One question that I'm curious about with respect to EA strategy is the extent to which people are or are not willing to change not just specific organizations they might donate too, but overall cause areas that they consider important focuses. I'm especially interested in "average donors" and people who are not necessarily explicitly EA -- I think this question is quite meaningful with respect to what kinds of outreach most generate value in the world.
Is there any research into this topic people could point me to, either from within the EA community or elsewhere?
I think there's definitely something to this.
As is suggested by this report, even donors who are very proactive, are often barely reflecting about where they should give at all. They are also, often, thinking about the charity sector in terms of very coarse-grained categories (e.g. my country/international charities, people/animal charities). On the other hand, they often are making sense of their donations in terms of causes and an implicit hierarchy of causes (including particular, personal commitments, such as to heart disease because a family member died from that, and so on). They also view charitable donation as highly personal and subjective (e.g. a matter of personal choice) [there is some evidence for this in here and unpublished work by me and my academic colleagues].
I think the overall picture this suggests is that people are sometimes thinking in terms of causes, but rarely explicitly deliberating about the optimal cause or set of causes.
To address the original question: I think this suggests that trying to get people to "change causes" by giving them reasons as to why certain causes are best may be ineffective in most cases, as people rarely deliberate about what cause is best and may not even be aiming to select the best cause. On the other hand, as many donors give fairly promiscuously or indiscriminately to charities across different cause areas, it's plausible you could get them to support different causes just by making them salient and appealing.