In a communicative situation, talking the most, interrupting the other person, and changin the topic most often are all common indicators of conversation control.
Despite being also rude behaviours, thee elements indicate that the speaker is in control of the conversation or the debate, perhaps taking advantage of the other speaker's more polite behaviour or his / her inexperience in a debate.
If the speaker can change the topic and speaks more that his / her counterpart, that speaker is clearly controlling the conversation.