thought the mental capacities of animals and people differed
only in degree, not kind - a natural conclusion to reach when
armed with the radical new belief that the one evolved from the
His last book,
"The Expression of Emotions in Man and Animals", examined joy,
love and grief in birds, domestic animals and primates as well
as in various human races.
But Darwin's attitude to animals -
easily shared by people in everyday contact with dogs, horses,
even mice - ran contrary to a long tradition in European
thought which held that animals had no minds at all...
This way of thinking
stemmed from the argument of René Descartes, a great 17th-century
philosopher, that people were creatures of reason, linked to the
mind of God, while animals were merely machines made of
flesh - living robots which, in the words of Nicolas
Malebranche, one of his followers,
pleasure, cry without pain, grow without knowing it: they
desire nothing, fear nothing, know nothing."
The organism itself
remained a black box:
unobservable things such as emotions or
thoughts were beyond the scope of objective inquiry
For much of the 20th century biology cleaved closer
to Descartes than to Darwin.
Students of animal
behavior did not rule out the possibility that animals had minds
but thought the question almost irrelevant since it was
impossible to answer. One could study an organism's inputs (such
as food or the environment) or outputs (its behavior).
But the organism
itself remained a black box: unobservable things such as
emotions or thoughts were beyond the scope of objective inquiry.
As one such
"behaviorist" wrote in 1992,
conscious thought to animals should be strenuously avoided
in any serious attempt to understand their behavior, since
it is untestable [and] empty…"
By then, though,
there was ever greater resistance to such strictures.
In 1976 a professor
at Rockefeller University in New York,
had taken the bull by the horns (leaving aside what the bull
might have felt about this) in a book called "The Question of
He argued that
animals could indeed think and that their ability to do this
could be subjected to proper scientific scrutiny.
In the past 40 years a wide range of work both in the field and
the lab has pushed the consensus away from strict behaviorism
and towards that Darwin-friendly view.
Progress has not been
easy or quick; as the behaviorists warned, both sorts of
evidence can be misleading.
Laboratory tests can
be rigorous, but are inevitably based on animals which may not
behave as they do in the wild. Field observations can be
dismissed as anecdotal. Running them for years or decades and on
a large scale goes some way to guarding against that problem,
but such studies are rare.
No animals have all the attributes of human minds; but almost
all the attributes of human minds are found in some animal or
Nevertheless, most scientists now feel they can say with
confidence that some animals process information and express
emotions in ways that are accompanied by conscious mental
They agree that
animals, from rats and mice to parrots and humpback whales, have
complex mental capacities:
that a few species have attributes
once thought to be unique to people, such as the ability to give
objects names and use tools
that a handful of animals -
primates, corvids (the crow family) and cetaceans (whales and
dolphins) - have something close to what in humans is seen as
culture, in that they develop distinctive ways of doing things
which are passed down by imitation and example.
No animals have all
the attributes of human minds; but almost all the attributes of
human minds are found in some animal or other.
Consider Billie, a wild bottlenose dolphin which
got injured in a lock at the age of five. She was taken to an
aquarium in South Australia for medical treatment, during which
she spent three weeks living with captive dolphins which had
been taught various tricks.
She herself, though,
was never trained.
After she was
returned to the open sea local dolphin-watchers were struck to
see her "tailwalking" - a move in which a dolphin stands up
above the water by beating its flukes just below the surface,
travelling slowly backwards in a vaguely Michael Jackson manner.
It was a trick that
Billie seemed to have picked up simply by watching her erstwhile
pool mates perform. More striking yet, soon afterwards five
other dolphins in her pod started to tailwalk, though the
behavior had no practical function and used up a lot of energy.
Such behavior is hard to understand without imagining a mind
that can appreciate what it sees and which intends to mimic the
actions of others (see "The imitative dolphin").
That in turn implies
things about the brain. If you had to take a bet on things to be
found in Billie's brain, you'd be well advised to put money on
"mirror neurons". Mirror neurons are nerve cells that fire when
the sight of someone else's action triggers a matched response
- they seem to be what makes yawning contagious.
A lot of learning may
require this way of linking perception to action - and it
seems that, in people, so may some forms of empathy.
Mirror neurons are important to scientists attempting to find
the basis of the way the human mind works, or at least to find
correlates of that working, in the anatomy of human brains. The
fact that those anatomical correlates keep turning up in
non-human brains, too, is one of the current reasons for seeing
animals as also being things with minds.
There are mirror
neurons; there are spindle cells (also called
von Economo neurons) which play
a role in the expression of empathy and the processing of social
have parts corresponding to Broca's area and Wernicke's area
which, in people, are associated with language and
Brain mapping reveals
that the neurological processes underlying what look like
emotions in rats are similar to those behind what clearly are
emotions in humans.
As a group of
neuroscientists seeking to sum the field up put it in 2012,
"Humans are not
unique in possessing the neurological substrates that
generate consciousness. Non-human animals, including all
mammals and birds, and many other creatures…also possess
these neurological substrates."
But to say that
animals have a biological basis for consciousness is not the
same as saying they actually think or feel.
Here, ideas from the
law may be more helpful than those from neurology.
When someone's state
of being is clearly impaired by a calamity of some sort, it can
fall to the courts to decide what level of legal protection
In such cases courts
apply tests such as:
Is he or she
recognize others as individuals?
regulate his own behavior?
experience pleasure or suffer pain (that is, show
Such questions reveal
a lot about animals, too.
The most common test of self-awareness is the ability to
recognize yourself in a mirror. It implies you are seeing
yourself as an individual, separate from other beings.
The test was formally
developed in 1970 by Gordon Gallup, an American
psychologist, though its roots go back further; Darwin wrote
about Jenny, an orangutan, playing with a mirror and being
"astonished beyond measure" by her reflection.
Dr Gallup daubed an
odorless mark on the face of his subjects and waited to see how
they would react when they saw their reflection. If they touched
the mark, it would seem they realized the image in the mirror
was their own, not that of another animal. Most humans show this
ability between the ages of one and two.
Dr Gallup showed that
chimpanzees have it, too. Since then, orangutans, gorillas,
elephants, dolphins and magpies have shown the same ability.
Monkeys do not; nor do dogs, perhaps because dogs recognize each
other by smell, so the test provides them with no useful
Recognizing yourself is one thing; what of recognizing others -
not just as objects, but as things with purposes and desires
like one's own, but aimed at different ends. Some animals
clearly pass this test too.
is a chimpanzee in Furuvik zoo in Sweden.
In the 2000s
zookeepers noticed that he was gathering little stockpiles of
stones and hiding them around his cage, even constructing covers
for them, so that at a later time he would have something to
throw at zoo visitors who annoyed him. Mathias Osvath of Lund
University argues that this behavior showed various types of
remember a specific event in the past (being annoyed by
visitors), prepare for an event in the future (throwing
stones at them) and mentally construct a new situation
(chasing the visitors away).
understand that they can manipulate the beliefs of others; they
frequently deceive each other in competition for food
Philosophers call the ability to recognize that others have
different aims and desires a "theory of mind". Chimpanzees have
this. Santino seemed to have understood that zookeepers would
stop him throwing stones if they could.
He therefore hid the
weapons and inhibited his aggression:
he was calm when
collecting the stones, though agitated when throwing them.
An understanding of
the capabilities and interests of others also seems in evidence
at the Centre for Great Apes, a sanctuary in Florida, where male
chimpanzees living with Knuckles, a 16-year-old with cerebral
palsy, do not subject him to their usual dominance displays.
understand that they can manipulate the beliefs of others; they
frequently deceive each other in competition for food.
Another test of legal personhood is the ability to experience
pleasure or pain - to feel emotions. This has often been taken
as evidence of full sentience, which is why Descartes's
followers thought animals were unable to feel, as well as
an Australian philosopher and doyen of "animal rights", argues
that, of all the emotions, suffering is especially significant
because, if animals share this human capacity, people should
give consideration to animal suffering as they do to that of
their own kind.
Animals obviously show emotions such as fear.
But this can be taken
to be instinctual, similar to what happens when people cry out
in pain. Behaviorists had no trouble with fear, seeing it as a
conditioned reflex that they knew full well how to create.
The real question is
whether animals have feelings which involve some sort of mental
This is not easy. No
one knows precisely what other people mean when they talk about
their emotions; knowing what dumb beasts mean is almost
That said, there are
some revealing indications - most notably, evidence for what
could be seen as compassion.
Some animals seem to display pity, or at least concern, for
diseased and injured members of their group. Stronger chimps
help weaker ones to cross roads in the wild. Elephants mourn
their dead (see "The grieving elephant").
In a famous
experiment, Hal Markowitz, later director of the San
Francisco zoo, trained Diana monkeys to get food by putting a
token in a slot. When the oldest female could not get the hang
of it, a younger unrelated male put her tokens in the slot for
her and stood back to let her eat.
There have also been observations of animals going out of their
way to help creatures of a different species.
In March 2008,
Moko, a bottlenose dolphin, guided two pygmy sperm
whales out of a maze of sandbars off the coast of New Zealand.
The whales had seemed
hopelessly disoriented and had stranded themselves four times.
There are also well-attested cases of humpback whales rescuing
seals from attack by killer whales and dolphins rescuing people
from similar attacks.
On the face of it,
this sort of concern for others looks moral - or at least
In a few examples the protecting animals have been seen to pay a
price for their compassion. Iain Douglas-Hamilton, who studies
elephants, describes a young female which had been so severely
injured that she could only walk at a snail's pace.
The rest of her group
kept pace with her to protect her from predators for 15 years,
though this meant they could not forage so widely.
As long ago as 1959,
Russell Church of Brown University set up a test which
allowed laboratory rats in half of a cage to get food by
pressing a lever. The lever also delivered an electric shock to
rats in the other half of the cage. When the first group
realized that, they stopped pressing the lever, depriving
themselves of food.
In a similar test on
rhesus monkeys reported in the American Journal of Psychiatry in
1964, one monkey stopped giving the signal for food for 12 days
after witnessing another receive a shock.
There are other
examples of animals preferring some sort of feeling over food.
In famous studies by an American psychologist, Harry Harlow,
rhesus monkeys deprived of their mothers were given a choice
One was made of wire
and had a feeding bottle, the other was cloth, but without food.
The infants spent almost all their time hugging the cloth
If animals are self-aware, aware of others and have some measure
of self-control, then they share some of the attributes used to
define personhood in law. If they display emotions and feelings
in ways that are not purely instinctive, there may also be a
case for saying their feelings should be respected in the way
that human feelings are.
But the attribute
most commonly thought of as distinctively human is language.
Can animals be said
to use language in a meaningful way?
Animals communicate all the time and don't need big brains to do
so. In the 1940s Karl von Frisch, an Austrian ethologist,
showed that the "waggle dances" of honeybees pass on information
about how far away food is and in what direction.
Birds sing long,
complex songs either to mark territory or as mating rituals. So
do pods of whales (see "The singing whales"). It is hard,
though, to say what information, or intention, goes into all
The bees are more
likely to be automatically downloading a report of their recent
travels than saying,
The vocalizations of,
say, vervet monkeys have more to them.
different alarm calls for different predators, demanding
different responses. There is one for leopards (skitter up into
the highest branches), for eagles (hide in the undergrowth) and
for snakes (stand upright and look around). The monkeys need to
recognise the different calls and know when to make which one.
Animals brought up
with humans can do much more. Chaser, a border
collie, knows over 1,000 words. She can pull a named toy from a
pile of other toys.
This shows that she
understands that an acoustical pattern stands for a physical
a linguist, once said only people could do that. Remarkably, if
told to fetch a toy with a name she has not heard before placed
in a pile of known, named objects, she works out what is being
another border collie, will bring back a photograph of
something, suggesting she understands that a two-dimensional
image can represent a three-dimensional object.
