4Manipulate Your Memory
You ever get ambushed by a memory? Like you're just sitting there, watching Magnum, P.I. reruns, and out of the blue you suddenly, vividly remember some completely unrelated event, like the day you spent at the zoo when you were 9, or something horrible that happened to you in kindergarten?
You didn't know it, but you smelled something that was connected to the memory. You can even use this to your advantage, strangely enough. If you smell a certain scent when you're studying for an exam, like say you are baking a pie while you read your notes, and then bring the smell back on exam day, like if you bring the pie with you, science says your score will improve.
Mmmmm ... fractal geometry.
And even if your instructor forbids pie in the classroom, your nose can still help you out: Being exposed to a particular smell while learning during the day, and then again while in a deep sleep that night, can improve your memory the next day.
The part of your brain that processes smell, the olfactory bulb, has strong physical links to the hippocampus and amygdala, brain areas that are heavily involved in memory formation and encoding. This close relationship means that while visual memories tend to decay quickly -- you'll lose 50 percent of them within months -- the majority of new smell memories will still be there a year later. So you can improve visual memories (like the ones you gained by reading) by associating them with a scent, like less attractive people latching onto good-looking friends in order to skip the line at a nightclub.
"Do NOT let the nose in. Last time he snorted all of our whiskey."
The trick works best if the smell you're latching onto is appropriate -- studies showed that people remembered book passages better when they read them in the presence of scents that "matched up" to the reading topic. So, the fragrance of blueberry pancakes might not be the best choice when you're studying for that History of Genocide test in the morning. And as for smell helping you when you sleep, we've said before that the brain uses deep sleep to encode memories that formed during the day, and it seems like this works even better when the brain is helped along by a nose-based reminder.
So, before dozing off on the night before the History of Genocide exam, instruct your roommate to fill the apartment with "genocide smells." Don't be any more specific than that -- the fun part is seeing what he comes up with.
3Change Your Moods
Maybe it's not a vivid memory that assaults you out of nowhere, but a feeling, or a mood. You're sitting there, minding your own business, when suddenly you're overcome with dread, or anxiety, or anger. Once again, there's a good chance a faint smell is at play, triggering your subconscious.
Fans of aromatherapy are always talking about "relaxing" scents, but the nose is actually way more useful when it comes to making you anxious, or alert. It works in a good way, too -- studies of "pupillary fatigue oscillations" (a sciencey way of measuring tiredness) found that people exposed to a peppermint scent stayed awake longer than those without it, and people given periodic doses of peppermint smells performed better on tasks requiring a high level of concentration.
"Goddammit, Steve, this looks like a two candy cane vault."
Bad smells not only decrease how well people do at complex tasks, but also have a negative effect as severe as you'd get from exposing people to a distracting noise. Well, duh, you say. So people couldn't concentrate because they were distracted by the stench. That's why it's so hard to study on public transportation! But the point is that the smells had the effect even when at such a low level that the subjects couldn't consciously detect them. We're telling you, it's like mind control over here.
"I'm sorry, but does someone in here have a full bladder?"
It's down to something called olfactory conditioning: You pair up a smell with something that causes a reaction, and later on that smell will cause a repeat of that reaction, even if the original cause is gone. And we're not talking about obvious things, like the way Rambo freaks out at the smell of napalm. You can actually change the blood glucose levels of diabetics by introducing a smell that you've paired up with giving them insulin in the past.
Like the smell of sugar if it's pressed into their nose, and they sniff really hard.
As for the feelings of anxiety, for whatever evolutionary reason, we are a lot better at detecting and remembering smells when we're in situations that feel dangerous, stressful or emotionally charged. Maybe it helped us remember the smell of bears.
Fun fact: An angry grizzly smells a lot like you pooping yourself.
But the connection between smell and emotion gets stranger still. Your sense of smell can actually ...