For instance, in one experiment the researchers praised him, trying to elicit a happy reaction; Mal looked at the camera with his ears erect and tongue lolling. Then they reprimanded him, and Mal's ears flattened, he looked down and his eyes became mournful. They used a jack-in-the-box to surprise him; foul-tasting medicine to disgust him; nail trimmers to strike fear into his heart; and so on. One of the researchers even pretended to be a criminal, and Mal got angry. Then the team showed 50 volunteers photographs of these reactions, and asked them to categorize his emotions.