floor a few feet from a wall has a hol-
low quality because of slight echoes
that immediately follow the original
click of contact. The echoes from
the stick tapping the floor follow
too quickly to distinguish as distinct
replicas of the original click, but they
add slightly to the original click sound
nonetheless.
If you tap the stick closer to the
wall (within a few inches), the click
will have a somewhat higher pitch.
Some people report that clicks right
next to the wall sound “deader” be-
cause they contain fewer echoes and
overtones.
4
See Behind You
Sound shadowing is a close
cousin of echolocation. It lets
you sense when someone—or a large
something, such as a predator—is right
behind you, even when that someone
(or something) makes no sound.
Stand with your eyes closed on a
carpeted surface (or another sound-
deadening surface, such as grass or
beach sand), and have a friend sneak
up behind you so that you don’t
hear his or her footsteps, breath-
ing, or clothes rustling. The experi-
ment works best when you have a
psychologytoday.com (june 2018), copyright © 2018
by eric haseltine.
conspicuous sound source, such as a
radio, located about ten feet behind
you to create background noise.
As your friend approaches from
behind, even though you can’t see or
hear him or her directly, you should
be able to “feel” the person’s proxim-
ity by the sound shadow that he or
she casts—the way the person blocks
the sound. If you pay close attention
to the sound shadow, you’ll perceive
it has two parts: a slight lowering of
volume and a deadening of echoes
of the radio noise off surfaces be-
hind you. These two effects become
increasingly obvious as the person
gets closer to you. Our unconscious
ability to sense that someone is be-
hind us may have given rise to that
overworked phrase in thrillers and
mysteries: “She felt someone watch-
ing her.”
Although the perception of sound
shadows, like echolocation, is yet an-
other example of implicit memory, it
may also have a hardwired survival
component that helps us fill in a large
blind spot behind us that predatory
animals (and nasty humans) could
otherwise exploit.
Mazel Tov!
I’d like to think that halfway through Nicole Kidman’s
last name, there’s a tiny bar mitzvah.
@justinshanes
rd.com 119
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