"THAT DAMN BIRD"
For the past 26 years I've been studying the
cognitive and communicative abilities of
Grey parrots. My oldest bird, Alex, can
identify about 50 different objects using
English labels. He can also label seven
colors, five shapes, and quantities up to
and including six. He has functional use of
phrases like "I want X" and "I wanna go Y",
where X and Y, respectively, are object or
location labels. He combines these labels to
identify, refuse, request and categorize
more than a hundred different items. He has
concepts of bigger and smaller, of category,
of sameness and difference, of absence of
information, and of number.
We test him not only through direct
questions about these concepts (e.g., "What
color bigger?" for two differently sized and
colored blocks), but also by using questions
that involve complex structures—recursive
phrases or conjunctive, recursive
phrases—such as, "What object is green and
three-corner?"; he answers all these
questions with about 80% accuracy. We think
the reason he doesn't achieve 100% accuracy
is boredom; he seems to get tired of
repeatedly telling us about colors and
shapes and materials. For example, he
sometimes will state every color but the
correct one, behavior that suggests that he
is carefully avoiding the right answer;
statistically, he couldn't do that by
chance.
He
also understands categories in terms of
hierarchical levels, so he knows that
there's this weird (to him) sound called
"color" and under that weird sound are
grouped all these other sounds called "red,"
"blue," "green," "yellow," "orange," etc.
that relate to a specific set of physical
attributes of objects. Similarly, he
understands there is another weird sound,
"shape," and under that sound there are the
other sound patterns "two-", "three-",
"four-", "five-", and "six-corner" that
relate to different physical attributes of
the same objects. We can teach him new ways
of categorizing items. If he's already
learned to categorize items by color and
shape, we can then ask him to categorize
them by number. Furthermore, Alex
demonstrates a certain level of
intentionality involving requests. If he
says that he wants grape and you give him a
banana, you are going to end up wearing the
banana.
Over the course of the last 26 years or so
we've also pursued studies with other birds
on a variety of different topics, some of
which demonstrate very interesting parallels
between vocal communication in birds and
humans.
We've fairly recently completed a wonderful
study with the middle bird, Griffin, based
on some work by Patricia Greenfield, and I
have to provide a bit of background for the
importance of the study to be appreciated.
In the 1970s, Greenfield looked at young
children and found that at the time they
start serially and hierarchically stacking
toys like cups and rings in perfect order,
they also start combining their labels in
somewhat regular syntactic patterns; that
is, they begin to produce phrases like "Want
cookie," or "Want more milk." Greenfield
initially argued that this synergy is a
uniquely human trait and that it heralds the
emergence of human language. She later
argued that both these behavior patterns
were initially controlled by one particular
part of the brain, Broca's area, and that as
a child matured, the area simply separated
into sections for physical and linguistic
combinatory behavior.
At this time, she also was looking at data
from chimpanzees that were using sign
language and computers to communicate with
humans, and found that, lo and behold, just
when the chimps started to stack their cups
and rings hierarchically, they also started
putting together their symbols to form
phrases like "Want more banana." Greenfield
thus decided these behavior patterns were
unique to primates and were involved in the
evolution of language. She furthermore
argued that the ape had a homologous, if
more rudimentary, Broca-like system that
allowed it to perform the same types of
early combinatory behavior as did children.
In hindsight what is fascinating about this
material is that Greenfield's proposal was
published about four years before the first
papers on mirror neurons appeared. If you
know anything about mirror neurons, you
realize the connection.
Mirror neurons are those bits of the brain
that respond to an action the same way
whether you see the action being performed
or if you do the action yourself. This
response occurs for both gestural actions
(those done physically, with one's hands),
and those done orally (with one's mouth).
And many of these neurons are in Broca's
area. Thus data exist that can be
interpreted to support the gestural origin
of language; that is, that a small change in
one part of the brain could have led to the
change from learning communicative gesture
to learning speech through an imitative
program, and that the same area could indeed
initially be used for both simple gestural
and linguistic combinations.
In the 1990s, Greenfield and her colleagues
began studying the same types of tasks with
monkeys (who, by the way, can't imitate),
seeing how far through the primate line
these abilities extended. They found that
monkeys can be trained, slowly and
painfully, to do serial hierarchical
stacking, and that examination of their
natural vocalizations uncovered some limited
combinatorial ability — maybe one or two
calls that they will put together. Thus
monkey combinatory ability exists, but is
not very well-developed.
