Recognizing
Others’ Pheromones, Scents
Talking
Through Armpits
By Malcolm
Ritter
The Associated Press
N E
W Y O R K, March 11
Here's news to wrinkle your nose: In a study using armpit secretions,
scientists have found what they call the first proof that people can
influence each other through airborne chemical signals they don't even
notice.
When researchers wiped the secretions from one
group of women under the noses of other women, the second group showed
changes in their menstrual cycles. The cycles got either longer or
shorter, depending on where the donors were in their own menstrual
cycles.
The affected women said they didn't smell
anything but alcohol put on the pads. The alcohol alone had no effect on
the women's menstrual cycles.
Nobody has identified the underarm substances
that produced the effect, but once that happens, they might lead to new
contraceptives and infertility treatments, said Martha K. McClintock of
the University of Chicago, who reported the findings with a colleague in
Thursday's issue of the journal Nature.
The work adds to indications that people, like
animals from insects to elephants, influence each other by giving off
chemical signals called pheromones (pronounced FAIR-o-mones). In
animals, pheromones do such things as block pregnancies and influence
mating preferences, timing of puberty and dominance.
Common
Scents, But Pheromones?
The range of effects in people is still an open question. It's known
that newborns and their mothers can recognize each other's body odor,
for example, but scientists disagree on whether that counts as a
pheromone signal.
In any case, McClintock's paper "will
stand up as a classic in the field," said George Preti, a
researcher at the Monell Chemical Senses Center in Philadelphia who has
done similar research.
While some experts cautioned that the results
should be considered tentative until they are confirmed, others called
the findings convincing.
"The work is pivotal," said Charles
Wysocki of Monell. "It basically says, `Look, people, we are
influenced by pheromones that emanate from other people."'
Aron Weller, a psychologist of Bar-Ilan
University in Ramat-Gan, Israel, who wrote a Nature commentary on
the paper, said in an interview that the study is "the most
convincing and clear-cut finding of human pheromones."
But he said it's not clear yet whether these
pheromones have any effect in everyday life. Past studies—including
some by McClintock and Weller—have shown that the cycles of women who
live together can synchronize, especially between close friends.
Pheromones probably cause that, but the link isn't yet proven, Weller
said.
Pheromones
Affect Ovulation
McClintock's study found that the secretions affected the timing of
ovulation, which is the production of mature eggs. Once scientists
identify the compounds responsible and the details of how they work,
they might be able to create new compounds that suppress or encourage
ovulation, McClintock said. Such compounds might be useful as
contraceptives or treatments for some cases of infertility, she said.
Her experiment involved nine donor women and 20
recipient women in their 20s and 30s. The donors bathed without perfumed
products every day and then wore cotton pads in their armpits for at
least eight hours.
Later, pieces of these pads were wiped under
the noses of the recipient women every day for four consecutive
menstrual cycles. The women weren't told what the researchers were
studying.
For two cycles, each recipient got secretions
produced late in the follicular phase of the donors' menstrual cycle,
which precedes ovulation. For the other two cycles, each recipient was
given secretions produced at the time of ovulation.
The recipients' cycles were shorter than normal
when they were exposed to follicular-phase secretions, and longer than
normal when they got ovulatory secretions. Each effect amounted to about
1.5 days' difference from the norm on average, but ranged up to 14 days,
and appeared in about two-thirds of the women.
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