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ZL2VAL > SETI 23.04.04 12:57l 153 Lines 7280 Bytes #999 (0) @ WW
BID : 0E0780ZL2VAL
Read: GUEST
Subj: Language of space
Path: DB0FHN<DB0FOR<DB0SIF<DB0EA<DB0RES<ON0AR<7M3TJZ<JK1ZRW<ZL2AB
Sent: 040423/1046Z @:ZL2AB.#46.NZL.OC #:39285 [New Plymouth] FBB7.00g
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : SETI@WW
Unlocking Language in Space and on Earth
By Diane Richards
SETI Institute
posted: 06:30 am ET
22 April 2004
When Dr. Laurance Doyle lectures to undergraduates, he tells them "math
is not in the chalk," it is a tool they can use to understand the
universe. Doyle finds math everywhere; in the signatures of radio waves
that might reveal communication technology on other worlds; the
distribution and orbits of planets circling distant stars; and in the
calls of marine mammals.
At first glance, studying an endangered species may seem off target for
the SETI Institute astronomer, whose special expertise is planet
detection. Doyle, however, has exceptionally varied research interests.
He has written extensively on circumstellar habitable zones (cosmic real
estate that is bio-friendly), is a scientific collaborator on the NASA
Kepler mission, and teaches a course on Native American history.
He also works with biologists Brenda McCowan and Sean Hauser, of the
University of California, Davis, studying non-human communication
systems to better understand the nature of language and intelligence,
which in turn has direct relevance to the search for extraterrestrial
intelligence (SETI). Quantitative tools for intelligence studies are and
few and far between, making the Drake Equation term Fi (fraction of
planets on which intelligence develops) one of the most elusive facets
of SETI research.
Doyle's team uses statistical tools from a field known as "information
theory" to measure the complexity of different species' communication
systems and thus learn how much information individual animals can
transfer between each other. This allows the scientists to draw
inferences about the intelligence of the communicating species, which in
turn gives Fi researchers a better understanding of intelligence as an
evolutionary adaptation.
Information theory may also teach us how to approach the analysis of a
signal from distant worlds should SETI astronomers make a confirmed
detection. And -- as a surprising "SETI spin-off" -- information theory
may also help protect one of the planet's best-loved marine mammals.
Doyle explains the connection. "I was watching a television show about
whales." It was the late 70s, and he was working at JPL, processing
image data from Voyager. "The researchers were having trouble picking
out individual signals from the animals. I wanted to help." Doyle knew
his signal processing experience with Voyager could be useful. "We were
using a Hough transform to pick out signals from the noise."
Realizing that this signal processing technique could be applied to the
marine mammal calls, he contacted the Hubbs Research Center at Marine
World and was connected with researcher Sheldon Fischer. The pair began
to identify individual signals using the JPL technique. Unfortunately,
the analysis required intensive computational power which, unlike today,
was not practical for all but the largest research budgets. The project
was ultimately dropped, but the experience sparked Doyle's interest.
He "sat on it for seven years" before joining the SETI Institute in
1987, where he first encountered the small network of researchers
interested in dolphin intelligence and SETI. "We all intuited that the
study of dolphins may have something to do with SETI," Doyle explains,
"but we didn't know how to tie it all in."
Eventually, the right combination of research expertise would coalesce
into a collaboration between Doyle, McCowan, and Hauser. In the late
1990s a paper appeared in the journal Science, describing a novel use of
information theory to analyze the "language" of DNA. An Institute
colleague made "an off-hand comment" on the paper over lunch with Doyle,
and the germ of an idea took root.
"I went home that night with preprints of Brenda's dolphin signal paper,
and did a Ziff plot." The Ziff plot is a tool within information theory
that shows the relationship between repetitive and novel units of
communication within a system. Language, Doyle explains, has a
characteristic Ziff slope of 45 degrees. So did the dolphin. The results
astounded the astronomer, who remembers, "First I had to have a cup of
tea to make sure I got the figures right, then I called Brenda!"
Over the next year, the group pursued this line of research. In 2000,
Doyle's group, which also included Institute colleagues Dr. Christopher
Chyba and Taylor Bucci, launched an expedition to Glacier Bay, Alaska.
The researchers lowered hydrophones from their kayaks and gathered
signals from the feeding whales. In the course of the studies, says
Doyle, "we heard a lot of shipping noise, and decided to look for it in
the data."
Before returning home, the team gave a talk in the Glacier Bay
community, and caught the interest of local scientists who offered to
share several years of recordings with the California researchers. This
bonanza included data gathered during feeding sessions free of shipping
noise, allowing the team to build a baseline against which they could
compare the "noisy" recordings.
The results showed quantitatively that the boat noise was impacting the
communication. The humpbacks were having to "shout" above the noise,
repeating and simplifying their calls to each other, much like humans
trying to converse above the din of a noisy party. "We detected an
information decrease of about 28 percent in the presence of boat noise,"
says Doyle.
In the limited visibility environment of the ocean, humpbacks rely upon
vocalization for their social behavior, which includes feeding. Shipping
traffic was disrupting their communication, and by inference, their
social activities. The researchers will soon be collaborating with the
Alaskan Whale Foundation to gather more data, and coordinate the
communication studies with other research on the humpbacks, such as
studies of their physical health.
The future offers compelling research opportunities -- and challenges.
"There is plenty of work that needs to be done," says Doyle. Asked about
next steps, he explains, "We'd like to set up an array of hydrophones so
that we can triangulate individuals." Identifying individual whales by
their signals is highly sought goal of many marine mammal researchers.
Doyle smiles as he contemplates the road ahead. The research team would
like to build upon their work with whales and dolphins to include many
species in a survey of non-human communication systems. "We know how to
do it," he says earnestly. "All we need is the funding."
For now, Doyle's colleague Hauser looks forward to another season in
Alaska with the Whale Foundation. The more data the group has to
analyze, the more they can learn about the communication system, the
behavior, and the effects of the environmental context in which the
humpbacks socialize.
"It's a start," says Doyle. And a wonderful way to think about the
utility of math as we celebrate Earth Day.
=========================
73 de Alan, (Sysop ZL2AB).
AX25:ZL2VAL@ZL2AB.#46.NZL.OC
IP :zl2val@qsl.net
APRS:!3903.34S/17406.45E]
Message timed: 22:37 on 2004-Apr-23 (NZT)
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Points to ponder
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Rural wisdom
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A bumblebee is faster than a John Deere tractor.
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