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QUEST+ implementation

Hi all,
I’m trying to use the quest+ implementation that seems to be coded in Psychopy3. Quest method is well documented and I was able to set up an experiment, but it seems that there is no info about the parameters needed to run the quest+. Does anybody know how to use this method?
Thank you very much!!!

Hello @mvustarroz, I’m the author of the QUEST+ implementation. The documentation should be updated with the next release of PsychoPy (which should happen soon-ish if I’m not mistaken, as @jon has just published a second release candidate).

Are you trying to use QUEST+ via code or via the Builder?

Hi Richard, thank you so much for the quick response. I’m working via code, so I’d just need some help about how to set the parameters of the function.

Looking forward for your responses and updates!!



Hey @mvustarroz, I just checked the sources of PsychoPy 3.2, and the docstrings of the QuestPlusHandler class are fairly complete I believe:

If you could tell me about your intended experiment (which stimuli / intensities you are planning to use, which task participants are to perform, how many trials to run, …), we could try to work out a parameter set that should get you started!

I’ve just pushed the updated docs (thanks Richard) to

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Thanks @jon!

Thank you so much for you both (and sorry for the late response)
Now I’m working with the QUEST+ implementation and I’ll be back here in case I need more assistance. ( BTW: I’m interested in exploring how different fonts are perceived. I’m sure I’ll be back soon!)


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Dear Richard, I’m back to you because I’ve been trying to use the QUEST+ code but I’m not able to run my experiment (I’m quite new in Python+Psychopy)
The point is that I want to explore two different features of a font. Users will see a letter with an specific formatting (according to the two features) and are asked to identify it. Then, the output is correct/incorrect
Say that I want to explore one feature named ‘xopaque’ (ranging form 5 to 500) and another named ‘yopaque’ (ranging form 4 to 85). To the best of my knowledge, the QUEST+ implementation can explore two features in at the same time.
Am I right or it is impossible to explore these two features at the same time?
Thank you so much for your assistance


Dear @jon and @richard
First of all thanks a lot for all the work you are putting here. I am working with mvustarroz in this experiment but let me clarify a little bit what we need. We are exploring typographic configurations using a new format of fonts called variable fonts. This variable fonts allow the user to configure your own font a-la-carte in terms of different variables: width, weight, etc. In our case we are considering QUest+ to help us explore three diferent axis of variation that are interrelated, therefore a three dimensional space. We ve read that Quest+ is the right bayesian algorithm for this kind of complex exploration. It seems that mvustarroz is having issues in implementing the exploratory function in the second and third variable. We would be extremely thankful if you could help us in such task, thanks a lot

Dear Octavio,

I’ll be quite busy this weekend, but will try to get back to you soon.

Best wishes

Thanks a lot @richard :smiley: !!

@Octavio_Pardo Sorry for taking so long to respond, but I’ve been struggling with a fever for almost a week now, will try to get back to you until the end of this week.