Originally Posted by ColinsMum
Originally Posted by ultramarina
I also have mild face blindness, which must be memory-based as well.
Actually not really, as far as current understanding goes, I think. (I have moderate prospagnosia, or face blindness.) See e.g. http://www.ninds.nih.gov/disorders/prosopagnosia/Prosopagnosia.htm:
Originally Posted by NIH
Prosopagnosia is thought to be the result of abnormalities, damage, or impairment in the right fusiform gyrus, a fold in the brain that appears to coordinate the neural systems that control facial perception and memory.
(my emphasis)

ETA: Ha, someone has just done the experiment that I have long wished for someone to do:
http://brain.oxfordjournals.org/content/135/2/542.short
Full text free, and lots else, from this search.

About a decade later... a new report on a study regarding prosopagnosia (face blindness) - https://www.sciencedaily.com/releases/2023/02/230227132443.htm