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The ants are tiny and usually nest between rocks in the south coast
of England. Transformed into research subjects at the University of
Bristol, they raced along a tabletop foraging for food -and then,
remarkably, returned to guide others. Time and again, followers trailed
behind leaders, darting this way and that along the route, presumably to
memorize land- marks. Once a follower got its bearings, it tapped the
leader with its antennae, prompting the lesson to literally proceed to the
next step. The ants were only looking for food but the researchers said the
careful way the leaders led followers -thereby turning them into leaders in
their own right -marked the Temnothorax albipennis ant as the very
first example of a non-human animal exhibiting teaching behavior.
"Tandem running is an example of teaching, to our knowledge the
first in a non-human animal, that involves bidirectional feedback between
teacher and pupil," remarks Nigel Franks, professor of animal behavior
and ecology, whose paper on the ant educators was published last week in
the journal Nature.
No sooner was the paper published, of course, than another educator
questioned it. Marc Hauser, a psychologist and biologist and one of the
scientists who came up with the definition of teaching, said it was unclear
whether the ants had learned a new skill or merely acquired new
information.
Later, Franks took a further study and found that there were even
races between leaders. With the guidance of leaders, ants could find food
faster. But the help comes at a cost for the leader, who normally would
have reached the food about four times faster if not hampered by a
follower. This means the hypothesis that the leaders deliberately slowed
down in order to pass the skills on to the followers seems potentially
valid. His ideas were advocated by the students who carried out the video
project with him.
Opposing views still arose, however. Hauser noted that mere
communication of information is commonplace in the animal world. Consider a
species, for example, that uses alarm calls to warn fellow members about
the presence of a predator. Sounding the alarm can be costly, because the
animal may draw the attention of the predator to itself. But it allows
others to flee to safety. “Would you call this teaching?” wrote Hauser.
“The caller incurs a cost. The naive animals gain a benefit and new
knowledge that better enables them to learn about the predator’s location
than if the caller had not called. This happens throughout the animal
kingdom, but we don’t call it teaching, even though it is clearly transfer
of information.”
Tim Caro, a zoologist, presented two cases of animal communication.
He found that cheetah mothers that take their cubs along on hunts gradually
allow their cubs to do more of the hunting -going, for example, from killing
a gazelle and allowing young cubs to eat to merely tripping the gazelle and
letting the cubs finish it off. At one level, such behavior might be called
teaching -except the mother was not really teaching the cubs to hunt but
merely facilitating various stages of learning. In another instance, birds
watching other birds using a stick to locate food such as insects and so
on, are observed to do the same thing themselves while finding food later.
Psychologists study animal behavior in part to understand the
evolutionary roots of human behavior, Hauser said. The challenge in
understanding whether other animals truly teach one another, he added, is
that human teaching involves a “theory of mind” -teachers are aware that
students don’t know something. He questioned whether Franks’s leader ants
really knew that the follower ants were ignorant. Could they simply have
been following an instinctive rule to proceed when the followers tapped
them on the legs or abdomen? And did leaders that led the way to food -only
to find that it had been removed by the experimenter -incur the wrath of
followers? That, Hauser said, would suggest that the follower ant actually
knew the leader was more knowledgeable and not merely following an
instinctive routine itself.
The controversy went on, and for a good reason. The occurrence of
teaching in ants, if proven to be true, indicates that teaching can evolve
in animals with tiny brains. It is probably the value of information in
social animals that determines when teaching will evolve rather than the
constraints of brain size.
Bennett Galef Jr., a psychologist who studies animal behavior and
social learning at McMaster University in Canada, maintained that ants were
unlikely to have a “theory of mind” -meaning that leader and followers may
well have been following instinctive routines that were not based on an
understanding of what was happening in another ant’s brain. He warned that
scientists may be barking up the wrong tree when they look not only for
examples of humanlike behavior among other animals but humanlike thinking
that underlies such behavior. Animals may behave in ways similar to humans
without a similar cognitive system, he said, so the behavior is not
necessarily a good guide into how humans came to think the way they do.
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