like a stereo to street traffic. I scored a 5.2. Adults average a 4, and
college students average a 3.5, which puts me in the 88th percentile of
sensitivity to noise. No surprise there. But in a short personality test, I
emerged as not too neurotic, and of medium agreeableness (and no
doubt more neurotic and less agreeable since moving to D.C.).
Next, I spit into a test tube to provide a reading of my pretest
cortisol levels. Now the real fun would begin. In order to tell if nature
sounds help “restore” subjects psychologically, Smyth has to first
stress them out. Public speaking and math tests are two of the most
dreaded tasks shared by a large number of people. So I was handed a
pen and some paper and told to prepare a short speech about why I
should be hired for my dream job. Partway through, my notes were
abruptly taken away from me and I was told to stand and deliver the
speech to a large mirror, behind which sat a panel of faceless judges.
Several times during the 5-minute speech, I was interrupted and told
to speak up. As I later discovered, this gauntlet of misery is called the
Trier Social Stress Test (and it often includes a mental math
component, typically repeatedly subtracting a number like 13 from a
four-digit number). I figured Trier must be some sadist who devoted
his life to freaking people out, but it turns out the test is named for
Germany’s University of Trier, where the test was formulated in
- It works: even though I knew there was no “panel of judges,” I
still showed a textbook response, with my heart rate climbing from
the mid-60s to the mid-90s during the speech, and my cortisol levels
(as revealed later) rising from 6.7 nanomoles per liter to 12.1. It’s
reductive to call cortisol a stress hormone, but lower levels generally
mean lower stress. Researchers tussle over how reliable a measure
this is (cortisol naturally varies over the course of the day, as well as
during the menstrual cycle, so researchers often use it to study men).
Next, Smyth randomly assigns subjects to one of three recovery
exercises: watching a fifteen-minute nature video with nature sounds,
watching a fifteen-minute nature video with nature sounds and