Some changes require a substantive learning process, such as hours of intentional, focused practice. There are other options too, like reading several books over the course of a few months and thinking about it many times during those months. Or you can immerse yourself in a subculture, for months, that's good at the issue. A substantive learning process involves visible actions. If it happened, it should be pretty easy to point to some evidence and activities.
Some changes don’t require a substantive learning process.
If someone says they changed in a way that requires a substantive learning process, but they can’t or won't point out the learning activities they did, then you shouldn't believe that they changed. They might not know how to say what they did, but more often they just didn’t change.
Suppose someone says they stopped being angry but can't specify anything they did to fix their anger problem. Is it more plausible that they just don't realize that anger management classes, meditation, therapy or reading a book should be mentioned as activities they did in order to change? Or is it more plausible that they didn't do those things? (Or they may have tried some of those things unsuccessfully.) And if they didn't do those things or anything else major, then it's very doubtful that they really changed. Maybe if you knew them 30 years ago and they say they stopped being so angry since then but can't point to specific activities, that would be plausible, but if they were an angry person 6 months ago, then they wouldn't have changed without taking identifiable actions to change.
Or imagine someone claims they’re really good at chess, but they can’t point out learning activities they did like spending hours playing or studying chess. What can you conclude? They aren’t really good at chess. Being good at games or sports requires substantive learning processes. (However, skill at one sport or game can carry over to another. Good chess players can learn go and other board games more easily. Good baseball players can learn cricket more easily, and possibly basketball too. Good video game players are often good at new games.)
If someone claims to really value Critical Fallibilism (CF), that requires a substantive learning process. It’s not the default. It’s not a widespread part of our culture that people pick up during childhood. It’s not taught in school. At some point in their life, they had to significantly change and learn in order to understand CF or highly value it.
In discussions, people sometimes say they changed their mind. They say that they were persuaded by an argument. Often, that means they changed their conscious mind, which can happen fast with no substantive learning process. But they won’t act on those ideas, or remember them at other times they’re relevant, unless they go through a substantive learning process. A substantive learning process is necessary for your subconscious mind to learn and change.
When someone says they changed their mind, it can mean they will be researching the topic more over the next few months. It can mean they’ve consciously changed their mind and now they’ll begin a substantive learning process in order to change their subconscious too. But that isn't usually what people do. That’s why persuasion often doesn’t last.
Sometimes it’s hard to tell if substantive learning is required. Suppose I learn to play a video game with a mouse but then I switch to a joystick. Do I need to relearn how to play? It actually depends on the game. If it’s a fast-paced first person shooter, learning to aim with different controls can be a big issue. If it’s a slow, turn-based strategy game, then my learning focused on the strategy not the controls, so switching controls would be easier.
If you’re racist and someone convinces you to stop, you’ll need to rethink all kinds of things from a non-racist perspective. E.g. you’ll have to revisit your racist interpretations of history. Changing will be a lot of work. You can’t just say “I get it now; I’d never heard that argument before” and stop being racist in one day. Racism is in your subconscious; it's not just a few explicit statements in your conscious mind. You may have to reread some history books while keeping your new ideas in mind in order to change how you view the book topics. You may need to read some new history books that offer perspectives you hadn't taken seriously before. It will take you a long time to work out all the implications. Your ideas are connected in a complex web, so changing one idea can lead to changing another which is connected to several more.
To stop being racist, you may also have to revisit your interpretations of IQ, tattoos, hair styles, beauty standards, fried chicken, other English dialects, poor people, drug addicts, criminals, and many other issues. You should be careful with any negative judgments you have that apply to a race you had a bias against. Sometimes people make excuses like "Yeah, black people are fine, but not black criminals. Obviously criminals of all races are bad." Then they don't reconsider their views and don't realize that racial profiling, police bias, biased lawmakers and other issues make black people more likely to be falsely imprisoned or to accept unfair plea deals.
If someone persuades you that all quotes should be exactly, literally accurate, you might be able to change in one day. Going forward, you might be able to always use copy/paste instead of typing the quote. Or not. I've witnessed many people fail to change their quoting practices quickly. You may need to practice quoting correctly before it sticks, but it seems possible that you could change how you quote without practice (and without researching the topic, pondering the topic, or other forms of putting in significant effort). Sloppy quoting might not be integrated into a bunch of your other ideas in the way racism typically is (for example, you might not have used quotes very much in your life so far).
It's much easier to know when quoting has come up than when racial issues are relevant. You could stop and take your time every time you use a quote until you become good at it. Instead of practice quoting now, you could do it slowly and correctly every time you want to quote going forward. In other words, you could do your next 50 quotes using conscious attention – you just need to consciously know how to quote correctly, recognize when to use conscious effort, be willing to do it, not be rushed, etc. That wouldn't work with racism. It's too hard to recognize when racial issues have come up and then take conscious control over your thoughts and actions. Racial issues are hard to work out in real time, whereas accurate quoting can be done with reasonably little time and effort even if it isn't habitual and your subconscious can't do it.
Substantive learning processes are necessary when substantive changes to your subconscious are necessary. Your subconscious can’t change in a big way without putting in work.
Sometimes (not usually, but sometimes) people break habits abruptly. How? The most typical way is they decide to break the habit, then they do a substantive learning process. They put in conscious effort for the next month (so they can do it the right way before their subconscious has changed), and during that time their subconscious changes. This is the same concept as someone in a discussion saying they’re persuaded, and then following up and doing the work to change their subconscious over the next few weeks (rather than, as is more common, not doing additional work, and becoming unpersuaded over the next few weeks as their conscious opinion switches back to match their unchanged subconscious).
In programming terms, sometimes you just have to change the value in one global variable and you can get a big difference in the output of a program. That is the kind of quick, small change that doesn’t require a substantive learning process. It can be hard to tell what changes can be achieved in that way and what changes actually require substantial revisions to the (subconscious) code. But we can often make a good guess. You may get into a disagreement with someone about whether a change is substantive or not, but often people agree about whether an issue is substantive. Figuring out what changes are substantive is also a skill that you can improve at over time as you get more practice and experience with it.
What changes require a substantive learning process can vary by person (just like it can vary by codebase – two different email apps could be written in different ways, so for one app a particular new feature is easy to add, and for the other app the same feature is a ton of work to add). But, for many issues, there’s a ton of overlap between people. For most people, for most issues, they’ll either both need a substantive learning process to make a change or they both won’t.
In my experience, in discussions, people often claim that they changed in ways that would require a substantive learning process. But they don't know that and don't even claim to have done one. They just assert that they changed and think people should believe them. People also fool themselves this way. Instead of doing the work to improve their flaws, they just decide on what changes they'd like, don't do the work to change, and then consciously believe that they changed. Thinking about whether a substantive learning processes is needed, and if so whether it took place, can help you deal with both other people and yourself more effectively.