# Pseudorandom: a fascinating math game for 4+ players [#42]

A fun social experiment game with a very simple premise.

Choose a random number from 1-10.

Done? Let me try to guess which number you chose. Is it 7? If I'm right, you are *legally *obligated to share this article with one of your friends (just kidding). But surprisingly, most people aren't very random at all when asked to choose a random number. Take a look at this graph:

This graph is based on data from a professor asking over *8500 students *to choose a random number from 1-10. A whopping 28% of people chose the number 7, and barely anyone chose 1 or 10. What's going on here? Why is 7 such a popular number? Do people just really like 7?

Now that you've seen this graph, here's another question. You're standing in a room with 9 other people you've never met before. You and the others will all choose a number from 1-10, write it down on a sticky note, and then reveal your numbers at the same time. *If you choose a number that no one else chooses, then you win $100.*

What number would you choose?

That's the basis of the game *Pseudorandom*. It's a great social experiment game, and I'd like to share it with you today.

## Setup

You'll need the following materials:

- A sticky note and a pencil (with an eraser) for every participant
- One sheet of paper for every two participants (e.g. if you have 50 participants, you only need 25 sheets of paper)
- A Sharpie or marker
- A way to keep score (a whiteboard or computer works)
- Tape (even painter's tape works fine)

If you have N participants, you should have N/2 sheets of paper. Use a Sharpie or large-tip marker to write the integers 1 to N/2 on the sheets of paper (one number per sheet). Then tape those sheets to the floor in a sensible arrangement.

## Gameplay

Give each participant a sticky note and a pencil, and ask them to write their name on the sticky note. Let's assume that there are M sheets of paper on the floor, each displaying an integer from 1 to M. Then you can give them the following rules:

- 10 rounds will be played. In each round, a participant has the opportunity to win one (1) point. Whoever has the most points at the end of the 10 rounds wins.
- In each round, each participant will write a new integer from 1–M on their sticky note. (They can erase their previous number.)
- Then, after every participant has written their number, they will stand on the paper containing their number.
- If a participant is standing
*alone*on a sheet of paper, then they win one (1) point, because they picked a number no one else picked. - If a participant is standing with
*at least one other person*on a sheet of paper, then they do not win a point (because they picked a number that someone else picked).

- If a participant is standing
- Participants are
*not*allowed to 1) look at other people's sticky notes while they are writing on them or 2) stand on a number different from the one they've written down. - Participants
*are*allowed to 1) talk to fellow participants about the game and 2) team up with other players.

## Strategy

There are a few main strategies that emerge in *Pseudorandom*:

- Dwayne "The Rock" Johnson: Picks the same number every time. Actually a reasonable strategy, because anyone else who picks that number won't get points.
- The Opportunist: Randomly chooses between the numbers that weren't chosen much last round. Not a bad strategy, but there are typically many opportunists in a typical game of
*Pseudorandom*. - The Real Estate Agent: Randomly chooses between the numbers that
*were*chosen most frequently last round. As they say in the business: location, location, location. If a lot of people like a number, it's worth it to establish a presence there. - The Mathematician: Uses his phone to randomly choose a number each round. He or she thinks that
*true*randomness is the best way to win a game based mainly on psychology.

Which strategy do you find yourself using?

## Conclusion

*Pseudorandom *is a pretty fun game! I hope you enjoyed my writeup — and perhaps you'll be inspired to host a game of *Pseudorandom *for your friends.