When one thought sets off a chain reaction until a person thinks about something completely unrelated to the original thought.
1: I thought about our trip to Santa Monica which reminded me of the hobos everywhere which made me think of soup kitchens which made me want to go to get some miso soup.
2: You just went from "Santa Monica" to "Miso Soup..."
1: Domino thoughts...
When someone says something and you think about it. Then one thought leads to another leads to another, until you’re thinking of something way off topic.
friend: "christmas is almost here."
you (thinking): "it is isn't it? I bet the stores are packed. I wonder when I should go christmas shopping...maybe when I do I should get myself new pants, since all of my pants are ripped.."
you (outloud): "have you ever noticed that I have holes in all my pants?"
you: "sorry...domino thought"