Expyriment is an open-source and platform independent light-weight Python library for designing and conducting timing-critical behavioural and neuroimaging experiments. The major goal is to provide a well-structured Python library for a script-based experiment development with a high priority on the readability of the resulting programme code. It has been tested extensively under Linux and Windows.

Expyriment is an all-in-one solution, as it handles the stimulus presentation, recording of I/O events, communication with other devices and the collection and preprocessing of data. It offers furthermore a hierarchical design structure, which allows an intuitive transition from the experimental design to a running programme. It is therefore also suited for students as well as experimental psychologists and neuroscientists with little programming experience.

Website: http://www.expyriment.org


Main features

  • Easy syntax, very readable (due to Python)
  • Cross-platform (Linux, Windows, OS X)
  • Allows for fast and efficient programming of experiments (do more with less code)
  • A variety of standard stimuli (Text, Picture, Audio, Video etc.)
  • Keyboard, Mouse, Serial Port, Parallel Port and Gamepad support
  • Hierarchical structure of experimental units (Experiment, Blocks, Trials, Stimuli)

For a full documentation of all Expyriment functionality (i.e. all available modules, classes, methods, functions, constants, and attributes provided by the Expyriment Python package), please have a look at the API reference pages

Example code

Creating experiments, blocks, trials and stimuli:

exp = expyriment.design.Experiment()
block = expyriment.design.Block()
trial = expyriment.design.Trial()
stimulus = expyriment.stimuli.TextLine(text="Hello World")

Building a hierarchy between various structures:


Presenting stimuli:

for block in exp.blocks:
    for trial in block.trials:

Handling input devices:

button, rt = exp.keyboard.wait([expyriment.misc.constants.K_SPACE])

Logging data:

exp.data.add([button, rt])


Expyriment is free software and released under the Open Source GNU General Public Licence of Free Software Foundation.


The Expyriment repository is currently hosted on Google Code. Get a local copy of this repository with this command:

hg clone https://code.google.com/p/expyriment/

Mailing lists

Expyriment newletter: All users of Expyriment should subscribe to the Expyriment newsletter, since the project is still under development. All modifications and new versions will be announce via this mailing list. (visit website or send an email to expyriment+subscribe@googlegroups.com)

Expyriment users mailing list: If you have questions regarding the installation, usage or documentation of Expyriment please don’t hesitate to contact the Expyriment users mailing list (visit website or send an email to expyriment-users+subscribe@googlegroups.com) or contact us directly by sending an email to info@expyriment.org.

Suggestions and bug tracking

If you want to make suggestions to improve Expyriment or you found a bug, please post your comments to the Expyriment issues page or contact us directly by sending an email to info@expyriment.org.

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