Greenfield and her colleagues proposed a
split within the primate lineage: between
the monkeys that don't have spontaneous
complex combinatory communication or complex
physical combinatorial skills, and the
chimps and humans, who do—with the human
abilities far outstripping those of the
apes. Greenfield didn't study orangutans or
gorillas, but these apes (given studies on
their use of American Sign Language) are
probably at the same level as the
chimpanzees. Thus, researchers had data
supporting the uniquely primate origins of
language — a beautiful story.
"Except," as my friend and colleague Mike
Tomasello would say, "for that damn bird."
Mike and I joke a lot about this phrase,
because many times when he presents his data
he says that the described behavior is found
only in primates — except for "that damn
bird," referring to the abilities that my
Grey parrot, Alex, has demonstrated. It was
not Alex this time, however, but Griffin.
One of my students was cleaning up the
laboratory and we recycle whatever we can,
so she was collecting all the empty bottles,
throwing them in a bin, and separating out
all the caps and putting them on the counter
where Griffin was sitting. She calls me over
and says, "You told me that parrots are
destructive foragers and that they don't
really put things together, so come here and
take a look." And there was Griffin, taking
smaller caps and putting them into bigger
caps, and picking up the pairs and throwing
them off the side of the counter. This
incident occurred at about the same time
that he was saying things like "want
walnut," and "green grape," and other
combinations of that nature.
|
Griffin |
We took a deep breath and said, "Okay, we
have a nice anecdote but we have to look at
the behavior scientifically." So we started
examining three-level combinations. We began
by giving Griffin lots of different bottle
caps and jar lids and things that he could
put together, and by training him on a very
small number of three label combinations —
two-corner wood, two-corner paper,
five-corner wood, five-corner paper — to
give him the idea that he had to combine his
labels.
There's no reason for the parrots to make
three-label combinations spontaneously; we
must train them, because we're teaching them
our language rather than trying to
understand theirs. Interestingly, he did a
single three-level combination with the caps
early on, and then stopped. Too, training on
three-label combinations took an inordinate
amount of time. Usually when we train him on
vocal labels, he starts making some attempt
after about 20 sessions. That's at most ten
weeks. Usually it's much less than that, but
10 weeks is the worst-case scenario unless
other issues are involved.
We started the experiment around June, and
months went by and he wasn't putting
together more than two bottle caps or lids
and wasn't saying any three-label
combinations, but we kept working.
In February, within the space of ten days,
he started making three object combinations
and started putting three labels together.
Ten days! It was as though something in his
brain had had to mature or some wiring had
to develop. Interestingly, over the course
of the experiment, the percentage of
three-label combinations and the percentage
of three-item combinations were the same:
about six to ten percent. He wasn't very
proficient at any of the triple combinations
but he was forming them. He continued
primarily to utter two-label combinations
and construct two-object combinations; he
succeeded on something like 200 of 210
two-object attempts, performing easily and
correctly. The fascinating point, in
addition, was that of all of his vocal
three-label combinations, he used only one
on which he had been trained. The rest of
his three-label utterances were ones he put
together himself, like "want green nut" or
"wanna go chair" or "you wanna go chair." He
used 14 representative three-label
combinations and repeated each of those many
times.
Now, parrots don't have a Broca's area. They
may have something like a Broca's area, but
Griffin's data demonstrate that simultaneous
emergence of physical and vocal combinatory
behavior is clearly not unique to primate
brains, nor to human language. We have to go
back to dinosaurs if we're looking for
something homologous in terms of brain
evolution. Even if we believe that we are
seeing convergent evolution, convergent
evolution still requires a basis on which to
build.
What the data suggest to me is that if one
starts with a brain of a certain complexity
and gives it enough social and ecological
support, that brain will develop at least
the building blocks of a complex
communication system. Of course, chimpanzees
don't proceed to develop full-blown language
the way you and I have. Grey parrots, such
as Alex and Griffin, are never going to sit
here and give an interview the way you and I
are conducting an interview and having a
chat. But they are going to produce
meaningful, complex communicative
combinations. It is incredibly fascinating
to have creatures so evolutionarily separate
from humans performing simple forms of the
same types of complex cognitive tasks as do
young children.
Why is this material important as well as
fascinating? Because it suggests that to
understand the evolutionary bases for
cognition, we must also examine cognition in
creatures quite removed from humans. Other
forms of cognition exist that are as
interesting, as important, and that might
have similar evolutionary bases.
Parrots live in an environment that both
matches and differs from that of apes. With
respect to similarities, birds also have to
deal with a complex ecology. Grey parrots,
for example, forage up to 60 kilometers a
day. They are at least as long-lived as
apes, so they must keep track of changes in
the rain forest and the savanna over the
course of 30 to 60 years — both seasonal
changes and long-term environmental changes.
