To the average observer, it would
seem that 44-year-old patient
"SM" was just another typical
mother of three: she scores
normally on IQ tests, has good
language skills and a decent
memory. But, according to a
paper by neurologists at the
University of Iowa, SM is
profoundly unusual. Because of a
degenerative condition that left
her with damage in certain brain
structures, researchers say, SM is
incapable of feeling fear.
The researchers know, because
they spent several days trying to
scare her silly. They exposed SM
to snakes and spiders at a pet
store, showed her clips of horror
movies like The Shining and The
Blair Witch Project, and took her
through a haunted house in a
former sanatorium. SM's fear
response? Nonexistent.
In fact, she relished cuddling
snakes and had to be stopped
from reaching for a tarantula.
SM has a genetic condition that
has disabled, in both
hemispheres, a brain region
known as the amygdala, which is
involved in processing emotional
memories and fear. She has been
studied by neurologists for 20
years because her case is so
extreme, and has so far been
shown to be unable to read
social situations that involve fear
or to recognize evidence of fear
on the faces of others.
SM says that she hasn't felt afraid
since a childhood incident
involving a snarling Doberman
pinscher. The research team —
including Justin S. Feinstein, Ralph
Adolphs, Antonio Damasio and
Daniel Tranel — theorizes that
her condition hadn't yet
destroyed her amygdala at the
time. But what's more interesting
is her life experience since then,
which has often been frightening
and dangerous. Her lack of fear
has many times caused her to
place her own life in danger. The
authors write in their case study,
published on Dec. 16 by the
medical journal Current Biology:
As it turned out, SM has
encountered numerous
events that would be
considered fear-inducing or
even traumatic in nature. For
instance, she has been held
up at knife point and at gun
point, she was once
physically accosted by a
woman twice her size, she
was nearly killed in an act of
domestic violence, and on
more than one occasion she
has been explicitly
threatened with death.
What stands out most is that,
in many of these situations,
SM's life was in danger, yet
her behavior lacked any
sense of desperation or
urgency. Police reports
obtained from the local
police department further
corroborate SM's recollection
of these events and paint a
picture of an individual who
lives in a poverty-stricken
area replete with crime,
drugs, and danger. Of note,
SM has never been convicted
of any crime, but rather has
been the victim of numerous
crimes. Moreover, it is
evident that SM has great
difficulty detecting looming
threats in her environment
and learning to avoid
dangerous situations,
features of her behavior that
have in all likelihood
contributed to her high
incidence of life-threatening
encounters.
Take, for example, an anecdote
reported by the Associated Press:
A man jumped up from a
park bench, pressed a knife
to her throat and hissed, "I'm
going to cut you."
SM, who heard a church
choir practicing in the
distance, looked coolly at him
and replied, "If you're going
to kill me, you're going to
have to go through my God's
angels first."
The man suddenly let her go.
She didn't run home. She
walked.
"Her lack of fear may have
freaked the guy out,"
Feinstein said.
But it also got her into that
situation in the first place, he
noted. SM had willingly
approached the man when
he asked her to, even though
it was late at night and she
was alone, and even though
she thought he looked
"drugged out."
The authors note that SM's
response to what would normally
be considered fear-inducing
situations was not characterized
simply by a lack of
responsiveness, but rather a
heightened arousal and interest.
In other words, she practically
courted danger.
Just as she felt curiosity instead
of fear in the face of scary
situations, so her memories of
frightening experiences also
diverged from the norm: when
asked about her emotional
response to such past incidents,
she reported feeling angry, but
didn't show the enduring
distress, panic and aversions that
typically characterize survivors of
similar violence.
These findings give researchers
some hope that they can
someday figure out how to
stimulate the amygdala in
survivors of violence to help
prevent them from suffering
post-traumatic stress disorder
later on.
The researchers stress that SM's
condition is more a curse than a
blessing: "[SM's] behavior, time
and time again, leads her back to
the very situations she should be
avoiding, highlighting the
indispensable role that the
amygdala plays in promoting
survival by compelling the
organism away from danger.
Indeed, it appears that without
the amygdala, the evolutionary
value of fear is lost."
Courtesy: Time Magazine
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