DownloadPsychtoolbox([targetdirectory][, flavor][, targetRevision])

This script downloads the latest GNU/Linux, Mac OSX, or MS-Windows
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 will 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-3.0.7’ if you’d want to download version 3.0.7. 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, 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.

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

  1. If you don’t already have it, you must install the Subversion client.
    For Mac OSX 10.6 and later, download the latest Mac OSX Subversion client
    If you have the XCode command line tools installed, you won’t need to
    install subversion as it is included in these tools.

For Windows, download the Windows Subversion client from one of these:

Install the Subversion client on your machine by double-clicking the
installer and following the instructions. After installation of the
Subversion client, you will need to exit and restart Matlab or Octave, so
it can find the new subversion executable. In many cases it may be
neccessary to even reboot your computer after installation of subversion.
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.

For Linux, just install the subversion package from your package
management tool.

  1. On MacOS/X, 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 must 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.


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