Magazine - summer 03 - St. John's College

{Alumni Profile}
31
This painstaking research was what Chaski
went back to when a homicide detective
named W. Allison Blackman brought her a
computer disk with suicide notes allegedly
written by Michael Hunter, a young man
found dead of a lethal combination of drugs
injected into his arm. Blackman didn’t have
much to go on when he came to Chaski and
asked if she could examine the note and
other writing samples from Hunter to determine
if he had really written the suicide note.
“I know how to analyze syntax and I know
how to find patterns,” she told Blackman.
“I’ll try it and we’ll see.”
Chaski looked at writing samples for
Hunter and his two roommates, including a
young medical student named Joseph Mannino,
who had easy access to the drugs in
Hunter’s system. Chaski found that patterns
in the suicide note—particularly the use of
conjunctions—were strikingly similar to
those of Mannino, who was involved in a
three-way affair with Hunter and a third
roommate. The suicide notes were marked by
conjunctions between sentences. Samples of
Hunter’s authentic writing included more
conjunctions between non-sentence phrases.
Police eventually arrested Mannino. After
a three-week trial, he was convicted of involuntary
manslaughter and sentenced to seven
years in prison.
After consulting with the local district
attorney’s office on another case (identifying
the author of an anonymous threatening letter),
Chaski knew she had found something
more satisfying and more challenging than
an academic career. “At St. John’s, we talk a
lot about the examined life. I just wasn’t
happy as an academic. It seemed that the primary
role of professors was to get away from
the students,” she says.
She secured a fellowship at the National
Institute of Justice (the research arm of the
U.S. Justice Department) and set about finetuning
a method to distinguish one author
from another based on syntactic patterns. “I
was the only one doing any research independent
of litigation,” Chaski says.
As part of her research, Chaski set about
examining every method already employed
in language identification. She demonstrated
that analyzing language based on the
spelling, punctuation, and grammatical
errors was not good enough to determine
individuality in writing. “I’m really against
the prescriptive, stylistics method because
what pops out to people as odd is not a pattern,
it’s just what’s popping out,” she
explains. “It’s like Plato’s cave—you can’t
know the light until you know the shadow,
and you have to have them both. In DNA
analysis, if you’re looking for a chromosomal
anomaly, you have to have the whole
pattern. That’s where you start in syntactic
analysis. Every document is analyzed for
every syntactic pattern and nothing is left
out. That way you can find out if something
that seems unusual in a piece of writing
really is unusual.”
Similarly, the type of analysis scholars
undertake in trying to determine the authorship
of something like a Shakespeare play or
a Biblical text (content analysis, vocabulary
“It’s like Plato’s cave—
you can’t know the light
until you know the
shadow, and you have
to have them both.”
Carole Chaski, A77
richness, the complexity of sentences) is not
suited to forensic linguistics, where documents
conveying death threats or ransom
demands are usually short and to the point.
Chaski has spent the last decade or so
refining and applying a scientific method for
syntactic analysis that is rooted in linguistic
theory and validated by statistical testing.
Each analysis begins with taking texts apart
and labeling each word for its part of speech,
then taking phrases within the sentences and
parsing those. “Once the phrases are all
determined, I categorize them into two
types: marked and unmarked. Unmarked are
phases that are so common, they don’t stand
out—‘it’s in the car.’ Marked are those that
are more infrequent or more remarkable—
‘it’s in the car, in the garage, attached to
the house.’’’
Next, Chaski determines the frequency of
marked and unmarked phrases in the writing
samples. Those numbers are fed into computer
programs that yield three different
statistical analyses. The first two methods,
discriminate function analysis and logistic
regression, seek a clear division between the
questioned document and the other known
writing samples in her pool. The third test,
hierarchical cluster analysis, seeks similarities
by “clustering” similar samples into the
same pool.
“Everybody starts out in a pool of potential
authors. If the statistical procedures
show there’s a significant difference, people
are excluded. If I can’t find any difference
between a suspect’s writing sample and the
evidence document, that’s what my report
will say,” Chaski says, adding, “I never claim
that only one person in the world could have
written something.”
Several years ago, Chaski left Washington
for Georgetown, Del., where she founded the
Institute for Linguistic Evidence, of which
she is executive director. Along with continuing
research, lecturing, and writing about
her methods, Chaski has served as a consultant
in a number of intriguing cases where her
research influenced the outcomes. In one
Annapolis case, the founder of a firm that
developed environmental technology was
sued by a former employee who wanted a
significant share of the profits reaped from
the company’s product. However, the company’s
owner suspected the man had written
damaging letters to potential customers.
“The lawyers for the defendant came to
me and they were already convinced that it
was this engineer. In this case, the pool was
limited to those who worked for the company—only
they had the technical knowledge to
write the letters, ” Chaski explains. Her
analysis proved the defendant correct, and
on that basis, the judge overruled the jury
verdict to give the fired engineer the small
sum the jury had agreed upon.
In another recent civil case, Chaski
determined that a woman claiming sexual
harassment in her workplace was the
author of e-mails that indicated the relationship
between her and her supervisor
was consensual. Chaski also showed that a
federal employee who was fired for writing
racist e-mails was very probably the author
of those missives. In other cases, Chaski’s
work has taken her into state and federal
courts, where her testimony has passed
successfully through the scrutiny of
evidence hearings.
Chaski believes it’s possible for someone
to succeed in imitating another’s writing to
a degree, but that it’s impossible to suppress
one’s own style completely. “Language
is meant to be meaning-centered, not
syntax-centered. Syntax is fundamental, it’s
what makes language efficient. But it’s very
abstract, very automated. If we thought
about it, we’d go nuts—‘how many prepositional
phrases did I just write?’—and not
actually be able to communicate.”
Given her St. John’s education, it’s not
really odd that Chaski was drawn to forensic
linguistics. “That’s because Johnnies learn to
think about, and talk about, language as language,”
says Chaski. x
{ The College • St. John’s College • Fall 2004 }