I’ve noticed that if I run the exact same program on different versions of the Psychopy the fixation cross displays on one version but not on the other. I couldn’t understand what was happening until I realized that if I set the height parameter to anything above 2 (on Psychopy version 1.85.2), the fixation cross stops displaying. 1 or 2 it displays but 3 or 4 it doesn’t. The same thing happens when I change the height value to any TextStim object. Does anyone know why this is? Is it because the maximum value height can take varies across different versions of PsychoPy?
The height parameter will depend on the units you are using https://www.psychopy.org/general/units.html (note ‘height’ and ‘units’ are different parameters, but you can also set ‘units’ to be in terms of ‘height’). The default units in psychopy builder has now been ‘height’ for a while now, for the reason that it will scale stimuli to window size, which makes for easy transition online where participants may have a range of window sizes.
Some units will differ depending on the details in your monitor centre. I think that the link to the documentation above should help aid understanding there
Thanks for the information. I haven’t set this “units” parameter at all so i would presume from that that I am therefore using the default. So why is it in that case that changing the value of the height parameter above 2 suddenly makes the text not appear?
Whilst I cannot directly speak to the version of psychopy that you are using (v 1.85.2 is quite an old one now and versions pre 1.9 are not supported in the ‘use version’ option of psychopy) this will depend both on the units you are using (if you haven’t changed the units parameter check in preferences>units or if you are using builder experiment settings>units) and the parameters that you have in your monitor centre, If either of those differ between the installed versions of psychopy that you have then the stimuli will appear different.
Note also that for some units (e.g. norm and height) values of 3/4 would exceed the window dimension, so stimuli would not appear onscreen.
Hope this context helps,