Bonucci says Rice made the mistake of a young player and was “presumptuous” about the result when he said ahead of the final that England were “ready for it 10 times harder than” Italy.
Italy won the final on penalties after the game ended in a 1-1 draw, but Bonucci said the comments fired Roberto Mancini’s side.
While Southgate is aware that the comments may have been inflamed at the time, he believes Rice will learn from the experience.
“I guess it’s a reminder that you should always keep in mind what you are saying when speaking in public,” Southgate said.
“It can be used as motivation for an opponent. We have done this in the past and it has been beneficial to us.
“I’m sure sometimes these things can be taken out of context a little bit and that can make it even more inflammatory. I’m sure if that was the case, Declan would have learned of the situation.
“I don’t really know what he said, exactly how he got started and what was five minutes before and five minutes after that gave him context.
“As a manager you wouldn’t mind because you would just stick something on the dressing room door and use it for your own purposes.
“We have to be savvy enough to understand this and clearly the Italians may have used it. The game was a draw, we have to remember that it was a draw. Even though they were worthy tournament winners, I don’t really think that’s what made the difference. The result of the final was much more than that. “