Quest staircase works locally on PsychoPy but not on Pavlovia - values in csv spreadsheets not used

Online experiments
1

Update:

Since posting this query, I have tweaked the values in the csv spreadsheet which then seem to work. I reduced the “startValSd”, and increased the “range” which seem to stop the error from happening. Instead of using StartVal as the starting value of “level” (how it works in PsychoPy), in Pavlovia, level seems to be determined by the StartVal and the StartValSd.

However, the Quest staircase calibration seem to never end. I have set up 32 reps on the Quest staircase loop, but after nearly 100 trials, Quest calibration is still going. I am not sure what criteria needs to be met (reversals?) for Quest calibration to finish.

I’ll continue working on this. Any comments or advice welcome (on how to end Quest calibration).

Thank you.

The Pavlovia link for this task is VisDisc75 [PsychoPy]

Hi there,

Sorry to repost this issue - I had accidentally deleted my original post.

I have created a visual discrimination task in PsychoPy, asking participants to choose the “lighter” grey square. I am using the QUEST staircase function to calibrate the difficulty so participants achieve 75% accuracy.

This task works as it should when run locally on PsychoPy. When I pushed it onto Pavlovia, it does not seem to read the values from the data spreadsheets. The “level” parameter is not reflecting “StartVal”, or “range”. It defaults to 0.319 at the start, then slowly decreases in value until it is near or around -0.75, then an error occurs as the value that specify the grey hue is beyond the range of [-1,1].
I have installed the latest PsychoPy version (2024.2.4), recreated the task and the problem is still the same (the same issue also occurs on the 2022 version of PsychoPy).

Does Quest work online in Pavlovia? Is there something I am not doing to link the csv data files to the task PsychoPy file? (It works locally on PsychoPy but not in Pavlovia)

Many thanks.
Michelle

2

Hi - You’ve probably seen this link to your problem re quest not ending: QUEST loop not terminating online - #6 by ContofalskyR

I was wondering how much you had to reduce/change your values. Everything works fine for me for my QUEST in Python/Psychopy but JS/Pavlovia it’s reducing level to minuses? How did you predict the values or did you just trial and error?

Thank you.

3

Hi there,

The reason why I was getting negative level values was because my levels were too close to 0. A small level value seem to push the staircase algorithm to output a negative level value, ending up in an error. To avoid negative level values, I coded in PsychoPy to multiply the level value by 100, so my level values are not too close to 0. This worked for me - I hope this helps.

1 Like