Why Can’t You Smell Your Own Home?

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Photo: Renold Zergat/Getty Images

Everyone’s place has a smell. Some homes smell like fancy perfume or Anthropologie candles; others smell like cats. Currently, there’s a Febreze ad campaign that seizes on this idea — that although you’ve gotten used to the odors in your own home, your guests think your place stinks like a high school boys’ locker room or an oversize, smelly sneaker. But what accounts for this “nose-blindness” and is there a way to fight against it? 

To find out, Science of Us spoke to Pamela Dalton, a cognitive psychologist at Monell Chemical Senses Center, who has been studying this very question off and on for more than two decades. “It’s actually a very robust phenomenon,” she says. “It’s why people go on vacation and come back and say, ‘Oh, it’s so musty in here — I’d better open some windows!’”  Maybe your house is musty — but according to Dalton, it’s also possible that that’s what your house always smells like, but you just don’t usually notice it.

How does this happen?
First, let’s talk about what’s happening inside your nose and brain when you “get used to” environmental smells. At home, say you have a new cinnamon-scented air freshener. When you first start to use it, the odorant molecules waft through your nose and hit your odor receptors, which then send signals to your olfactory bulb in the brain’s limbic system, which is associated with emotion and behavior. There, your brain identifies the odor and decides what to do about it.

But very quickly — after just about two breaths — “the receptors in your nose sort of switch off,” Dalton says, and the intensity of the smell starts to fade. That’s because your brain has perceived the scent to be nonthreatening, which means there’s little need to pay close attention to it.

Dalton describes a study in which she gave people an air freshener dispensing a pleasant, pine-y smell to put in their bedroom for three weeks. “Every week, they became less sensitive to the odor,” she said. “They would ask me, ‘Are you sure it’s still working?’”

Why does this happen?
Scientists aren’t exactly sure why our noses adapt to smells, but it seems to be because it helps us to very quickly detect even the subtlest change in the scent of our environment. For our ancestors, this function might’ve helped them notice a change in smell in some animal they’d killed, signifying that the corpse was rotting and not safe to eat, Dalton explained. “Whatever is new in your environment, that huge signal rises above the rest,” she said. “So it makes you an expert in change in your own home.” 

Is there anything you can do to “refocus” your brain, so it does pick up those environmental odors?
This phenomenon is known as sensory adaptation, and it’s something we experience most intensely with smells. “That’s not as true for any other sensory experience,” Dalton said. The closest comparison, she says, is hearing. If you’re working near a construction site, for example, you can tune out the noise after a while. “But if I ask you, ‘Do you hear that?’ you can refocus that part of your brain. That’s not so true with odor,” Dalton said.

So is there any way to get better at picking up on smells in your environment? Kind of. Dalton says that most of what scientists know about how to better set up your nose to respond to smells is borrowed from perfumers. For one, taking frequent breaks help — as you already know, coming back home after a long time away is your chance to experience your home’s smells like a guest would. Increased blood flow also seems to help the nose start smelling those familiar scents again; Dalton says that some perfumers run up and down stairs to perk their weary noses up, and that she’s found this idea works in her lab, too.

But if this is something you’re worried about, here’s some good news: Being overly concerned about smells actually seems to make your nose more sensitive. Dalton recalls a study she did once in which she exposed three groups of people to the same scent; she told one group the smell was a “rainforest extract,” another group that it was just a standard scent frequently used by her lab, and the third that it was an industrial solvent. The group who was told the scent was solvent — that is, something negative — were the slowest to adapt to it.

“So fear seems to interfere with that psychological process [of sensory adaptation],” she said. And, yes, she said the “fear” of having a gross-smelling home also, probably, counts. In other words, if this is something you’re worried about, you’re probably fine. But you can also always do some quick jumping jacks, just to be sure.