So there are a number of brief, on-the-spot games I play with the kids between instruction or projects. We play a variety of hangman, a sort of game like Mastermind except with words, four-in-a-row team tic tac toe, equation solving tic tac toe, and so on.
One of these games is What Do They Have in Common; in this game I ask several kids to stand up, and the class takes turns trying to guess what characteristic belongs to that group, and only that group. The simplest example of this would be: all the girls stand up. A slightly harder example is: asking the kids in striped shirts to stand up. A very hard example might be: have the kids whose names begin with vowels stand up.
In general, kindergarten kids are not very good at this game. The first day I introduced the game, after the more obvious boys/girls and hair color examples didn't go exactly smoothly, I had my assistant and I stand up and all the kids sit. They had a very hard time coming to conclusion that what we had in common and they didn't was "adulthood" or "are teachers" or anything of that kind.
The kids will excitedly and erroneously proclaim the current round's characteristic to be the same as the previous, even when it is clearly not ("no, not all the girls are standing up this time, so that can't be it..."). They will attempt to conflate it with patterns ("there's a girl, and a boy with shoelaces, then a girl, and boy without shoelaces"), which is pretty much the opposite of the idea. They are also largely incapable of figuring out abstract common themes, such as "everyone standing has a double letter in their name." And, finally, when asked to come up with their own characteristics to form a group, usually miss one person who fits the condition, or put in an extraneous one ("A2 is standing up, but he isn't wearing any buttons!").
In short, it's great fun. They're getting better at it. And to be fair, it's a pretty hard game. Today I could not figure out a couple of the characteristics that the kids thought of themselves (everyone with collars, with brown eyes). On the other hand, one of the kids standing up in the former game was not actually wearing a collar. So that made it a bit tougher.
So but anyhow this morning I had the three kids whose names end in Y stand up. There were a couple of desultory guesses, then A3 raised her hand eagerly. "What do you think these three classmates have in common?" I asked her.
"They're all very slow in finishing their work!" she said gleefully.
Cue: Assistant and I convulsing with laughter, amid faux-horrified protests at the idea.