Hello!
I have a stupid question:
If I set the text stimuli size on PsychoPy (to be used on Pavlovia) height= 0.08, how can I report that in a paper (usually the pixel size or font size is reported)?
Many thanks!
The relationship between units is here:
https://www.psychopy.org/general/units.html
“Font size” is not meaningful here: it is a typographical concept, not a scientific one (i.e. if you mean something like “12 points”, that is a measure of the spacing between rows of text, not directly the size of the characters themselves).
Pixels (in terms of units) are easy to calculate, just 0.08/2 * your screen height in pixels. But again, that doesn’t tell you much about the size of the actual letters, which depends on the font chosen and the specific glyphs displayed. If you want an accurate measurement of glyph size in actual pixels, then the best approach is to take a screenshot and measure some given letters.
But the average scientific reader probably cares more about size reported in degrees of arc rather than relatively arbitrary units like pixels. For that you’ll need to use the tangent function, taking into account the physical size and distance of the screen:
Thank you ever so much.
I would not have this reporting problem if the experiment were not on pavlovia online, where the screen size and theoretically also the distance to the screen vary. I am aware of it and do not strive to control at least the former. My only problem is reporting the units I used (rather for reproducibility purposes). Can I just report Coursier, height = 0.08?
Many thanks!
Ah, OK, that makes a lot of difference. If it is important to you, then you could get the participants to go through a screen-scaling process, using an object of known size, like a credit card:
But if the detail is important, then yes, just say that the font was scaled so that the maximum height of any letter did not exceed 4% of the height of the screen. NB, most readers won’t know what “height = 0.08” means as the setting is PsychoPy-specific, so you need to spell out its meaning (and to be interpretable, halve it to 0.04, as explained in that units page).