That's the scary thing. Facebook is good enough at influencing someone, but they do it for half the population of the world simultaneously.
- I can suggest you're biased
- I can try to change the subject
- I can decide you're a bad person for holding the "wrong" views
- I can directly argue against your point
- I can attack the structure of your argument
- I can make an emotional appeal regarding why I must hold my point of view
- etc ....
In these and other ways, I can push back and modify how much I'm influenced by a one-to-one argument. I won't always be successful, for sure. But sometimes as well the persuasion go will go the other way, and I will influence you.
This is not true on social media because another power is dictating which one-to-one conversations may happen in the first place, and then loading the deck with idea before those one-to-one conversations even happen. Further, social media changes the scale of communications. If we worked together, and saw each other regularly, we could mediate each other's influence, place boundaries, etc. With social media, there is always a crowd of strangers: too many people converse with, know, and set boundaries with.
There are obviously other distinctions between one-to-one conversation and social media, but I particularly wanted to talk about the key differences here: lack of real back and forth, and scale.
As a person, you can get better at convincing people of course, and masses of people even - humanity has gone through that with ups and downs. Now we have a system that's working totally differently. From example, I remind reading that many conspiracists build distance with their friends and family as they close themselves to in-person discussion or any argumentation not fitting their views.
Also, what about books? Ideas? Film.
IMHO people are too complicated, and situations too situation specific to be able to generalize about how someone is influenced.
Sometimes people ignore the advice of those close to them, sometimes they don't, and, it probably depends on the subject being discussed, the particular relationship between the people, the state of mind of the person in question, and so on.
I think for Facebook to be more effective than humans at influencing behavior, they have to implement theory of mind, which might require AGI.