Daymon is a behavior therapist and he was conducting a study on how child X - diagnosed with autism - verbally responded to the introduction of a strange animal in the room. His research involves an ABAB design in which he observed Child X's behavior through a two way mirror in stage 1 for 5 minutes during which he counted the number of vocalizations Child X made. In the second stage, Daymon put a cat in the room and continued to observed child X's vocalizations for another 5 minute period. In the third stage, Daymon removed the cat from the room and observed child X's verbal behavior for a 5 minute period and in the last stage Daymon reintroduced the cat once again and observed child X's vocalizations for a final 5 minute period. This type of research exemplifies: