My Barnum Effect Test

Dear reader,

well, it's not mine. The experiment is old, of course. The magicians Penn & Teller did their version in their series "Bullshit" (season 7, episode 2: Astrology). Derren Brown shows this experiment as part of an episode of his series "Trick of The Mind" (season 3, episode 1). Which are only two that come to my mind right away, which I've seen myself. Others have done that experiment, too and towards the end of my studies at uni, I did as well.

I talked to the professor of a psychology class. The class was, at least in theory, about doing things and not just teaching and theory. The right course for my experiment, I thought. So I asked the professor if it was okay if I did a little experiment I had thought of doing for a while already. She agreed, so the week before easter holidays, I came in with yellow index cards I told others that over the course of the semester holidays, I had worked on creating a personality test program and would like to test its accuracy with them. I told them to write down: on the left top corner the day of birth, should they know it, also the time. But it wasn't necessary for me to have the time. On the right top corner they were to write a code of any combination of numbers and letters. Just so they knew theirs. In the middle they should write one short sentence that described them. (I should give Penn & Teller credit for that one. In their Bullsh!t episode on astrology, they let a psychology professor do exactly that. Since I couldn't come up with anything else as a basis for information.)

Then the easter holidays came and then the first day after the holidays came and the seminar was later that afternoon. So plenty of times for fellow students to approach me and ask about the test. Well, two came up to me right after the first seminar that day. One saying that she changed courses, but should I have the results, she'd like to know hers. I gave her her index card. The "result" I had stuck on the back of it with a paper-clip. I told her the truth right away that the twist to this wasn't so much the text, nor the test, but how they reacted. Another girl approached me saying she had an appointment at the doctor's. She'd try to change it, but couldn't. I desperately hoped the wouldn't tell the others about my text!

Anyway, I came into the room where the seminar would be held. One girl came to me and asked me about three times, "Are you going to tell us now?" She was really eager.

A short break time during the seminar was my time. I said, "Last time I asked you to fill out index cards for me for a personality test. I've got the results now. Please, pick your card and read it quietly for yourself. Don't share it with others. I want to ask you for quick judgment about how well it fits you." They went and read their card. I asked, "On a scale from 1 to 5, 1 meaning doesn't fit and 5 means it fits, how many think it sucked? 1?" No one. "How many say: a bit? 2?" Still no one. "How many say: so and so? Kind of half half? 3?" Two or three raised their hands. "How many say 4?" I didn't count, a good deal of people. "5?" The rest of them. One half joked, "Mine's like 4.5." That got a laugh. I said, "Of those, who say it's 5, would any of you care to read like the first two or three sentences for us? Just to show how a well done one would have looked like?" One started reading hers. The others started smiling and looking at each other. The reader asked me, if she should go on. I thanked her and said, it was enough and that the reason why the others smiled was, because they had the same text.

"You all have the same text", I said. "And here's another truth: that program I told you about doesn't exist." I could feel the relief that spread in the room. "I didn't even write the text. The text is from the wikipedia entry to 'Barnum effect', which is what happened here: if you have a bunch of information, you pick the things you think fit and make them fit to yourself. Barnum was a circus director, who had that motto of: a little bit for everyone." I went a bit on and then told them about, also that fortune tellers and the like use this technique.

I told them that my mom had told me about an aunt, who had went to a fortune-teller. She told that aunt that she was about to die in a car within the next 1 to 3 months. I said, "She lived longer than 3 months. But can you imagine - and we're right into the topic of this seminar here - the mental stress she would be in, every time she had to go into a car? This could be the one, she'd die in." I said, "So maybe you say: well, that's fortune-telling. I don't believe in that anyway. But you did believe me."

I was about to leave it at that, but one girl raised her hand and asked me something I don't remember anymore. It got us into a quite relaxed, but interested and interesting discussion (probably for 10 to 15 minutes, in any case longer than the teacher intended for that break) about fortune tellers, cold reading and the like. I felt good. It's one thing watching videos of Derren Brown or others doing it or reading about it. It's another to be able to feel that they believe you and knowing you cheated on them. I knew they wouldn't like strangle me or something. But I was quite nervous as to how they would react. I was very pleased how they reacted. Even surprised to find that they actually had questions and were really interested in knowing and discussing more!

Until next blog,

sarah