麻豆传媒

I HAVE a confession to make. I鈥檓 not a great dog lover. I simply can鈥檛 trust
a designer wolf. You may see man鈥檚 best friend, but I see a wild animal that has
inveigled its way into our homes and hearts. Sure, it can look cute. But I鈥檝e
always suspected that this beast might leap at my throat without a second
thought. After all, dogs just don鈥檛 understand that such behaviour is socially
unacceptable. Or do they?

It turns out that far from being an interloper and socially inept, the dog is
the product of tens of thousands of years of evolution in a very particular
environment鈥攐ur homes.

In recent years, evidence has emerged that dogs and humans have been living
together for much longer than anyone ever expected. Genetic evidence suggests
that we began to domesticate dogs while we were still hunter-gatherers, living
in caves and mastering the first grunts of language (see 鈥淣ew tricks and old
dogs鈥�). Researchers are just starting to reveal how this strange partnership has
shaped the way canines think and behave. 鈥淭he dog鈥檚 natural environment is the
human family or other human social settings,鈥� says Vilmos Cs谩nyi from
E枚tv枚s Lor谩nd University in Budapest.

Because humans and dogs evolved together he believes that we share certain
patterns of thought that allow us to live together. 鈥淒ogs are interested in the
emotional and intentional content of the human mind and they are able to learn
and to maintain the rules of human social settings,鈥� says Cs谩nyi. So
while others look to apes to shed light on social cognition, his team is
pioneering the study of dogs.

One of the first things they did was to investigate the bond between humans
and their pooches, to see how like a family member they really are. Dogs and
their owners are clearly emotionally attached, and selective breeding has
favoured infantile canine features. But, soppiness aside, does the relationship
between the two species really resemble the bond between a human parent and
child? To find out, J贸zsef Top谩l, 脕dam Mikl贸si and other
researchers from Cs谩nyi鈥檚 lab gave dogs the 鈥渟trange situation test鈥�,
originally devised to study the special bond or attachment that exists between
an infant and its mother or primary carer.

A securely attached baby behaves in a characteristic way in a strange
situation. Provided the mother is nearby, the infant shows little fear and is
happy to explore a new environment. When she leaves, the infant becomes
distressed but will usually settle with a stranger. The preference for the
mother is clear, however, when she returns and the baby is eager to greet
her.

Top谩l and Mikl贸si tested how 51 dogs responded to a similar
strange situation. The dogs were keen to play and explore in an unfamiliar room,
as long as their owner was there. When the owner left, the dogs didn鈥檛 play so
much and showed other signs of anxiety such as barking and waiting by the door.
Even if they eventually settled, all well-attached dogs greeted their returning
owners enthusiastically. 鈥淚t seems that dogs and infants behave very similarly,鈥�
says Mikl贸si, 鈥渁nd we think this is a result of evolutionary
诲辞尘别蝉迟颈肠补迟颈辞苍.鈥�

Cs谩nyi says there are two stages to forming this relationship. First,
comes a form of imprinting. If 6 to 12-week-old puppies come into contact with
people, their innate capacity to bond leads them to accept humans as a member of
their own species. Thereafter a dog can develop an attachment to any person who
shows it affection.

The researchers believe that the attachment to people might explain why dogs
sometimes appear stupid. Back in 1980, Harry Frank from the University of
Michigan-Flint, described how a wolf that could not be trained to sit on command
learned to manipulate a complicated door catch simply by watching another wolf
open it. But trained dogs couldn鈥檛 master the catch even after years of seeing
the door open and close. Frank concluded that through domestication dogs become
obedient and trainable while losing some cognitive abilities such as problem
solving. They have a decreased capacity for insight because throughout their
evolution human intervention has detached them from the consequences of their
actions.

Many people believe that any domestic animal is not as intelligent as its
wild relative. Dogs certainly have smaller brains for their body size than
wolves, particularly in the areas associated with vision and olfaction. But as
Mikl贸si points out, domestication is not necessarily to blame. One likely
ancestor of dogs, the small Asiatic wolf, had a smaller brain than other wolves.
What鈥檚 more, dogs don鈥檛 seem to have lost other mental abilities that would have
helped their ancestors hunt in packs. They understand object
permanence鈥攖hat things don鈥檛 just disappear even when they can no longer
see them. 鈥淒ogs are maybe at a similar level in this ability as apes,鈥� says
Mikl贸si. And they are capable of making mental maps to allow them to find
new routes through familiar territory.

Top谩l and Mikl贸si suspected that the poor problem-solving
ability of canines did not stem from a loss of mental abilities during their
evolution, but from the way an individual dog鈥檚 behaviour is shaped by its
relationship with its owners and by training. The stronger the attachment
between a dog and its owner, the researchers suggested, the more likely the pet
was to behave in a socially dependent way, relinquishing its powers of
independent thought and action.

