Professor Stephen Ceci taught his class the same way he had for the past 20 years, replicating nearly everything imaginable: same book, same lectures, same exams… even the same student demographics.
"He took great pains to make sure everything else about the class was the same as it had been the previous fall; he used the same book, the same lectures, the same grading policies, the same exams, the same office hours, the same syllabus, and the same slides, videos, and transparencies, and the student demographics were the same. He listened to the audio recordings he had made of his fall lectures and tried to memorize each before delivering it in the spring. He used the same detailed outlines and transparencies to ensure he talked about the exact same content.
At the end of the spring semester, two naive coders listened to several randomly selected lectures from both the semesters. They found 100 percent agreement in the ideas communicated in the fall and the spring."
There was zero difference in the content. The only change was this semester he presented more enthusiastically, gesturing with his hands and modulating his voice.