Everybody has had the thought: “How is my partner/roommate/child/parent/friend so oblivious to this huge hot mess?!” But before we judge them, we have to talk about habituation.

People really do stop seeing a mess after a while. This invisibility isn’t neglect, it’s neurological. Our brains are always on the lookout for new and unexpected information, an adaptation that was particularly useful when we had to notice the predator slinking through the grass and the fruit ripening on the vine.

But the flipside of being attuned to novelty is being unaffected by sameness. That’s called habituation: we might have had a strong response to a stimulus at first, but, over time, our response will be less intense after repeated exposure to that stimulus.

We might have noticed when a pile of our shoes built up by the door, and we might have felt bothered by it. But if the pile remained day after day, week after week, our brains would become habituated to that sight and we’d feel very little about the pile, if we even registered it’s presence at all.

That mess only becomes stimulating again when we see it in a photo we snapped of our space, or when we imagine how a guest to our home will experience it. Nothing like inviting people over to shake us out of our habituation.

The good news is that once we get our house in order, we’re habituated to clear surfaces and tidy storage, and then even a small mess is very novel to our brain. We notice it, we respond strongly to it, and we can tackle it then and there, before it fades from our awareness.