I noticed a pattern of "stages" people go through as they learn more about policy/economics.
People start out with ideology. They are for or against something because it pulls their heart strings the right way. I'll illustrate all the examples from foreign aid. For most people, the knee-jerk reaction to foreign aid is that it is obviously a good idea. Don't you feel bad for those starving Ethiopians?
Then people learn a talking point that supports their ideology. For foreign aid this might be an example of miracle growth following aid, like the Marshall Plan, or how a specific type of aid is effective. For instance, they might learn to explain how micro-finance is like teaching people how to fish and letting them pull themselves up by the bootstraps.
I think most people stop on most issues at this stage. If they go beyond it, they usually change their opinion. An aid supporter will come across arguments that aid doesn't work and jump on that bandwagon. They replace the positive talking point with a negative talking point: aid harms recipient countries because it removes the incentives for politicians to be accountable, or something like that or RCTs on microfinance don't show a mass exodus from poverty, or even big consumption gains.
Eventually people progress to the last stage. They synthesize the evidence on both sides and come to terms with a more moderate position--often one not far from their initial beliefs. They come full circle and internalize the evidence researchers have documented about the issues in full. Aid skeptics give way to tempered optimists: aid may or may not cause growth, it can have a negative impact on exports, it does save many lives when used on targeted public health interventions. Microfinance transitions from being about poverty to being about control of your finances and peace of mind.
The most common cycle I see on this front is the "economic issues" cycle where most young people start out idealistic and to the far left. They want a big welfare state, or communism, so that people don't have to live in poverty. Then they learn talking points about how perfect markets make everyone better off (not phrased like that of course) and then they come back to tempered belief in markets. They work sometimes, but asymmetric information, externalities, and culture/institutions complicate everything. Markets aren't always the answer.
What I'm describing sounds like a standard Hegelian dialectic, but what interests me is the psychology of how and why people seek out the information they do. People start out only interested in backing up their ideology with talking points. Eventually they shift to wanting to be "knowledgable" about a subject. Finally, they mostly are interested in the facts. A lot of people probably never get past stage two. It bothers me when people are stuck in stage three (libertarians). The best people to talk to are, needless to say, in the final stage.
I should probably add a stage zero: willful ignorance. Sometimes people don't care and don't see any reason to get informed. It sounds bad but that is most of us on most issues. I like it when people admit willful ignorance before stating their ideology.