I opened Monday’s class by splitting my 150+ students into pairs for a few Schelling games. (Seventy-five pairs can be noisy.) To win at a Schelling game, all you have to do is guess the same thing that your partner guesses. And of course, they’re trying to guess the same thing you are. For example, if you can choose between heads or tails, which should you choose? You guessed it — almost everyone chose heads.

Schelling games are relevant to linguistics. Herbert Clark points out that dialogue works because there’s a tendency for people to try and coordinate their activities together using talk. This is true even when you’re working with someone you may not know well. You may not share much common ground with them, but you can still rely on a kind of garden-variety context.

The second round was ‘pick a number’. Here are the choices: 7, 13, 99, 261, 555. Which would you pick if you were trying to match someone who was trying to match you?

People who won tended to pick 13, although there were some interesting other answers. One pair won with 261.

“You both picked 261?” I asked. “That’s rather surprising.”

“We’re brother and sister!” they said.

Which made Clark’s point rather nicely. People who have no common ground will fall back on normal-seeming answers if they want to agree, but when two people have a lot of shared knowledge, unexpected things can take on a salience of their own.

Let’s try a Schelling game now. You win a free trip to any city in the world, but only if you choose the same city that your partner does. And your partner is me, and I’m trying to guess what you’ll guess. My answer is in comments.

When people learn that I’m a linguist, they sometimes imagine that I am an Official Grammar Arbiter. They say things like “Oh, I hate when people say ‘That was fun.’ Don’t you hate that?” Leaving me to wonder why they’d pick on that poor, innocent, perfectly acceptable sentence. Or something equally innocuous. It would be one thing if they’d complain about something ambiguous like ‘downwards’ instead of ‘downward’ or ‘if I were/was’. But it’s often some ordinary sentence that anyone would say.

Last night, a gentleman told me, “I’ve become more tolerant about grammar since reading the history of English.”

“Oh, really?” said I.

“Yes, I used to hate when people would say ‘That’s so great, or so interesting.”

“Um,” said I.

“But now I realise that English has been changing for a long time, and the English we use was once unacceptable. So I’ve become more tolerant about it.”

“That’s good,” said I.