If you use this software, please cite one of the papers that describe it.
- Peirce, JW (2007) PsychoPy - Psychophysics software in Python. J Neurosci Methods, 162(1-2):8-13
- Peirce JW (2009) Generating stimuli for neuroscience using PsychoPy. Front. Neuroinform. 2:10. doi:10.3389/neuro.11.010.2008
Citing these papers gives the reviewer/reader of your study information about how the system works, it also attributes some credit for its original creation, and it means provides a way to justify the continued development of the package.