Your Nose Can Hijack Your Brain

Listen to a podcast interview on this topic with a smell expert on our very first podcast right here!

Smell is one of your most powerful senses. Five percent of your DNA is dedicated to it. The smells in your environment affect you constantly, and often, subconsciously. But you don't have to take in odors passively: in fact, you can actually use scents to affect your own state of mind and the perceptions of those around you.

The Nose Knows

Humans can detect at least one trillion different smells. That puts your vision and hearing to shame. Your eyes can discern several million colors. Your ears can only pick up half a million tones. Smell associations are formed before birth. When mothers ate garlic or smoked during pregnancy, their babies preferred those scents after birth. Given those powerful connections and specific perceptions, it makes sense that the smells around you can literally alter your behavior.

According to Dr. Alan Hirsch, a neurologist and psychiatrist who specializes in the treatment of smell and taste loss, you can expose yourself to certain smells to achieve a variety of positive effects. For example, if you want to study better: "in the presence of a mixed floral smell, 84 percent of the time there's an increase in the speed of learning compared to when there's no odor."

Odors can also affect a person's spatial perception. In a study measuring peoples' brain waves, heart rates, and other factors, Dr. Hirsch concluded that "in the presence of green apple smell and cucumber, people perceive a room as larger. In the presence of barbecue roasted meat, they perceive the room as smaller.

"If you have to sell your house and you want people to think a room is bigger than it is, then you can add the scent of cucumber or green apple to the room, and people will perceive that it's larger. Or if you have to go on an airplane and you can't stand being in small seats, then take some cucumber smell or green apple smell, and your perception will be that it's a larger space."

The effects of smell can also impact your behavior toward others. People exposed to the smells of baking cookies or roasting coffee are more inclined to help a stranger than people not exposed to an odor manipulation.

Nose No-Nos

Just as odors can have a positive impact on us, they can also produce negative effects. "Some odors - for instance, jasmine and trigeminal stimulants like citrus and peppermint - tend to produce anxiety in people, and malodors enhance anxiety," Dr. Hirsch explained. "When you're in a bad smelling place, you become more anxious and you become more aggressive or angry. On days when there's a bad smell and air pollution, there's an increased number of motor vehicle accidents, suggesting drivers are driving more aggressively."

Dr. Hirsch has also studied the effects of odors on our perception of time, hand-eye coordination, and even male and female sexual arousal. To learn even more about how odors affect our behavior, listen to our conversation with Dr. Alan Hirsch on the Curiosity Podcast. Stream or download the episode using the player below, or find it everywhere podcasts are found, including iTunes, Stitcher, and Gretta.

How Many Smells Can You Smell?

Key Facts In This Video

  1. Smelling is an essential part of your genes. 00:42

  2. People rate memories triggered by smell as more emotional than by sight or sound. 02:17

  3. Smells can occur in the womb before we're born. 02:41

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Written by Cody Gough July 21, 2017

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