Ask somebody for a two-digit number where both digits are odd and different from each other, and performers have expected the same answer for decades.
Think of a two-digit number where both digits are odd, and different from each other.
So 11 does not count — the digits are the same. Twenty numbers qualify.
37. It is one of the best known psychological forces in mentalism, and the expectation is repeated wherever the trick is taught.
The published evidence is indirect rather than absent. Kubovy and Psotka found that 28.4% of 558 people asked for the first digit that came to mind said seven, and that people shy away from the ends of whatever range they are given. The pull toward sevens, and away from the edges, is the same effect one range up — and 37 is the number that inherits both. A direct measurement of this exact question is what the count above is for.
Out of 0 answers so far. Free to quote, with the sample size beside it so a reader can judge the weight.
Once this passes 1000 answers, the measurement replaces the claim above as the headline of this page, and the claim becomes the thing being checked rather than the thing being reported. Saying that in advance is the point: a threshold decided afterwards is not a threshold.
Read the question again and notice how much it removes. Both digits odd rules out eighty of the ninety two-digit numbers. Different from each other rules out the five repeats. What is left is exactly twenty: 13, 15, 17, 19, 31, 35, 37, 39, 51, 53, 57, 59, 71, 73, 75, 79, 91, 93, 95 and 97.
Twenty is small enough that a guess has a real chance on its own. But the answers are not spread evenly across the twenty, and that is the part performers rely on.
Asked to pick something arbitrary, people work by elimination without noticing they are doing it.
They avoid the ends — the YouGov survey found exactly that in the smaller range, with one, two, nine and ten all unpopular. They avoid anything carrying an association, which takes out 13 and most of the nineties. And they avoid whatever occurred to them first, on the grounds that it seemed too easy.
That leaves the middle of the range, and 37 sits there wearing the most convincing disguise: two odd digits, neither of them 1 or 9, prime, no obvious meaning attached. It feels like nothing in particular. The trouble is that it feels like nothing in particular to a very large number of people at the same time, which is precisely what stops it being arbitrary.
Write 37 on a card, put it face down, and ask the question. If the answer comes back 37 the effect is finished and it looked like mind reading. If it does not, the card is never turned over, and the performance moves on.
That is the whole trade, and its value depends entirely on the true rate. At 30% it is an opener you can build an act around. At 8% it is a coin flip in a dinner jacket. The folklore has never said which, because it was never counted.
Because the instruction eliminates all but twenty numbers, and of those twenty, 37 is the one that feels least like a choice. People avoid the ends of the range, avoid numbers carrying associations, and avoid whatever seemed too obvious.
37 survives all three filters for a great many people at once, and that shared sense of arbitrariness is what stops it being arbitrary.
Twenty. They are 13, 15, 17, 19, 31, 35, 37, 39, 51, 53, 57, 59, 71, 73, 75, 79, 91, 93, 95 and 97.
A blind guess is right one time in twenty. Any rate above that is the psychology rather than the arithmetic.
No, and a performer using it plans for the misses. The prediction stays face down unless it is right, so a wrong guess costs nothing but the moment.
How often it works is a number rather than a belief, which is why this page collects answers instead of repeating the claim.
This is one of eleven questions in the full study, which asks for a card, a number, a vegetable, a fruit, an animal and more, and shows the running counts for all of them. The rest of the site is self-working card tricks you can play in the browser.