Reference - visual encodings
A lot of research has gone into how we read visual encodings. This is a good summary from Munzner (2014), which you can read in full through UMBC’s library. There are also very thorough slides online from a course she taught on the same topics (this is on page 59).
Munzner, T. (2014). Visualization Analysis and Design. A K Peters/CRC Press. https://doi.org/10.1201/b17511
