The Smell of a Book

There's one part of the human brain that seems programmed to never forget things. It's somewhere in the limbic system, and it connects smells to emotions. This past week, deep in the bowels of New York Penn Station, that part or my brain was momentarily triggered by an acrid smell. Perhaps it was smoking train brakes or hot diesel oil, but it evoked a sad memory from ten years ago.

Smells connect us across decades, maybe across millennia. Some smells are hardwired to be pleasant or noxious, other smells are neutral and imprintable. Think of the smell of a new-born baby or the smell of your grandmother. Think of the smell of Starbucks, or of bread baking in the oven at home. Imagine being in a damp cave, or a medieval cathedral.

Scientists have studied this. It's now thought that the primal connection between smell and memory is a result of direct connections between our olfactory lobes and the hippocampus. Some scientists in Israel used functional MRI to see directly the involvement of the hippocampus in memories imprinted with strong smells. (Notes 1 and 2 and the picture.)

It's odd that so many people claim to love the smell of books. It's even stranger that people claim to love the smell of libraries or used bookstores. It's just old glue, ink, dust, mold, and decay. Odd, until you think about the time-travel aspects of smell.

In preparation for the upcoming launch of Unglue.it, I've been talking to a lot of people about the books that they love. "Love" in this context is not the "love" people might use casually to describe their relationship with a product for sale. Instead, people seem to relate to books the way they relate to people. There's the love for a teacher who makes a difference in your life. Love for a friend you helps you feel joy. The thrill of discovering a soul mate. And among authors, there's the blind love for a child that goes beyond all rationality.

The intensity of these emotions must get bound up with smells in the hippocampus to create a lasting impression on book lovers. When we smell a book all of these feelings resonate across time and they comfort us. Even in the future when all our reading is done on ebook readers or other screens, we'll keep real books around us like the clothing of a spouse or a parent lost to a tragedy, left in the bed to warm and comfort. And then we'll find strength to move on, but the spirit of the book will remain.


Notes:

1. Jonah Lehrer's article on the Israeli fMRI study is very accessible.
2. That study, "The Privileged Brain Representation of First Olfactory Associations" was written by Yaara Yeshurun, Hadas Lapid, Yadin Dudai and Noam Sobel in Current Biology 19(21), 1869-1874, (9 November 2009) and is available at http://www.cell.com/current-biology/abstract/S0960-9822(09)01857-0
3. Another human sensation mediated by the hippocampus is laughter. I suffered repeated bouts of this affliction upon reading a website claiming to promote an aerosol spray. I was almost unable to finish this post.