The text describes an experiment in which a group of people are asked to rate how funny they find certain jokes. One group of people are asked to rate the jokes after being told that they were written by an AI, and another group of people are asked to rate the same jokes after being told that they were written by a human. The results of the experiment show that the jokes are rated as funnier by the group that believes the jokes were written by a human.
Which choice best describes the function of the underlined sentence in the text?