# Help with stop-signal reaction time task

**URL:** <https://discourse.psychopy.org/t/help-with-stop-signal-reaction-time-task/45569>\
**Category:** Builder\
**Created:** [September 10, 2025, 2:04pm UTC](https://discourse.psychopy.org/t/help-with-stop-signal-reaction-time-task/45569 "2025-09-10T14:04:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![daisy.s](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@daisy.s](https://discourse.psychopy.org/u/daisy.s)\
**Post date:** [September 10, 2025, 2:04pm UTC](https://discourse.psychopy.org/t/help-with-stop-signal-reaction-time-task/45569/1 "2025-09-10T14:04:03Z")

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**OS** (e.g. Win10): Win10  
**PsychoPy version** (e.g. 2024.2.4 Py 3.8): PsychoPy 2025 1.1

**What are you trying to achieve?:**

I am attempting to create a stop-signal reaction time task in PsychoPy Builder, but I am new to the software and have a few things I can’t figure out how to do. I haven’t been able to find any explanations for these online or on this forum, but if anyone knows of one, please let me know.

- how do I make a loop continue endlessly, until participants press the correct button 10 times in a row?
- how do I randomise when a sound stimuli will occur? (i.e., in the main task, some trialsill include a ‘beep’ and others will not). And following on from this, how do I change the keyboard response that is stored as ‘correct’ for these trials with sound to be no key press?
- How do I randomise the colour of the polygon stimulus? I know how to randomise images, and am using images of circles as a placeholder at the moment, but cannot work out how to randomise the colour of the polygon stimuli themselves.

Sorry for all the questions, I am finding it difficult to find any answers to these elsewhere! Unfortunately I don’t know enough Python to use the coder option, so advice about Builder would be ideal. Any help is much appreciated.

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**Author:** ![JensBoelte](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/jensboelte/32/9060_2.png) [@JensBoelte](https://discourse.psychopy.org/u/JensBoelte)\
**Post date:** [September 11, 2025, 9:14am UTC](https://discourse.psychopy.org/t/help-with-stop-signal-reaction-time-task/45569/2 "2025-09-11T09:14:15Z")

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Hello @daisy.s

I think it would be best to read Building Experiments in PsychoPy, see here [Resources for teaching and learning — PsychoPy v2025.2.1](https://www.psychopy.org/teaching/index.html). You will find the answers to all your questions there, and more besides.

Best wishes Jens

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**Author:** ![daisy.s](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@daisy.s](https://discourse.psychopy.org/u/daisy.s)\
**Post date:** [September 15, 2025, 12:11pm UTC](https://discourse.psychopy.org/t/help-with-stop-signal-reaction-time-task/45569/3 "2025-09-15T12:11:22Z")

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Hi Jens,

Thank you, I wasn’t aware of this book! I’ll definitely take a look.