Greys live in large flocks. Unlike apes,
they separate out into pairs during breeding
seasons. We don't know too much about their
social strata, but they definitely defend
their nest areas from other pairs. We
suspect, given what we see in the laboratory
— and this is not a joke — a definite
pecking order and hierarchy, at least in
small groups.
We know that chimpanzees and monkeys must
keep track of social strata by what in
humans would be termed "transitive
inference" — that if Sam beat up on Joe and
Joe beat up on me, I'd better not even go
near Sam. This information is important for
survival in a group. But such information
also is not static; it has to be upgraded
over the course of the animals' lives.
Possibly parrots have similar strata. Nick
Humphrey suggested these ideas almost 30
years ago; that is, given a long-lived
creature that exists in a complex
socio-ecological system, that creature has
likely been selected for high-level
intelligence and cognition. I think those
same evolutionary pressures work on parrots.
My interest in parrots developed in a
somewhat unusual way. My doctorate is
actually in theoretical chemistry from
Harvard, but I was not a very happy chemist.
I was good at it, but not very satisfied.
While working on my doctorate, I saw several
NOVA programs — that was the first year of
NOVA — programs on the signing chimps, on
singing whales, on communicative studies
with dolphins, and the critical one, "Why do
Birds Sing?" Researchers presented data on
the complex communication of songbirds, and
how it was somewhat learned.
And there was a striking interview with
Peter Marler, who, as a botanist/chemist
graduate student, noticed the different
chaffinch dialects in the various areas in
which he was collecting biological samples,
and who described how he switched from
chemistry to birdsong. It was an epiphany
for me: First, the realization that one
could switch from chemistry to studying
birds; second, that nobody was studying
birds the same way that primates were being
studied. I had had parakeets as a child, and
my pets always talked. So, here was a
creature that could actually talk to you,
and that seemed rather intelligent, and no
one was trying to teach it to communicate
with humans using meaningful speech. That's
when I decided to pursue this topic.
By the way, I did finish the doctorate. I
spent 40 hours a week finishing the
doctorate, and another 40 hours a week
reading in the libraries at Harvard and
sitting in on courses, training myself in
biology, in child language, in psychology, a
little bit of anthropology — all the topics
one would need to pursue studies in
animal-human communication.
My work was not initially thought possible.
When I first wanted to begin this research,
I submitted a grant proposal to NIH, and the
panel came back with reviews essentially
asking me what I was smoking, because nobody
thought birds could do anything remotely
like what I was proposing.
So I worked with undergraduate volunteers,
with my friends' high-school children,
showed that parrots could referentially
label objects, and resubmitted the grant to
NSF. I got a very small amount of funding,
and came up for renewal. Then the reviewers
said, "That's fine, but do parrots
understand categorization?" So my students
and I showed that Alex could label an object
by its color, its shape, and its material;
we demonstrated an understanding of
hierarchical categories that I described
earlier. Nobody thought birds could do that.
Then my critics said, "That's all well and
good, but parrots don't have concepts of
'same' and 'different' the way Premack's
chimps do."
So we made Alex do this task "backwards and
in heels": Premack's chimps had only to
designate whether two objects were the same
or different; Alex had to look at two items
and tell you the label of the category that
was the same or different, that is, with
respect to color, shape, or material (e.g.,
we'd give him two wooden squares of
different colors, and ask "What's
different?", or a yellow paper triangle and
a blue wooden one and ask "What's same?").
Then we started looking at concepts of
absence, because people said that animals
don't have such a concept. I argued that of
course they have to respond to absence of
information in the wild: They understand
that "if my neighbor bird is not singing, it
is probably gone and I can invade its
territory." So we demonstrated that Alex
could respond "none" if nothing was same or
different about two items.
The same issues arose with concepts of
number. Lenneberg wrote papers in the late
1960s to early 1970s basically saying that
animals don't have a number sense because
they don't understand abstract
representations and relational concepts. We
therefore did a series of studies on number,
showing that Alex could, for example, look
at a tray of intermingled red and blue balls
and blocks and tell us how many blue blocks
were on the tray (that is, ignore the red
and blue balls and the red blocks, and focus
on one subset of items); a four-year-old
child has problems with such a task. And so
it continues. Every time that people said
that parrots can't do something, I've been
able to show that they have some ability
with respect to the concept in question, and
in some cases I've been able to show more
complex understanding than other researchers
have been able to show in the primates.
