Do we have strong evidence that "average donors" even have "cause areas," as an accurate/descriptively useful mapping of how they understand the world? My young and pre-EA self feels so distant from me that it's barely worth mentioning, but I vaguely recall that teenage me donated to things as disparate as earthquake relief in Sichuan, local beggars, LGBT stuff and probably something something climate change.
I don't think I ever consciously considered until several years later how dumb it was to a) donate to multiple things at the tiny amounts I was donating at the time and b) to have multiple cause areas of very varying cost-effectiveness and theories of change.
Rethink Priorities' analysis of the 2019 EA survey concluded that 42% of EAs changed their cause area after joining the movement, 57% of change was away from global poverty, and 54% towards long term future / catastrophic and existential risk reduction.
Rethink Priorities, and Faunalytics also have much content on how to do effective animal advocacy, which would likely be useful for your purposes.
This is probably not the extent of research that Rethink Priorities has on this issue, but it's what I could remember reading about.