To test the idea they asked 28 owners to fill in a questionnaire showing the
extent of their anthropomorphic attitudes to their dog. Questions included, 鈥淗ow
often do you allow the dog into your bed?鈥�, 鈥淒o you celebrate your dog鈥檚
birthday?鈥� and 鈥淭o what extent does your dog identify with your emotions?鈥� The
dogs were then given a problem to solve. They had to work out that they could
get a food reward by pulling on the handles of plastic dishes that protruded
from underneath a wire fence.

Sure enough, the more intimate the bond between dog and owner, the worse the
animal at solving the problem. But the differences disappeared as soon as the
owners encouraged their dogs to get the food. 鈥淒ogs with an intimate bond did
not perform worse but showed 鈥榙ependent鈥� behaviour,鈥� says Mikl贸si. 鈥淚t is
not that they don鈥檛 understand the problem.鈥�

Cs谩nyi and his team can back up this claim with further evidence from
their studies of interactions between blind people and guide dogs. 鈥淚n this
case, we find the best problem-solving dogs are those that are strongly attached
to their blind masters,鈥� says Cs谩nyi. Here the bond allows a dog to
cooperate with a human to negotiate difficult situations. So, although guide
dogs are trained to take control, the researchers found that once an animal
develops a bond with its master, it hands over the decision making only to step
in when the need arises.

Until now only humans were supposed to be capable of this kind of
sophisticated cooperation, where the initiative is constantly shifting between
two parties. Other animals only work together where they share interests and
objectives, such as those hunting in packs, or defending young offspring.

Obeying the rules

In Cs谩nyi鈥檚 view, domestication has in fact increased the dog鈥檚
cognitive abilities, not reduced them as Frank believes. By selecting
individuals that form strong attachments and are tractable, we have produced an
animal that is genetically predisposed to learn and obey rules.

While this is central to the guide dog鈥檚 abilities, it also means all dogs
can fit into their particular social environment. Even without formal training,
dogs become socialised simply by being with people. They have a talent for
working out the underlying rules. 鈥淭hey easily extract them from games and from
observing other dogs or humans,鈥� says Cs谩nyi.

Marc Bekoff from the University of Colorado has studied how dogs, wolves and
coyotes play. 鈥淎ll animals learn certain codes of conduct about their own
species鈥� morality through play,鈥� he says. 鈥淚 think dogs learn codes of conduct
from humans through dog/human play.鈥� They learn the ground rules for acceptable
behaviour, such as how hard they can bite without harming. And, like any animal,
when dogs play, they hone the behaviours they will need elsewhere.

There is little research into the evolutionary effects of such interactions
between dogs and humans, but Bekoff suspects that they have enriched the mental
life of dogs. A study in his lab reveals that playful interactions between
puppies are much more varied than those between young wolves or coyotes. He
thinks dogs have evolved more varied forms of behaviour because of the
sophisticated games people play with their pets and the selection for dogs that
are good at such games. 鈥淚t would feed over into other areas,鈥� says Bekoff. 鈥淚n
general ways it would make the dog more cognitive.鈥�

One area where human contact has certainly enhanced the mental capacity of
dogs is communication. Mikl贸si and his colleagues showed that dogs can
learn to respond to subtle human gestures. The pets could retrieve hidden food
items when prompted by their owner pointing, bowing, nodding, turning their head
and even just glancing towards the hiding place. It may sound simple, but no
other animal鈥攏ot even chimps鈥攑erforms so well.

The researchers believe that dogs really do understand what gestural cues
mean. Rhesus monkeys can find a hidden object that a human is pointing
to鈥攂ut only if the distance between the reward and the end of the finger
is less than 20 centimetres. They don鈥檛 seem to understand about pointing, but
instead learn that an outstretched finger may signal that there is food
nearby.

In Mikl贸si鈥檚 study the distance between gesture and reward did not
affect a dog鈥檚 success. Also, because the cue was given before the dogs were
allowed to search for food, there was no way they could simply follow the
movement of the gesture. Instead, Mikl贸si suggest, dogs seem to be
drawing a mental line between the finger and the reward. 鈥淲e think this is the
first step to argue that dogs understand that we are communicating something to
迟丑别尘.鈥�

Last year, researchers at Emory University in Atlanta confirmed the findings,
and repeated the experiments using dogs to send gestural cues to other dogs.
Brian Hare and Michael Tomasello found that while a six-month-old dog could not
understand the human gestures, it could respond to cues from another dog. This
pattern was reversed in four-year-old dogs. They argue that perhaps dogs have an
innate ability to read gaze cues from each other which they learn to extend to
people, while, for some reason, losing that capacity with their own species.
鈥淒ogs are genetically selected for their ability to tune in to humans,鈥� says
Tomasello, who is now at the Max Planck Institute in Leipzig.

Mikl贸si wanted to find out if dogs could send signals to people as
well as receive them. He found that when the pets knew where a reward was
hidden, they would make a noise to attract their owners and alternate their gaze
between the human and the hiding place. Mikl贸si interprets this behaviour
as 鈥渟howing鈥�. 鈥淒ogs are able to do the same as human infants and apes,鈥� he says.
鈥淲hat is behind this could be a kind of conditioning or a higher mental
process.鈥� Mikl贸si believes it is the latter. He argues that if gaze
alternation was simply a learned response the behaviour would not be universal.
Also, autistic children鈥攚ho lack a social sense鈥攄o not behave in
this way.

