According to psychologists, scents are the most powerful of triggers for memory. This happens due to the anatomy of the brain: the olfactory bulb, which processes scents in the brain, is located right next to the amygdala and hippocampus, which are the parts of the brain that control emotion and memory. There are no other senses whose signals pass through these parts of the brain. This means that the memories the we have that are attached to a particular scent are the most emotionally powerful memories that we have.
I have known this for years, but I got to experience it for the first time today. My fiance and I were shopping to buy me some new after shave, and she had me smelling different ones that had been sprayed on sample cards. I smelled one, and I had an immediate flashback. It was the most powerful and stunning memory that I have ever experienced.
A true out of body experience. In an instant, I was no longer standing in the store. I was standing in my boyhood home, I was 12 years old, and I was hugging my father. The smell of my father tickled my nose. The experience was complete: the smell, the sounds, the sights. I was once again a 12 year old boy who was hugging his father. My father has been dead for more than a decade.
I looked to my right at where I knew my fiance was standing, and I remember croaking out, "It's my father." Then I was back. the flashback was over, and it had only lasted for 2 or 3 seconds, but it was emotionally stunning. I broke out into tears, and it took me a minute or two to come to my senses and realize that it was not really happening. I left the store shaking.
This flashback was by far the most powerful memory that I have ever experienced, and it was all triggered by the smell of an aftershave. My fiance asked me if I wanted that one, and I told her no. I will be sure to avoid that one in the future.