Frequently asked questions

Installation with pip is failing

Certain packages, such as numpy, scipy, pandas, and pymvpa, need to be compiled when installing via pip, and that process commonly fails. If you find yourself in this situation (maybe you tried to pip-install seaborn but didn’t have pandas on which it depends), try installing the packages that pip failed to install manually by downloading required packages as listed in (Get psychopy_ext).

Still no luck? Okay, you don’t have PsychoPy and don’t know how to install it because it has a million dependencies? Welcome to the batteries included Python. There is no simple solution but try following this tutorial on the many options you have.

Where do I find demo files?

Demos are located in the psychopy_ext/demos folder in your Python’s site-packages (unless you are using virtualenv in which case you know where you put psychopy_ext). Don’t know where site-packages are? Try:

import site; print site.getsitepackages()

Can’t find it still? Fine, just download the psychopy_ext zip file then from the PyPI index. The demos are in the psychopy_ext folder.

How do I run demos?

Windows: double-click run.bat (instead of


  • find the Terminal (also try Ctrl+Alt+T)
  • navigate to the folder containing demos
  • type python

Why can’t I run fMRI demo?

There are a few possible problems:

  1. You are too impatient! Loading the fMRI demos take a while, don’t force close the program.
  2. You don’t have pymvpa2 or nibabel installed, so follow installation instructions carefully Get psychopy_ext.
  3. The fmri module is still in development so maybe you stumbled across a bug. Let me know!

How / where do I write my own scripts?

If you are a Standalone PsychoPy user, an editor is built-in (go to View > Go to Coder view). However, it is very basic and thus better options are recommended below:

  • Notepad++: like the default Notepad, but on steroids
  • NinjaIDE: a beautiful and convenient IDE dedicated to Python
  • Geany: a powerful lightweight cross-platform IDE
  • Spyder: looks like MatLab
  • Canopy: beginner-friendly but you may have to register for it (still free)

In the source code, why are some variables in camelBack, and others just lower_case?

When you see camelBack, it’s probably a function or a variable from PsychoPy. However, psychopy_ext follows PEP 8 naming conventions, and you should too.