Nav: Home

Your nose knows when it comes to stronger memories

June 19, 2019

Memories are stronger when the original experiences are accompanied by unpleasant odors, a team of researchers has found. The study broadens our understanding of what can drive Pavlovian responses and points to how negative experiences influence our ability to recall past events.

"These results demonstrate that bad smells are capable of producing memory enhancements in both adolescents and adults, pointing to new ways to study how we learn from and remember positive and negative experiences," explains Catherine Hartley, an assistant professor in New York University's Department of Psychology and the senior author of the paper, which appears in the journal Learning and Memory.

"Because our findings spanned different age groups, this study suggests that aversive odors might be used in the future to examine emotional learning and memory processes across development," adds Alexandra Cohen, an NYU postdoctoral fellow and the paper's lead author.

The impact of negative experiences on memory has long been shown--and is familiar to us. For example, if you are bitten by a dog, you may develop a negative memory of the dog that bit you, and your negative association may also go on to generalize to all dogs. Moreover, because of the trauma surrounding the bite, you are likely to have a better recollection of it than you would other past experiences with dogs.

"The generalization and persistence in memory of learned negative associations are core features of anxiety disorders, which often emerge during adolescence," notes Hartley.

In order to better understand how learned negative associations influence memory during this stage of development, the researchers designed and administered a Pavlovian learning task to individuals aged 13 to 25. Mild electrical shocks are often used in this type of learning task. In this study, the researchers used bad smells because they can be ethically administered in studying children.

The task included the viewing of a series of images belonging to one of two conceptual categories: objects (e.g., a chair) and scenes (e.g., a snow-capped mountain). As the study's participants viewed the images, they wore a nasal mask connected to an olfactometer. While participants viewed images from one category, unpleasant smells were sometimes circulated through the device to the mask; while viewing images from the other category, unscented air was used. This allowed the researchers to examine memory for images associated with a bad smell as well as for generalization to related images. In other words, if the image of a chair was associated with a bad smell, would memory be enhanced only for the chair or for objects in general?

What constitutes a "bad" odor is somewhat subjective. In order to determine which odors the participants found unlikable, the researchers had the subjects--prior to the start of the experiment--breathe in a variety of odors and indicate which ones they thought were unpleasant. The odors were blends of chemical compounds provided by a local perfumer and included scents such as rotting fish and manure.

As the subjects viewed the images, the scientists measured perspiration from the palm of the subjects' hands as an index of arousal--a common research technique used to confirm the creation of a negative association (in this case, of a bad smell). A day later, researchers tested participants' memory for the images.

Their findings showed that both adolescents and adults showed better memory specifically for images paired with the bad smell 24 hours after they saw these images. They also found that individuals with larger arousal responses at the point when they might experience either a bad smell or clean air while viewing the image, regardless of whether or not a smell was actually delivered, had better memory 24 hours later. This suggests that unpredictability or surprise associated with the outcome leads to better memory.
-end-
The paper's other authors included Nicholas Matese, Anastasia Filimontseva, and Xinxu Shen of NYU's Department of Psychology as well as Tracey Shi of Columbia University Irving Medical Center and Ethan Livne of the Weizmann Institute of Science.

This research was supported by grants from the National Science Foundation (CAREER Award Grant No. 1654393 and SBE Postdoctoral Research Fellowship Grant No. 1714321)

DOI: 10.1101/lm.048413.118

New York University

Related Memory Articles:

How long does memory last? For shape memory alloys, the longer the better
Scientists captured live action details of the phase transitions of shape memory alloys, giving them a better idea how to improve their properties for applications.
Seeing it both ways: Visual perspective in memory
Think of a memory from your childhood. Are you seeing the memory through your own eyes, or can you see yourself, while viewing that child as if you were an observer?
A NEAT discovery about memory
UAB researchers say over expression of NEAT1, an noncoding RNA, appears to diminish the ability of older brains to form memories.
Molecular memory can be used to increase the memory capacity of hard disks
Researchers at the University of Jyväskylä have taken part in an international British-Finnish-Chinese collaboration where the first molecule capable of remembering the direction of a magnetic above liquid nitrogen temperatures has been prepared and characterized.
Memory transferred between snails
Memories can be transferred between organisms by extracting ribonucleic acid (RNA) from a trained animal and injecting it into an untrained animal, as demonstrated in a study of sea snails published in eNeuro.
An immunological memory in the brain
Inflammatory reactions can change the brain's immune cells in the long term -- meaning that these cells have an 'immunological memory.' This memory may influence the progression of neurological disorders that occur later in life, and is therefore a previously unknown factor that could influence the severity of these diseases.
Anxiety can help your memory
Anxiety can help people to remember things, a study from the University of Waterloo has found.
Pores with a memory
Whether for separation processes, photovoltaics, catalysis, or electronics, porous polymer membranes are needed in many fields.
Memory gene goes viral
Two independent teams of scientists from the University of Utah and the University of Massachusetts Medical School have discovered that a gene crucial for learning, called Arc, can send its genetic material from one neuron to another by employing a strategy commonly used by viruses.
Neurobiology: The chemistry of memory
Learning requires the chemical adaptation of individual synapses. Researchers have now revealed the impact of an RNA-binding protein that is intimately involved in this process on learning and memory formation and learning processes.
More Memory News and Memory Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab