Google Trends - Psychology of Vision, Nov. 7, 2015 (Updated 2020)

One thing to keep in mind is the phrase "psychology of vision" is also used in ophthalmology and art.

https://www.google.com/trends/explore#q=%22psychology%20of%20vision%22&cmpt=q&tz=Etc%2FGMT%2B8

Updated chart: 2004-Jan. 2020 (below)