PsychoPy® is an open-source package for running experiments in Python (a real and free alternative to Matlab). PsychoPy® combines the graphical strengths of OpenGL with simple Python syntax to give scientists a free and simple stimulus presentation and control package. It is used by many labs worldwide for psychophysics, cognitive neuroscience and experimental psychology.

You can now use PsychoPy® to run studies online! Thanks to it’s Javascript sister library PsychoJS the easiest way to launch studies online from PsychoPy® is using Pavlovia®. You can see the large number of institutes using Pavlovia® for their research on the Pavlovia Licensees page.


There are many advantages to using PsychoPy®, but here are some of the key ones

  • Simple install process (a standalone environment)

  • A wide variety of learning resources

  • An active user forum for help and support

  • Precise timing (Bridges et al., 2021)

  • Builder interface to guide experiment creation with minimal coding

  • Coder interface for those that like to program from scratch (see Code Component for the best of both worlds! Make experiments quickly using Builder and add code snippets for maximum flexibility)

  • take experiments online with Pavlovia.org (see Running and sharing studies online)

  • Platform independent - run the same script on Win, macOS or Linux

  • Flexible stimulus units (degrees, cm, or pixels)

  • Wide variety of stimuli (images, text, gratings, random dots, noise, movies, sounds)

  • Input from keyboard, mouse, microphone or button boxes

  • Compatible with a range of hardware (EEG, Eyetracking, fMRI, Spectrascan, Minolta, Cambridge Research Systems Bits++, Cedrus response boxes (RB7xx series))

  • Multi-monitor support

  • Automated monitor calibration (for supported photometers)

A sustainable open-source model

Open-source and Open Science is at the heart of our community. Because PsychoPy® is open source, you can download it and modify the package if you don’t like it. And if you make changes that others might use then please consider giving them back to the community via the github page. PsychoPy® has been written and provided to you absolutely for free and it is thanks to a large number of dedicated contributors that is can keep getting better and better - so please do contribute!

As PsychoPy® grew in popularity, it became clear that developing it “as a side project” in researchers spare time was not going to be sustainable. Pavlovia.org provides a revenue to sustain ongoing development. We have been very careful with our pricing to ensure a cost that is as accessible as possible whilst still providing sufficient revenue to keep developing professional tools. The aim is that we can keep developing great research software, that is still free for most users (you can still run your study offline and share your experiment with other researchers using Pavlovia® for free), but now we have funding support to employ full-time staff to work on it!

System requirements

Although PsychoPy® runs on a wide variety of hardware, and on Windows, macOS or Linux, it really does benefit from a decent graphics card. Get an ATI or nVidia card that supports OpenGL 2.0. Avoid built-in Intel graphics chips (e.g. GMA 950)

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