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Multiple values in mouse tracking variables

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#1

OS (e.g. Win10): OSX Big Sur
PsychoPy version (e.g. 1.84.x): v.2020.2.10
Standard Standalone? (y/n) If not then what?: y
What are you trying to achieve?:
I have a Fitts-type task and would like to track mouse position in x and y for every frame as well as trial time.

What did you try to make it work?:
I set up a mouse component with one clickable stimulus (target) and set save mouse state to “every frame”

What specifically went wrong when you tried that?:
Include pasted full error message if possible. “That didn’t work” is not enough information.
The CSV results file contain multiple values for mouse position (mouse.x and mouse.y, mouse button responses, and mouse.time). There doesn’t seem to be one record for every frame, as the interval between two values of mouse.time is not constant. What exactly do these multiple values refer to ?

Many thanks for your help !

#2

Going through each:

  • mouse.x is the x position of the mouse, i.e. horizontal position on the screen
  • mouse.y is the y position of the mouse, i.e. vertical position on the screen
  • mouse.leftButton is whether or not the left mouse button was clicked
  • mouse.middleButton is whether or not the middle mouse button (scroll wheel) was clicked
  • mouse.rightButton is whether or not the right mouse button was clicked
  • mouse.time is the time this sample was taken

When it’s set to Each frame, it will store the responses as a list (e.g. [value, value, value]), that list is the value of that parameter at each frame, in order.

#3

Thanks very much TParsons ! I guess I was thrown off a little. Surely the interval between two successive frames (mouse.time) should be constant ?

#4

There’s always a little variation between them, but it should be negligible - how much does yours vary by? If it’s a lot (more than 1/60th of a second for example) then that’s potentially a problem