How Smells can Trigger Memories

Have you ever smelled fresh-baked cookies and thought about a childhood memory ? Or maybe you’ve smelled a campfire and were reminded of a trip to the lake.

This phenomenon is called olfactory memory, or the brain’s ability to recollect through odors. It’s part of the body’s limbic system, which controls emotions and drives.  Studies have shown that smells are significantly more effective than visual images at producing feelings of nostalgia and sparking specific emotional memories. In fact, smells have shown a remarkable ability to trigger elevated levels of brain activity in many settings. Here some facts about how our sense of smell interacts with our neurological impulses.

 

The Science

The first point of contact scents make with the body after entering the nostril is the olfactory bulb, which processes neural inputs and relays their information to the brain.

The olfactory bulb is a powerful center in the brain with many receptor cells in its makeup. It only requires the stimulation of a few receptors to create a sense of smell. In other words, a human’s sense of smell is very strong even for tiny amounts of odor.

Once smells have been properly identified by the olfactory bulb, they’re sent to two locations known as the amygdala and the hippocampus. These locations process smells on a higher level involving memory and emotion.

The amygdala, a set of neurons in the brain, starts to associate odors with positive and negative outcomes. it’s commonly discussed in reference to fear because of the way it trains the brain to recognize negative stimuli. The hippocampus continues this process, but does more to connect memories of specific occasions with particular smells. Over time, the brain’s neuron firing adjusts to the point where this associative process is common and second nature.

Audio, visual and tactile neurological responses do not pass through these areas, a common theory about why olfactory triggers are so powerful compared to other senses.

 

Memory

The primary result of this process is the brain’s ability to associate a wide range of smells with an equally wide range of memory triggers. These triggers exist on both the positive and negative ends of the spectrum, and become more sensitive based on the intensity of the memories involved.

Elements of the positive end are common in society. For example. many successful restaurants purposely cultivate a distinct smell to help drive repeat business. Unfortunately, negative memories can have just as strong a pull on the brain as positive ones, often stronger. People with major emotional trauma in their past – war veterans or PTSD sufferers, for instance – may experience a strong association with these painful memories via odor.

 

Emotions

Olfactory impulses aren’t limited only to memory, they can extend to emotions too. Memories trigger subconscious emotions, a phenomenon that takes place within the realm of smell.

Think of the aroma industry. Those perfumes and colognes on the shelf at your local designer outlet are designed to do much more than smell good. They’re also meant to trigger specific feelings, from attraction to relaxation to invigoration. They play on the way smell influences our attraction to potential mates, a documented phenomenon.

Loss of Smell

Also known as anosmia, the loss of smell can have major effects on emotion, memory and even overall health and longevity.

People who lose their sense of smell often experience emotional withdrawal, and can have trouble maintaining relationships. With such a major connector to emotion and memory removed, many feel a void they have trouble placing.

Of even greater concern is the link between smell loss and the potential early onset of dementia or Alzheimer’s disease. This link only helps confirm the strength of the relationship between smell and memory, but is of serious concern to those potentially suffering from these devastating illnesses.

 

Revere Health Neurology specialists treat patients with a variety of neurological disorders.

 

Sources:

• “Psychology and Smell.” The Fifth Sense. http://www.fifthsense.org.uk/psychology-and-smell/
• “DNA dating: has science unlocked the secret of a perfect match?” The Sunday Times. http://www.genepartner.com/uploads/press/95timesonline_240509.pdf
• “Smells Ring Bells: How Smell Triggers Memories and Emotions.” Psychology Today. https://www.psychologytoday.com/blog/brain-babble/201501/smells-ring-bells-how-smell-triggers-memories-and-emotions
• “Fear and the human amygdala.” National Center for Biotechnical Information. https://www.ncbi.nlm.nih.gov/pubmed/7666173
• “Decreased sense of smell may indicate early dementia.” Medical News Today. http://www.medicalnewstoday.com/articles/302665.php