Have you ever actually been persuaded/persuaded someone else in an argument?

[TJ in Oregon]

Yes but almost never to both. How easy it is to change someone's opinion depends a lot on the issue and often how well you know them. Let's face it, you're very unlikely to change someone's views on gay marriage when you're arguing with a complete stranger over the internet. Sweeping cultural views like that change slowly, often over the course of years, influenced subtly by many conversations and relationships. Smaller, less ideologically divisive issues can often be influenced by a conversation. I am almost sure I've changed the mind of a few friends on small issues over the years, such as how to vote in a levy or a referendum on whether or not a municipality should build a certain project, etc. Often changing someone's mind requires presenting the situation in a new way they haven't thought of before, a twist that reconciles divergent points. This tends not to be possible on divisive issues like abortion or gay marriage that have been argued to death and practically everyone has heard about. There may be some people in the middle of the issues who can be influenced by either side, but the people on each side are very unlikely to change their mind because of a certain argument.

I have noticed that most of the time when my mind has been changed by an argument, it was changed by someone I started off agreeing with. For example I used to be a huge advocate of legalizing gambling in Ohio, but switched positions after reading an editorial for the state referendum to build casinos. I used to support the death penalty, but was turned against it by someone arguing for it.