “administrator” privileges, and many don’t. By default,
writing to the /Applications folder requires administrator privileges.

DownloadPsychtoolbox creates the Psychtoolbox folder with permissions set
to allow writing by everyone. Our hope is that this will allow updating
(by UpdatePsychtoolbox)) without need for administrator privileges.

Some labs that may want to be able to install without access to an
administrator. For them we offer the fall back of installing Psychtoolbox
in /Users/Shared/, instead of /Applications/, because, by default,
/Users/Shared/ is writeable by all users.


Normally all users of MATLAB / OCTAVE use the same path. This path is
normally saved in MATLABROOT/toolbox/local/pathdef.m, where “MATLABROOT”
stands for the result returned by running that function in MATLAB, e.g.
‘/Applications/’. Since pathdef.m is inside
the MATLAB package, which is normally in the Applications folder,
ordinary users (not administrators) cannot write to pathdef.m. They’ll
get an error message whenever they try to save the path, e.g. by typing
“savepath”. Most users will find this an unacceptable limitation. The
solution is very simple, ask an administrator to use File Get Info to set
the pathdef.m file permissions to allow write by everyone. This needs to
be done only once, after installing MATLAB.


Path   Retrieve current version from GitHub | View changelog