Tomasello takes a more sceptical view. 鈥淕aze alternation can mean different
things and I don鈥檛 think it means dogs are pointing,鈥� he says. 鈥淚 think they are
looking back to check and see whether you are coming.鈥� He has found that goats
also show this behaviour. 鈥淚 think gaze alternation is a general mammalian
ability, but the dogs are really tuned in,鈥� he says.

Symbols and signals

Now Cs谩nyi鈥檚 group is looking at dogs鈥� grasp of language. On average,
they found that mature pets understand 40 expressions, mostly signalling
actions. The range was between 7 and 80. 鈥淭heir understanding is different from
ours,鈥� says Cs谩nyi. 鈥淲e use words as symbols, they use words as signals
mainly.鈥� So, for example, dogs can extract simple information such as whether
they will be going for a walk and who will be taking them. It鈥檚 not clear how
they do it, but the ability can鈥檛 be explained by simple conditioning because
these words are embedded in long sentences, and hearing the word is not
immediately followed by going for a walk.

The remarkable social skills of dogs are understandable given that they are
adapted to the same environment as we are. 鈥淭he root of human evolution was
crowding,鈥� says Cs谩nyi. 鈥淲e do not know exactly why, but early humans
started to lump together, which created a complex behavioural problem to be
solved.鈥� He argues that communication, social bonding, following rules and
cooperation have evolved in people and dogs so that both species can cope with
this unusual setting. In addition, humans have the ultimate social glue,
empathy鈥攚e can see into one another鈥檚 minds. To say that dogs possess
similar insight is highly controversial, yet Cs谩nyi and others claim that
they do.

Most researchers accept that only animals that can recognise themselves in a
mirror are self-aware, allowing them to empathise, sympathise and attribute
intent and emotions in others. Dogs do not pass the test. And imagine removing
porcupine quills from your dog鈥檚 nose. Ouch! Yet another dog watching this
operation would be oblivious to the suffering, according to Gordon Gallup from
the State University of New York at Albany, who invented the mirror test. He
argues that because dogs have no sense of self, they cannot use their experience
of pain to attribute painful experiences to others.

But Cs谩nyi suggests that dogs can perceive when a person or another
dog is in danger and empathise with the emotional state of people who are sad or
ill. Bekoff agrees. In his forthcoming book on animal emotions, he recounts the
story of a dog who saved the life of his canine companion by awaking their owner
to let him know that the second dog was ill. Bekoff also tells a tale about his
own dog, Jethro, who adopted an orphaned rabbit and, years later, rescued an
injured bird. 鈥淚 think Jethro is a truly compassionate soul,鈥� writes Bekoff. 鈥淗e
could easily have gulped each down with little effort. But you don鈥檛 do that to
friends, do you?鈥�

Jeffrey Masson, author of Dogs never lie about love, has no doubt
that dogs empathise with humans. 鈥淚f they鈥檙e not self-aware, how come they can
appear so guilty?鈥� he asks. Cs谩nyi even goes so far as to compare canine
attachment with human love鈥攅mpathy incarnate. Masson believes that dogs
could teach us a thing or two about love and, indeed, may already have done so.
Dogs have been part of our evolutionary environment, just as we have been part
of theirs. 鈥淭here may be mutual influences,鈥� he says.

Canine remains at human burial sites led researchers to suspect that dogs
became domesticated around the time that our nomadic hunter-gatherer ancestors
settled down to grow crops, around 14 000 years ago, long before we acquired
goats, cattle and sheep. But in 1997, Carles Vil谩 and researchers in
Robert Wayne鈥檚 lab at the University of California at Los Angeles blew this idea
wide open.

They compared mitochondrial DNA from 67 breeds of dogs with that from wolves,
coyotes and jackals. The studies revealed at least four separate lines of
descent from dogs back to wolves, showing that there were at least four
successful attempts to domesticate them. The real surprise, though, was the high
level of genetic variation between different breeds. 鈥淭he mitochondrial DNA data
suggest very clearly that the diversity found in dogs might have an origin much
older than 14 000 years,鈥� says Vil谩. Knowing the rate at which these DNA
sequences change, he estimated that the split with wolves鈥攁nd hence
domestication鈥攐ccurred around 135 000 years ago.

If this is right, domestication started at around the time that our own
species evolved, and perhaps not long after our ancestors acquired language. Pet
ownership could well pre-date such cultural mainstays as art and the practice of
burying the dead. But even Vil谩, now at Uppsala University in Sweden,
accepts that the date is controversial. Wayne hopes new research will pin it
down. 鈥淲e are examining ancient breeds, such as the Xolo, ancient remains from
the Middle East and South America of the earliest dogs and nuclear genetic
markers,鈥� he says.