Why Does This Jacket Smell Like Childhood??!!

You are packing again for summer camp, and frantically searching for the huge suitcase reserved for these two week long excursions. After finally spotting it in a dusty corner of your basement, you lug the giant purple suitcase up two flights of stairs and into your room. Finally ready to start packing, you unzip the suitcase and whip open the cover. With one inhale, everything from last summer at camp comes rushing back--you remember the cabin chats, the ropes courses, the friends you made, and the s'mores you roasted. Woah. Your first thought is excitement and longing to return to camp, followed by confusion as to what just happened. Was it magic? Was it the universe telling you that you will have a great time at camp? The answers to both of these questions is no. This experience was purely driven by science.

A Thought That Must Be Going Through Your Head Right Now

To begin explaining this incredible phenomenon, we must first understand brain anatomy. When a smell enters the body through the nostrils as odorant molecules, the molecules dissolve into the mucus in the nasal cavity and bind to a receptor with a socket perfectly shaped to fit the molecule. This all happens in the cilia of dendrites located on bipolar neurons. The attachment of the odorant molecule results in action potentials that navigate the olfactory bulbs on their way to the thalamus, the limbic system, and lastly to the temporal lobes where the scent is interpreted and integrated. To better understand neuron structure and function, click here.

Diagram of the Nasal Cavity and Olfactory Bulb

The olfactory bulb extends from the nose to the bottom of the brain. It directly connects to the amygdala and hippocampus. The hippocampus is the place where short-term memories are stored, and the amygdala is responsible for the production of moods and emotions. Like peanut butter and jelly, these two parts of the brain work together to produce something magnificent--memories and emotions generated solely from smell. Scent is very unique when it enters the brain because it is one of the only senses that has connections to the hippocampus and amygdala. Auditory, tactile, and visual information do not pass through these parts of the brain. Taste functions in a similar manner as smell, given that the taste cortex (takes in and processes taste) is connected to the hippocampus.

 Diagram of the Regions of the Brain Involved in Interpreting Olfactory Information

Intrigued and curious about this process, I decided to conduct an experiment using my peers as guinea pigs. I covered one cotton ball with CVS Kids Clear Spray Sunscreen, and another with CVS Baby Powder. I asked every participant to close their eyes, smell the cotton balls one at a time, and immediately write down what came to mind when smelling the scents. 

The best part of this investigation was seeing the incredible reactions each participant had to the scents. I counted every instance a classmate mentioned a certain memory, so these numbers do not add up to the total number of people interviewed. For the sunscreen, seven out of the twenty people participating said that the scent brought them back to the beach, six said it reminded them of a particular summer day, three of them remembered their childhood, and five had other, abstract experiences. These results were exactly as I expected, given that this type of sunscreen is primarily used in the summer, at the beach, and during childhood. 

CVS Kids Clear Spray Sunscreen

The baby powder, on the other hand, did not reap the results I expected. The reason for this is primarily my fault for not using baby oil instead (it soaks into the cotton ball more easily) but also the participants' faults for breathing too hard and inhaling all of the powder. Only two of the twenty interviewees were reminded of an experience with babies, four remembered childhood, nine felt nothing, three were brought back to a sweet time baking or sniffing sugarcane, three remembered doing laundry, and two had other, very different experiences.

CVS Baby Powder

In the end, after awkwardly asking strangers to smell my mysterious scents, the beauty of the human brain is majestically evident. It is unbelievable how simple molecules can trigger memories thought to be long forgotten.

Super helpful and awesome links!!!:

American Association of Family Physicians 

Making Sense of Scents Article

Psychology and Smell Article

How Smell Triggers Memory and Emotion