Polygons appearing elongated when running task on MR monitor but not on scan room monitor

OS: Win10
PsychoPy version: 2023.1.3
Standard Standalone? Yes
What are you trying to achieve?:

We are using Psychopy for an fMRI experiment in which we’re using a few different simple Polygon components (circle, square, cross, etc.) as stimuli. We have a display monitor in the scanning room (Nordic NeuroLab LCD monitor) that backprojects the display monitor in the control room. It is setup so that the full display of the control monitor (60 x 33.5 cm, 68.5 cm diagonal) appears on a portion of the scan room monitor width (i.e., the full dimensions of the scan room monitor are 90 x 48.5 cm, 101.6 cm diagonal, with the duplicated display 66 x 48.5 cm). The control room and scan room monitors are each set to 1920 x 1080 resolution.

We are using ‘height’ units for the task. When presenting the task, it appears perfectly on the control computer, but on the scan room monitor, the shapes are all elongated in the vertical (y) direction. We are unsure what can be changed in the monitor settings to fix the appearance on the scan room monitor.

What did you try to make it work?:

We adjusted the resolution settings of the control monitor, and also the monitor settings in Psychopy (size and screen width) and screen properties (window size).

What specifically went wrong when you tried that?:

The task runs but the shapes remain elongated on the scan room monitor. The other option we considered was to change all of the shape dimensions in the builder so that it appears correct on the scan room monitor or use different units (cm), but ideally we can continue to use height units.


As the two monitors have different heights, the polygon will look distorted on one of the two monitors. See here for the different units PsychoPy offers


Best wishes Jens

Hello @JensBoelte ,
Thank you for your answer!
I have the same problem. If i want to continue using height as a unit, the solution would be to create a second monitor, with the dimensions of the scan room monitor, in order to appear distorted in the
control room but ok in the scan room?
Thank you for your time.
Kind regards,