Mac Issue Recognizing Keypresses Online?

Online experiments
1

I have an Online experiment in Pavlovia that was built in Psychopy Builder (v.2025.1.1). It works mostly perfect across devices (Lenovo ThinkPad, Mac Pro and Air) and browsers (Safari, Google Chrome, Edge). However, it sometimes does not work for people using Macbooks specifically. However, this is not the case for all people using a Mac and completing our experiment.

To do the experiment, subjects must use the space bar, and either repeatedly press the ‘S’ key or the ‘L’ key depending on whether they are right-handed or left-handed. Both of these keys are in the keyboard component as ‘s’ and ‘l’. Pressing the S or L key will cause a bar to fill up. When there is an issue, the space bar works (which moves instructions pages forward), but the S key does not (which means the bar does not fill up). The output shows that the first S key input is recorded, but subsequent S key presses were not recorded.

We have successfully run the experiment on a Macbook Pro on OS 13.7.6, Macbook Air on OS 14.6.1, another Mac with OS 14.6.1.

Due to the fact that the experiment works with most Macs, I am wondering if anyone knows of specific keyboard or privacy settings that might get in the way of Pavlovia recognizing key presses?

Thank you!

2

Dear Solivares,

This might be an issue with the keyboard backend (Properties → Input) and for whatever reason the specific Apple OS or keyboard hardware/software is unhappy. Try testing using Pyglet or Psychtoolbox and see if the error occurs (and that the experiment still functions properly).

Also if this is an issue that only participants report, but you may have not come come across, it may be a participant problem. It could be that the participant is just holding down the “S” key rather than repeatedly pressing it. Do you have access to the key release timing to check that at all?

Issac