A PsychoPy (Pierce, 2007) version of STOP-IT. The software is still in the beta phase, and has not been properly tested yet. Extra documentation and an analysis program will also be added at a later stage
In this version of the stop-signal task, subjects have to respond to the direction of a green arrow. However, they have to withhold their response when the arrow turns red after a variable delay. The stop-signal delay is constantly adjusted using a staircase tracking procedure.
The experiment starts with a short practice block (with immediate feedback), followed by three (default) experimental blocks.
To install PsychoPy, see: http://www.psychopy.org
After PsychoPy is installed, 'STOPIT.py' can be opened in the PsychoPy Coder. When you click on the 'Run' button, the program will start. You can stop the experiment by pressing the 'esc' key (but this works only when a stimulus is on the screen).
To change size of stimuli, number of blocks, timing, etc., the PsychoPy code can be changed in the PsychoPy coder.
To change the instructions, open the 'STOPIT_instructions.txt' in a text editor and made the required changes. (Do not forget to save the file!)
Any comments or suggestions are welcomed!
Peirce, JW (2007) PsychoPy - Psychophysics software in Python. J Neurosci Methods, 162(1-2):8-13