This hack shows where
This hack shows where some specific difficulties with numbers come from and gives you some tests you can try on yourself or your friends to demonstrate them.
The biases discussed here and, in some of the other hacks in this chapter, don’t affect everyone all the time. Think of them as forces, like gravity or tides. All things being equal, they will tend to push and pull your judgments, especially if you aren’t giving your full attention to what you are thinking about.
7.2.1. In Action
How big is:
9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
How about:
1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9
Since you’ve got both in front of you, you can easily see that they are equivalent and so must therefore equal the same number. But try this: ask someone the first version. Tell her to estimate, not to calculatehave her give her answer within 5 seconds. Now find another person and ask him to estimate the answer for the second version. Even if he sees the pattern and thinks to himself “ah, 9 factorial,” unless he has the answer stored in his head, he will be influenced by the way the sum is presented.
Probably the second person you asked gave a smaller answer, and both people gave figures well below the real answer (which is a surprisingly large 362,880).
7.2.2. How It Works
When estimating numbers, most people start with a number that comes easily to mindan “anchor”and adjust up or down from that initial base. The initial number that comes to mind is really just your first guess, and there are two problems. First, people often fail to adjust sufficiently away from the first guess. Second, the guess can be easily influenced by circumstances. And the initial circumstance, in this case, is the number at the beginning of the sum.
Taken from : Mind Hacks
