Units of mouse coordinates

Online experiments
1

URL of experiment: https://run.pavlovia.org/Crible/testmtpolygon/html

Description of the problem: Hello everyone,
I’m designing an online mouse-tracking experiment in which participants have to click on (invisible) polygons with text when they hear a word. I’m trying to make sure that there’s everything I need in the .csv output so I have a few questions:

  1. I see in my experiments settings that the units are “height” by default, which I understand are relative to the window. Am I right that any x coordinate will then be relative to the center of each participant’s window? Or is it relative to where the mouse start at the beginning of the routine?

  2. Are height units what people usually use or do you have recommendations for other units? It’s my first time with mouse-tracking so I’m not really sure what’s best here. I only care about whether and when they will start clicking the left or right polygon.

  3. Should I also collect coordinates relative to the polygons? It’s been suggested to me by a colleague but I’m not sure how and why.

Finally, do you know if there is anyway that coordinates as well as time stamps for every frame would show up in the output in long format rather than as a long list of values per trial?

Any other advice on these matters is welcome! Thanks a lot,
Ludivine

2

Mouse coordinates are relative to the centre of the screen.

Height coordinates work best since they scale but maintain aspect the ratio. I sometimes use norm for instructions.

However, I would recommend that you use the contains method for polygons, not coordinates.

Best wishes,

Wakefield