A
lot of people are interested in the work I'm
doing. Certainly the primatologists and
psychologists are interested, because of the
comparative issue. Anthropologists, for the
same reason. Ornithologists are becoming
more interested as they realize how much
intelligence birds need to survive in their
ecological niches. Medical researchers are
interested, because it turns out that the
training techniques we use for the birds
tend to work extremely well for autistic
children. I work with a clinician in
Monterey, California named Diane Sherman.
She has a private practice, and has a Grey
parrot — that's how we met — and she's taken
these techniques we use for training our
parrots and adapted them with incredible
success for use with children who have
various social and communicative
disabilities. How successful the techniques
are depends to some extent on where the
child starts — she can't take a child with
almost no skills and bring it up to a level
that's normal for its age — but every child
she's worked with, using our procedures, has
made significant gains.
My research is also really important for the
pet industry. What I've tried to explain to
parrot owners is that what they have in a
cage in their living room is a creature with
the sentience of a four- to six-year-old
child. I try to convince them that you can't
just lock it in a cage for eight hours a day
without any kind of interaction. I don't
mean just interpersonal interaction, or
having other birds around; parrots have to
be intellectually challenged. In the wild
they are constantly challenged. They are
challenged to find food, they are challenged
to avoid predators, and they are challenged
by the intra-flock interactions.
In contrast, what does a pet do? The bird
sits alone in a cage all day, with ample
food and water in nice accessible cups, and
vegetates. Some birds in such situations
pluck their feathers; they scream, they bite
— they act in ways similar to those of a
4-year-old having a temper tantrum because
it had been left it alone in a playpen for
eight hours with maybe one toy and some
snacks. I've tried to help these people
understand what they are getting themselves
into, and hopefully have convinced them to
enrich the lives of these birds as much as
possible.
One of the other things to remember when you
have a pet parrot is that this bird is a
flock creature. One parrot in the wild is a
dead parrot. It can't forage and look for
predators at the same time. So when you have
one bird in your house, or even two birds of
separate species, you have a bird that is
seeking companions as well as stimulation.
One of the things we were trying to do when
I was at the Media Lab was to devise
different types of computer-based enrichment
programs for these birds. We created
something called "InterPet Explorer," which
was a modified Web browser for the bird. We
hadn't developed it fully, but the bird had
four choices of input. It could see video,
listen to music, see pictures, or play a
game that we were designing. Within each of
those categories were four choices. Under
the music selection, for example, the bird
could initially choose from clips of rock,
country, classical or jazz. Alex would play
with this system for about an hour in the
morning before we came into the lab.
At first he was interacting with it a lot,
and then seemed to lose interest; the
students were concerned that the system was
a failure. I asked them, "Well, how often
are you changing content?" The students
looked at me as though I was insane and
replied, "What do you mean?" And I said,
"How often do you want to hear Vivaldi's
Cello Concerto?" They then reorganized the
system to use four different channels of
Internet radio so that Alex had something
different whenever he clicked a choice, and
Alex's interest shot back up.
Ben Resner and Bruce Blumberg created
"Rover@Home," in which you could play with
your dog over the Internet while you were at
work. These are examples of the kinds of
interactive systems we were trying to
develop, so you could sit at your desk
during your coffee break and use cameras and
computers to connect with your animals. I
hoped it would be the start of a serious
research program, not just for pets, but
also to enrich the lives of various species
in zoos and even research subjects in animal
care facilities. For a lot of reasons, it
didn't happen. The idea is still out there,
though, and I think somebody is going to
pick it up one of these days and run with
it.
There are many studies my students and I
still want to do with our parrots. For
example, we want to look at spatial
concepts. For people, "over" and "under" are
pretty standard concepts. We know what's
over us and under us, and, yes, we can crawl
under a table and change our perspective,
but that's a special case. Parrots, in
contrast, are much more three-dimensional.
As they fly, within a second what is over
them is under and vice versa. Could a parrot
understand the concept of over and under
separate from the relationship to its own
body? So, for example, if it learned to tell
you that the key is above the cork with
respect to the midline of its head, what
would happen if you then moved both objects
above its head? Could it still understand
"over" and "under" for two items when they
are not correlated to its own body as the
frame of reference?
We also want to pursue number work further.
At present, Alex can identify quantities up
to six, but is it real counting? Would he
succeed on a Piagetian style task in which
you give him two lines of objects — with the
same numbers of items — but then you crunch
one together, to make it shorter. If you ask
children, at one point they come to
understand that the numbers are the same in
the two lines, but earlier in development
they confuse length with number; how will
parrots respond?
