In a study, participants watch a video (with no sound) of two people in a vigorous discussion. After the video, researchers tell
participants in one group that the video was of two friends in an unpleasant argument. They tell participants in a second group that the video was of two friends enjoying a lively discussion. Participants in the first group, who were told the discussion was an argument, were more likely to report that the people in the video were yelling, frowning, and getting angry. Participants in the second group, who were told the video was of a lively discussion, were more likely to report that the people in the video were smiling and laughing. This is an example of what common principle
