[Paleopsych] World Science: Bees can recognize human faces, study finds
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Bees can recognize human faces, study finds
March 30, 2005
Honeybees may look pretty much all alike to us. But it seems we may not look
alike to them.
A study has found that the bees can learn to recognize human faces in
and remember them for at least two days.
The findings toss new uncertainty into a long-studied issue that some
considered largely settled, the researchers say: the question of how humans
themselves recognize each other's faces. The results also may help lead to
better face-recognition software, developed through study of the insect
the authors of the new research said.
Many researchers traditionally believed the task required a large brain and
specialized area of that brain dedicated to processing face information. The
finding casts doubt on that, said Adrian G. Dyer, the lead researcher in the
He recalls that the discovery startled him so much that he called out to a
colleague, telling her to come quickly because "no one's going to believe
it--and bring a camera!"
Dyer said that to his knowledge, the finding is the first time an
has shown ability to recognize faces of other species. But not all bees were
to the task: some flunked it, he said, although this seemed due more to a
failure to grasp how the test worked than to poor facial recognition
In any cases, some humans also can't recognize faces, Dyer noted; the
is called prosopagnosia.
In the bee study, reported in the Dec. 15 issue of the Journal of
Biology, Dyer and two colleagues presented honeybees with photos of human
drawn from a standard human psychology test. The photos had similar
background colors and sizes and included only the face and neck to avoid
the insects make judgments based on the clothing. In some cases, the people
the picture themselves looked similar.
The researchers tried to train the bees to realize that one photo had a drop
a sugary liquid next to it. Different photos came with a drop of bitter
Many bees apparently failed to realize that that they should pay attention
the photos at all. But five bees learned to fly toward the photo
such a way that they could get a good look at it, Dyer reported. In fact,
bees tended to hover a few centimeters in front of the image for a while
deciding where to land.
The bees learned to distinguish the correct face from the wrong one with
than 80 percent accuracy, even when the faces were similar, and regardless
where the photos were placed, the researchers found. Also, just like humans,
bees performed more poorly when the faces were flipped upside-down. "This is
evidence that face recognition requires neither a specialised neuronal
circuitry nor a fundamentally advanced nervous system," the researchers
noting that the test they used was one for which even humans have some
Also, "Two bees tested 2 days after the initial training retained the
information in long-term memory," they wrote. One scored about 94 percent on
first day and 79 percent two days later; the second bee's score dropped from
about 87 to 76 percent during the same time frame.
The researchers also checked whether bees performed better for faces that
judged as being more different. This seemed to be so, they found, but the
didn't reach statistical significance.
The bees probably don't understand what a human face is, Dyer said in an
"To the bees the faces were spatial patterns (or strange looking flowers),"
Bees are famous for their pattern-recognition abilities, which scientists
believe evolved in order to discriminate among flowers. As social insects,
well known that they can also tell apart their hivemates. But the new study
shows that they can recognize human faces better than some humans can--with
one-thousandth of the brain cells.
This raises the question of how bees recognize faces, and if so, whether
it differently from the way we do it, Dyer and colleagues wrote. Studies
small children recognize faces by picking out specific features that are
recognize, whereas adults see the interrelationships among facial features.
seem to show aspects of both strategies depending on the study, the
The findings cast doubt on the belief among some researchers that the human
brain has a specialized area for face recognition, Dyer and colleagues said.
Neuroscientists point to an area called the fusiform gyrus, which tends to
increased activity during face-viewing, as serving this purpose. But the bee
finding "supports the view that the human brain may not need to have a
area specific for the recognition of faces," Dyer and colleagues wrote.
That may be helpful to researchers who develop face-recognition technologies
be used for security at airports and other locations, Dyer noted. The United
States is investing heavily in such systems, but they remain primitive.
the way that bees navigate is "being used to design self-autonomous aircraft
that can fly in remote areas without the need for radio contact or satellite
navigation," he wrote in the email. "We show that the miniature brain can
definitely recognize faces, and if in the future we can work out the
by which this is achieved then perhaps there are insights to how to try
On the other hand, Dyer said, the findings probably don't back up an adage
popular in some parts of the world--that you shouldn't kill a bee because
nestmates will remember and come after you. Bees may launch revenge attacks,
they might simply do so because they smell the dead bee, he remarked, adding
that that's his speculation only. In any case, "bees don't normally go
looking at faces."
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