We are going to do some more studies with
recursion. Hauser, Chomsky and Fitch
published a paper in Science at the end of
October 2002 stating that only humans
produce recursive phrases and that recursion
is thus what separates human language from
animal communication systems. Well, parrots,
dolphins and sea lions respond to recursive
sentences. Dolphins and sea lions will
differentially respond to statements such as
"Touch the surfboard that is grey and to the
left" versus "Swim over the Frisbee that is
black and to your right." Alex responds to
questions such as "What object is green and
three-corner?" versus "What color is wood
and four-corner?" or "What shape is paper
and purple?"
Hauser et al. claim that the animals'
responses involve comprehension rather than
production, and therefore don't count. But
comprehension is often used as evidence of
proof of concept, particularly in young
children who aren't yet verbal. Rather than
argue, we are trying to train Alex now to
produce long phrases in response to
questions like "Where's the key?" or
"Where's the nut?"; that is, have him tell
us "It's in the blue cup that's on the
tray," in contrast to "It's in the yellow
box on the chair." Those are some of the
types of tasks on which we are really eager
to start working.
Such research again touches on the
relationship of my work to that of people
who are looking into topics like
consciousness and what defines human
language; that is, how does one reconcile
arguments for the uniqueness of humans with
evidence for lower-level building blocks of
these phenomena in other creatures?
Researchers such as Pinker and I get along
well because I never claim that Alex has
full-blown language; I never would. I'm not
going to be able to put Alex on a "T" stand
and have you interview him the way you
interview me. But Alex has basic building
blocks that are language-like behaviors —
and also elements of phenomena like
consciousness and awareness. Is Alex
conscious? Personally, I believe so. Can I
prove it? No. Does he have perceptual
awareness? That I can definitely prove.
We can give him Piagetian object permanence
tasks, where you hide things in various ways
under cups; Alex and Griffin show that they
know that the objects are still there,
meaning that they understand that "out of
sight" does not mean that the object ceases
to exist. We play the equivalent of shell
games with our birds (like games at
carnivals, where you hide an object under
one of three cups and then switch the cups
around), and both birds still find the
hidden item. We did one study in which the
procedure requires the experimenter to
deceive the subject. You make believe that
you're putting the object under one cup but
you sneak it under another other or replace
it with a less desirable item. So Alex goes
over to where he expects the item to be,
picks up the cup, and finds that the nut is
not there; he starts banging his beak on the
table and throwing the cups around. Such
behavior shows that Alex knew that the
object was supposed to be there, that it's
not, and he's giving very clear evidence
that he perceived something, and that his
awareness and his expectations were
violated. Griffin responds the same way.
There are some things that the birds do
that, colloquially speaking, "just blow us
away." We were training Alex to sound out
phonemes, not because we want him to read as
humans do, but we want to see if he
understands that his labels are made up of
sounds that can be combined in different
ways to make up new words; that is, to
demonstrate evidence for segmentation. He
babbles at dusk, producing strings like
"green, cheen, bean, keen", so we have some
evidence for this behavior, but we need more
solid data.
Thus we are trying to get him to sound out
refrigerator letters, the same way one would
train children on phonics. We were doing
demos at the Media Lab for our corporate
sponsors; we had a very small amount of time
scheduled and the visitors wanted to see
Alex work. So we put a number of differently
colored letters on the tray that we use, put
the tray in front of Alex, and asked, "Alex,
what sound is blue?" He answers, "Ssss." It
was an "s", so we say "Good birdie" and he
replies, "Want a nut."
Well, I don't want him sitting there using
our limited amount of time to eat a nut, so
I tell him to wait, and I ask, "What sound
is green?" Alex answers, "Ssshh." He's
right, it's "sh," and we go through the
routine again: "Good parrot." "Want a nut."
"Alex, wait. What sound is orange?" "ch."
"Good bird!" "Want a nut." We're going on
and on and Alex is clearly getting more and
more frustrated. He finally gets very slitty-eyed
and he looks at me and states, "Want a nut.
Nnn, uh, tuh."
Not only could you imagine him thinking,
"Hey, stupid, do I have to spell it for
you?" but the point was that he had leaped
over where we were and had begun sounding
out the letters of the words for us. This
was in a sense his way of saying to us, "I
know where you're headed! Let's get on with
it," which gave us the feeling that we were
on the right track with what we were doing.
These kinds of things don't happen in the
lab on a daily basis, but when they do, they
make you realize there's a lot more going on
inside these little walnut-sized brains than
you might at first imagine.
