[Paleopsych] World Science: Bees can recognize human faces, study finds

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Bees can recognize human faces, study finds 
http://www.world-science.net/exclusives/051209_beesfrm.htm

    March 30, 2005

    Honeybees may look pretty much all alike to us. But it seems we may not look 
all
    alike to them.
    A study has found that the bees can learn to recognize human faces in 
photos,
    and remember them for at least two days.
    The findings toss new uncertainty into a long-studied issue that some 
scientists
    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 
brain,
    the authors of the new research said.
    Many researchers traditionally believed the task required a large brain and 
a
    specialized area of that brain dedicated to processing face information. The 
bee
    finding casts doubt on that, said Adrian G. Dyer, the lead researcher in the
    study.
    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 
invertebrate
    has shown ability to recognize faces of other species. But not all bees were 
up
    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
    specifically.
    In any cases, some humans also can't recognize faces, Dyer noted; the 
condition
    is called prosopagnosia.
    In the bee study, reported in the Dec. 15 issue of the Journal of 
Experimental
    Biology, Dyer and two colleagues presented honeybees with photos of human 
faces
    drawn from a standard human psychology test. The photos had similar 
lighting,
    background colors and sizes and included only the face and neck to avoid 
having
    the insects make judgments based on the clothing. In some cases, the people 
in
    the picture themselves looked similar.
    The researchers tried to train the bees to realize that one photo had a drop 
of
    a sugary liquid next to it. Different photos came with a drop of bitter 
liquid
    instead.
    Many bees apparently failed to realize that that they should pay attention 
to
    the photos at all. But five bees learned to fly toward the photo 
horizontally in
    such a way that they could get a good look at it, Dyer reported. In fact, 
these
    bees tended to hover a few centimeters in front of the image for a while 
before
    deciding where to land.
    The bees learned to distinguish the correct face from the wrong one with 
better
    than 80 percent accuracy, even when the faces were similar, and regardless 
of
    where the photos were placed, the researchers found. Also, just like humans, 
the
    bees performed more poorly when the faces were flipped upside-down. "This is
    evidence that face recognition requires neither a specialised neuronal 
[brain]
    circuitry nor a fundamentally advanced nervous system," the researchers 
wrote,
    noting that the test they used was one for which even humans have some
    difficulty.
    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 
the
    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 
humans
    judged as being more different. This seemed to be so, they found, but the 
result
    didn't reach statistical significance.
    The bees probably don't understand what a human face is, Dyer said in an 
email.
    "To the bees the faces were spatial patterns (or strange looking flowers)," 
he
    added.
    Bees are famous for their pattern-recognition abilities, which scientists
    believe evolved in order to discriminate among flowers. As social insects, 
it's
    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 
they do
    it differently from the way we do it, Dyer and colleagues wrote. Studies 
suggest
    small children recognize faces by picking out specific features that are 
easy to
    recognize, whereas adults see the interrelationships among facial features. 
Bees
    seem to show aspects of both strategies depending on the study, the 
researchers
    added.
    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 
show
    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 
visual
    area specific for the recognition of faces," Dyer and colleagues wrote.
    That may be helpful to researchers who develop face-recognition technologies 
to
    be used for security at airports and other locations, Dyer noted. The United
    States is investing heavily in such systems, but they remain primitive. 
Already,
    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 
mechanisms
    by which this is achieved then perhaps there are insights to how to try 
novel
    recognition solutions."
    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 
its
    nestmates will remember and come after you. Bees may launch revenge attacks, 
but
    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 
around
    looking at faces."