# Statisfaction

## Psycho dice

Posted in General by Pierre Jacob on 30 November 2011

In a failed attempt to escape from statistics by reading a novel (Midnight in the Garden of Good and Evil, by John Berendt), I discovered a game called psycho dice. One of the main character, Jim Williams, explains it as follows.

“I believe in mind control,” he said. “I think you can influence events by mental concentration. I’ve invented a game called Psycho Dice. It’s very simple. You take four dice and call out four numbers between one and six–for example, a four, a three, and two sixes. Then you throw the dice, and if any of your numbers come up, you leave those dice stand-ing on the board. You continue to roll the remaining dice until all the dice are sitting on the board, showing your set of numbers. You’re eliminated if you roll three times in succession without getting any of the numbers you need. The object is to get all four numbers in the fewest rolls.”

Williams was sure he could improve the odds by sheer concentration. “Dice have six sides,” he said, “so you have a one-in-six chance of getting your number when you throw them. If you do any better than that, you beat the law of averages. Concentration definitely helps. That’s been proved. Back in the nineteen-thirties, Duke University did a study with a machine that could throw dice. First they had it throw dice when nobody was in the building, and the numbers came up strictly according to the law of averages. Then they put a man in the next room and had him concentrate on various numbers to see if that would beat the odds. It did. Then they put him in the same room, still concentrating, and the machine beat the odds again, by an even wider margin. When the man rolled the dice himself, using a cup, he did better still. When he finally rolled the dice with his bare hand, he did best of all.”

From the few rounds we played, I could not say whether Psycho Dice really worked. Williams had no doubt that it did. He saw proof of it at every turn. When I needed a five and rolled a two, he proclaimed, “Aha! You know what’s on the other side of a two, don’t you? Five!”

So I was a bit surprised by the existence of such a study from Duke University, and it turns out to be true: the apparently famous Joseph Banks Rhine indeed studied psychokinesis with an experiment similar to what is described in Berendt’s novel. Excerpt from Wikipedia:

In the later 1930s, Rhine investigated “psychokinesis” – again reducing the subject to simple terms so that it could be tested, with controls, in a laboratory setting. Rhine relied on testing whether a subject could influence the outcome of tossed dice – initially with hand-thrown dice, later with dice thrown from a cup, and finally with machine-thrown dice.[1]

So I guess it was easier to publish in the nineteen-thirties.

### 9 Responses

1. Michael Nestrud said, on 30 November 2011 at 15:58

At the beginning of the original Ghostbusters, Egon uses the famous Rhine card deck to impress (I believe) Sigourney Weaver. I often use the deck in demonstrations – it works best if you have 25 students in the class, because by sheer probability (at p<.05) one of them is psychic.

2. disgruntledphd said, on 30 November 2011 at 16:30

Rhine’s experiments were extremely controversial in their day, and indeed to this day.

That being said, if you look at all of the studies published by his lab (discounting a number of studies in which fraud was shown to be involved), he certainly appears to have demonstrated some kind of effect unlikely to be due to chance. What that effect was is unknown, but its hardly appropriate on a statistics blog to snark without looking at the evidence, when there are so many better targets.

• Pierre Jacob said, on 30 November 2011 at 18:29

Michael: interesting, thanks for the teaching tip! It sounds fun.

Disgruntledphd, thanks for your interest. I am sure Rhine “certainly appears to have demonstrated some kind of effect unlikely to be due to [anything]”, considering the vagueness of this claim. I haven’t read all the studies published by Rhine’s lab, of course I haven’t read any of them. In case it wasn’t clear enough, I was reading a book, I was intrigued by the mention to a far-fetched study from Duke University, found that it existed indeed and that this Pr. Rhine seems to be an interesting and famous character, so I blogged about it, thought it was fun. Is it what your PhD is on, Rhine’s results? You’re mentioning controversy to this day, can you point to recent serious or peer-reviewed articles debating them?

3. Pierre Jacob said, on 30 November 2011 at 18:30

Also if you can send us a list of things we should blog about instead of our inappropriate posts, we’d be very interested.

• disgruntledphd said, on 30 November 2011 at 18:44

I would probably start with almost anything in psychology (just pick an article at random, they’ll all have horrible mistakes and misinterpretations).

Note that I didn’t think the post was inappropriate, it just annoys me when people pick on easy uncontroversial targets such as psi, rather than the targets that actually materially matter to our species (medicine, climate models etc).

• Pierre Jacob said, on 30 November 2011 at 18:59

OK well I guess it’d be really interesting to pick serious and controversial articles and to comment them. It is just not exactly what this blog is about, which essentially is sharing useless information, crazy data sets and so on.

And still, as uncontroversial as my post is, you complain!

4. Julyan Arbel said, on 1 December 2011 at 20:59

Here’s a (skeptical) review of Rhine’s book, The Reach of the Mind, 1947: http://ajp.psychiatryonline.org/data/Journals/AJP/2400/716.pdf

5. Psycho dice and Monte Carlo | Statisfaction said, on 16 December 2011 at 17:48

[…] Pierre’s post on psycho dice, I want here to see by which average margin repeated plays might be called […]

6. […] Display a unique item associated with a character {I set out Psycho Dice} […]