Why is it, that we’re incapable of smelling our own houses?
Turns out, it’s your brain’s fault.
THANKS A LOT, BRAIN.
Hey guys, Tara here for Dnews - and have you ever arrived home from vacation, only to have
your nostrils assaulted as soon as you open the door?
“Why does my house smell so bad?”
you might say, as you furiously scramble to find the source - but what you may not realize,
is that maybe your house always smells bad.
Maybe you don’t notice it, because you’ve gotten used to it - which is an even more
terrifying thought.
But it turns out, that’s exactly what happens.
It’s called “sensory adaptation,” and Pamela Dalton, a cognitive psychologist at
Monell Chemical Senses Center, has devoted decades of her career to studying this phenomenon.
She explains it, by using the example of a chemical air freshener.
When you first start to use one, the odor molecules travel through your nose and hit
your odor receptors, which then send signals up to your olfactory bulb in the brain’s
limbic system.
This is the part of your brain associated with emotion and behavior, but it’s also
used to detect incoming threats.
Obviously, a chemical air freshener poses no threat, and your brain recognizes that,
so almost immediately, it starts to switch off the receptors in your nose - and that’s
why the intensity of the smell starts to fade quickly.
But why does this happen?
Is it to preserve resources?
Well, we’re not exactly sure.
But the leading theory, is that by adapting to the smells in our environment, it allows
us to quickly detect new changes, that could be potentially threatening.
So if your house was musty, for example, and that was all you ever smelled - then you might
be unaware if something else in your house, started rotting.
It makes sense from an evolutionary standpoint - but then why is this phenomenon exclusive
to our sense of smell?
It’s not like staring at something for a long time, makes you go temporarily blind.
And yeah, you can start to tune out noises after a while - but if somebody comes up to
you and starts talking, you immediately snap out of it.
With smells, though, you can’t really do that - once you’re used to the way something
smells, the only way to actively detect it after a while - is to leave the area and come
back.
Interestingly, though, there is another way to slow down the adaptation process, and that’s
physical activity - or really, anything that increases blood flow.
Dalton points out that scientists who work at perfumeries - will sometimes run and up
and down stairs, to regain their sense of smell.
Although perfumery is probably one of the few careers where you’d need to actually
smell things all the time, it is worth noting that being overly concerned about smells - can
actually make you more sensitive TO them.
In her interview, Dalton recalls a study in which she exposed 3 groups of people to the
same scent - telling the first group it was a “rainforest extract,” the second group
that it was a standard scent used by her lab, and the third group, an industrial solvent.
Sure enough, the people who thought they were smelling industrial solvent, were also the
slowest to adapt to the scent.
Which coincides with the fact that we adapt to smells we consider non-threatening.
It really is quite amazing, just how efficient the human body is.
And speaking of the human body, let me remind you all that I host another show here on Discovery
called Anyhoo, and wouldn’t you know - I just recorded an episode about scientists
successfully calculating the ideal proportions for various body parts.
So if you ever wanted to know what a mathematically perfect belly button looks like - then click
here.
And in the meantime, let us know what you think of this episode in the comments below.
Otherwise, thanks for watching!