Rachel Herz explores the psychology of scent
When uncapped, they reveal only clouds of cotton balls, but the scents they
release are meant to cut through a cloudy mind and stir up memories. They
include smells such as suntan lotion, crayon, Vicks VapoRub and baby powder -
frequently encountered during childhood and not much thereafter.
Herz (left), a visiting professor of psychology, studies the connection between odors
and memory, and recently published an account of her work, titled "Scents of
Time," in The Sciences. She came to Brown in July, following in the research
path of intellectual mentor and professor emeritus Trygg Engen.
"If asked a few years ago where I'd like to be, I'd say at Brown, where Trygg
was," said Herz, of the man who wrote "The Perception of Odors." "In such a
small field, this is really the nucleus."
People generally do not give much thought to their sense of smell beyond the
pungent odor of a skunk or of bread baking. Given the choice to lose a big toe
or the sense of smell, said Herz, the responses are split down the middle.
Given the choice to lose a big toe or sense of sight, however, there would be
no question: People would choose the big toe, she said.
But those who lose their sense of smell because of accident or illness also
report a loss of emotional richness and, over time, a loss of emotional
intensity toward life, according to Herz. Experiences are flatter, they
report.
Herz studies many components of scent-triggered memories. How does the
emotional intensity of reaction to a scent compare to the emotional intensity
of a memory triggered by a visual cue or word? How accurate is a memory
triggered by scent, and how does context influence the perception of odors?
Researchers know that odors don't trigger memories that are any more accurate
than the memories triggered by other stimuli, but odors do trigger memories
that are more emotional.
For example, a person may have no emotional reaction to seeing a photo of a
loved one who died. But that person may unexpectedly encounter the same smell
particular to the loved one's study - a combination of cigarettes and books,
for instance - and feel like weeping, said Herz.
"We often don't encounter certain odors frequently," said Herz. "In some way
you are potentially more vulnerable to odors ... and taken unaware."
Perhaps an occupational hazard, Herz has become very aware of smells. And she
likes a variety of them - some admittedly not as popular as others - such as
the faint scent of skunk. Part of the reason may be that Herz first encountered
the smell as a child while driving through the country with her parents, and
was not given any cue that it was a negative smell.
Her example supports the idea that odors are learned; a woman once told Herz
that she hated the scent of roses because she first smelled it at her mother's
funeral.
Researchers have found cultural differences in responses to scents. While
Americans generally enjoy the scent of wintergreen, which is found mainly in
candy in the United States, the British find it unpleasant. To an older
generation of British citizens, it smells like medicine, particularly an
analgesic rub popular during World War II - an obvious negative association.
A biological reason why people may not like some odors is the presence of a
trigeminal component, which irritates the nasal lining. But little is known
about the variability in sensitivity to odors among people. For example, Herz
said, perhaps she is not sensitive to a certain component of skunk odor that is
apparent to those who have a negative reaction to the odor.
One of the hardships of this line of research is that smell is a difficult
variable to control in the laboratory. The exact amounts of odor presented to
subjects via the little white jars must be controlled in ways that are
reproducible, according to Herz, whose lab is nearing completion.
In the few months before she landed in her current office in the Hunter
Psychology Lab on Waterman Street, Herz floated around to a few temporary spots
- including Trygg Engen's office. Did it have any particular smell? "The smell
of books."