Basically a cataloger is a collector. If the cataloger is employed as a cataloger, the collecting is done for him. If the cataloger is a hobbyist, he has a subject of interest and he collects all things related to it. For example, if the subject is music, he will not only collect (and catalog) various genres of music, but will likely collect books about music, concert programs, and even articles from magazines about music.
There are collector-catalogers for practically any subject one can conjure up. Museums (probably the biggest of the collector-catalogers, right after libraries) are often funded by universities or cities. If one doesn’t personally like to collect, most people still like to go look at the collections of others (in museums, usually.)
Collecting and cataloging seems to be an analytical exercise. People seem to have an urge to collect and classify as many examples within their field of interest as they can, sometimes doing it over their entire lifetime. Those who collect but don’t catalog may have large collections, but they are just stored in boxes in the attic - or all over their house. An unordered collection is not very useful to the collector or anyone else.
I have often thought about the psychology of collecting, but haven’t come up with an explantion for it that is very satisfying. I haven’t found anyone else who has either. Perhaps a need to preserve and document. If so, that still doesn’t tell us why there is a need felt inside a collector to do that.
If anyone has a theory, I would love you to talk about it.