Sensory triggers of memory

Marcel Proust famously wrote in his semi-autobiographical novel Remembrance of Things Past published in 1913 how the smell and taste of a tea-soaked madeleine cake evoked the childhood memory of breakfast with his Aunt Léonie. The ability of sensory cues to bring back distant memories has since been called the Proust effect.  All of our senses can do this, but smell seems to be the most potent, enabling the retrieval of memories earlier in our childhood than any of the other senses.  Like many people with Alzheimer’s disease, I have completely lost my sense of smell and most of my sense of taste.  But my hearing is still good.  If I hear a song from my teen years, it will often take me back to memories of the past.

Starting in 2008 I made yearly trips to Tanzania to teach neurology to medical students and resident doctors at Kilimanjaro Christian Medical College in the foothills of Mt. Kilimanjaro. The local red-eyed dove (Streptopelia semitorquata) has a very distinctive, haunting call that immediately welcomed me on arrival each year.  A few years ago I was surprised to hear a very similar bird call while walking in our neighborhood in Portland, Oregon.  It evoked the feeling of watching the sunset on Mt. Kilimanjaro while drinking a beer on the veranda of my host’s home, a really nice feeling. I did some research and found that the Portland bird was a Eurasian collared-dove (Streptopelia decaocto), a fairly recent immigrant to the US.  Apparently fifty of them escaped from a pet store in the Bahamas during an attempted robbery in 1974.  By 1980 they had reached Florida, and by 1988 they were first seen in Oregon. On the Oregon coast now, I hear them almost every time I am there, far more often than I hear a mourning dove.  The Eurasian collared-doves seem to like to hide in the coastal pines.  They are very shy and have evaded my multiple attempts to get a photograph. Then last week I heard them calling from a tree right next to our cottage, and I was able to get an unobstructed photo without frightening them away. It is striking how much they look and sound like their African cousins, and for me they provide a wonderful link to two of my most favorite places filled with beautiful memories.