Why smells trigger your memories

There is no doubt that smell is a potent source of memory. It has been confirmed in laboratory experiments where researchers test subject’s response to certain cues.

You open a packet of biscuits, releasing a faint sweet, processed aroma you barely recognise and suddenly you are a six-year-old again in your great aunt’s house. You haven’t thought of her in years, but now the smell reminds you of her faded Persian carpet, her porcelain horses and even the polka dot dress she was wearing as you pinched custard cream biscuits off her best china plate.

The biscuit smell alone has been enough to take you back deep into your memories. Why?

According to Dr Adam Osth, lecturer at the School of Psychological Sciences at the University of Melbourne, the reason smells are so effective in evoking memories may be because we aren’t good at smelling.

“We have a lot of complex processing in our other senses where we make associations and recognise similarities, which helps us to navigate around the world. But it also means that it is easier to confuse things and that produces interference and forgetting,” says Dr Osth, who is in the faculty of Medicine, Dentistry and Health Sciences.

Smell may be so effective in evoking our memories because it is so simple. Picture: Crazy House Capers/Flickr.Smell may be so effective in evoking our memories because it is so simple. Picture: Crazy House Capers/Flickr.

“One possible reason why smell is very powerful at evoking memories may be because we simply aren’t very good at it compared to our other senses. When we smell we can only process odours as being very distinctive from each other.”

It means that because we don’t have the processing power in our brains to notice subtle differences between smells in the way animals like dogs can, smells are more distinctive and are therefore possibly easier to remember.

Smell works

There is no doubt that smell is a potent source of memory. It has been confirmed in laboratory experiments where researchers test subject’s response to certain cues. For example, when using words as cues a common response to “girl” is “boy”.

“Studies have found that odours are extremely effective cues at promoting memory and they prompt much longer term memories than other types of cues,” says Dr Osth.

The bigger question is why? We don’t know the reasons for sure, but it may be to do with the way we use associations to understand the information we take in from our senses.

Our brains have highly developed processing power for senses like sight and hearing, but are more primitive when it comes to smell. Picture: A Health Blog/Flickr.Our brains have highly developed processing power for senses like sight and hearing, but are more primitive when it comes to smell. Picture: A Health Blog/Flickr.

“Everything from your environment that you sense you associate together. So when you have a memory it is because something has reminded you of something else,” says Dr Osth.

But while associations are important in helping us to interpret our world, the downside is that as more associations are stored up in our brains, the greater the possibility that different associations will overlap and be mixed up. Scientists call this interference and it is one of the explanations for why we forget.

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You open a packet of biscuits, releasing a faint sweet, processed aroma you barely recognise and suddenly you are a six-year-old again in your great aunt’s house. You haven’t thought of her in years, but now the smell reminds you of her faded Persian carpet, her porcelain horses and even the polka dot dress she was wearing as you pinched custard cream biscuits off her best china plate.

The biscuit smell alone has been enough to take you back deep into your memories. Why?

According to Dr Adam Osth, lecturer at the School of Psychological Sciences at the University of Melbourne, the reason smells are so effective in evoking memories may be because we aren’t good at smelling.

“We have a lot of complex processing in our other senses where we make associations and recognise similarities, which helps us to navigate around the world. But it also means that it is easier to confuse things and that produces interference and forgetting,” says Dr Osth, who is in the faculty of Medicine, Dentistry and Health Sciences.

Smell may be so effective in evoking our memories because it is so simple. Picture: Crazy House Capers/Flickr.Smell may be so effective in evoking our memories because it is so simple. Picture: Crazy House Capers/Flickr.

“One possible reason why smell is very powerful at evoking memories may be because we simply aren’t very good at it compared to our other senses. When we smell we can only process odours as being very distinctive from each other.”

It means that because we don’t have the processing power in our brains to notice subtle differences between smells in the way animals like dogs can, smells are more distinctive and are therefore possibly easier to remember.

Smell works

There is no doubt that smell is a potent source of memory. It has been confirmed in laboratory experiments where researchers test subject’s response to certain cues. For example, when using words as cues a common response to “girl” is “boy”.

“Studies have found that odours are extremely effective cues at promoting memory and they prompt much longer term memories than other types of cues,” says Dr Osth.

The bigger question is why? We don’t know the reasons for sure, but it may be to do with the way we use associations to understand the information we take in from our senses.

Our brains have highly developed processing power for senses like sight and hearing, but are more primitive when it comes to smell. Picture: A Health Blog/Flickr.Our brains have highly developed processing power for senses like sight and hearing, but are more primitive when it comes to smell. Picture: A Health Blog/Flickr.

“Everything from your environment that you sense you associate together. So when you have a memory it is because something has reminded you of something else,” says Dr Osth.

But while associations are important in helping us to interpret our world, the downside is that as more associations are stored up in our brains, the greater the possibility that different associations will overlap and be mixed up. Scientists call this interference and it is one of the explanations for why we forget.

By Andrew Trounson