More impressive still are animals such as Washoe, a female
chimpanzee which was taught sign language by two researchers at
the University of Nevada. Washoe would initiate conversations
and ask for things she wanted, like food.
But evidence that
many animals can, when brought up with humans, tell their
thoughts to others using a human language is not quite the same
as saying they use language as people do.
Few have a smidgen of
grammar, for example - that is, the ability to manipulate and
combine words to create new meanings.
It is true that
dolphins in captivity can distinguish between "put the ball in
the hoop" and "bring the hoop to the ball". Alex, an African
grey parrot, combined words to make up new ones: he called an
apple a "bannery", for example, a mixture of banana and cherry
(see "The chatterbox parrot").
But these are
exceptional cases and the result of intense collaboration with
humans. The use of grammar - certainly a complex grammar -
has not been discerned in the wild.
have no equivalent to the narratives that people tell one
If language can still be claimed as uniquely human, can anything
else? Until recently, culture would have been held up as a
second defining feature of humanity.
Complex ways of doing
things which are passed down not by genetic inheritance or
environmental pressure but by teaching, imitation and conformism
have been widely assumed to be unique to people. But it is
increasingly clear that other species have their own cultures,
In "The Cultural Lives of Whales and Dolphins", Hal Whitehead
of Dalhousie University, Nova Scotia, and Luke Rendell of
the University of St Andrews, in Scotland, argue that all
cultures have five distinctive features:
technology; teaching and learning; a moral component, with
rules that buttress "the way we do things" and punishments
for infraction; an acquired, not innate, distinction between
insiders and outsiders; and a cumulative character that
builds up over time.
together allow individuals in a group to do things that they
would not be able to achieve by themselves.
For the first feature, look no further than the crow. New
Caledonian crows are the champion toolmakers of the animal
kingdom. They make hooks by snipping off V-shaped twigs and
nibbling them into shape.
They fashion Pandanus
leaves into toothed saws. And in different parts of the island
they make their tools in different ways.
Studies by Gavin
Hunt of the University of Auckland showed that the hooks and
saws in two sites on New Caledonia differed systematically in
size, in the number of cuts needed to make them and even
according to whether they were predominantly left-handed or
To the extent that
culture means "the way we do things around here", the two groups
of crows were culturally distinct.
Chimpanzees are now known to manipulate over two dozen
implements: clubs to beat with, pestles to grind with, fly
whisks, grass stalks with which to fish for termites, spongy
leaves to soak up water, rocks as nutcrackers. Like New
Caledonian crows, different groups use them slightly
of Cambridge University argues that the tool sets of chimpanzees
in western Tanzania are just as complex as the simplest human
tools, such as early human artifacts found in east Africa or
indeed those used in historic times by native peoples in
The skill needed to make and use tools is taught. It is not the
only example of teaching that animals have to offer.
Meerkats feed on
scorpions - an exceptionally dangerous prey which you cannot
learn to hunt by trial and error. So older meerkats teach
younger ones gradually. First they incapacitate a scorpion and
let the young meerkat finish it off.
Then they let their
students tackle a slightly less damaged specimen, and so on in
stages until the young apprentice is ready to hunt a healthy
scorpion on its own.
Pretty much all meerkats do this. Elsewhere what is taught can
change, with just some animals picking up new tricks. As the
story of Billie the tailwalker implies, whales and dolphins can
learn fundamentally new behaviors from each other. In 1980, a
humpback whale started to catch fish off Cape Cod in a new way.
It would slam its
flukes down on the surface of the water - lobtailing, as it is
known - then dive and swim round emitting a cloud of bubbles.
The prey, confused by the noise and scared of the rising circle
of bubbles, bunched themselves together for protection.
The whale would then
surge up through the middle of the bubble cloud with a mouth
full of fish.
Bubble feeding is a well known way for whales to freak out their
food; so is lobtailing. Making the first a systematic set-up to
the second, though, was apparently an innovation - and became
By 1989, just nine
years after the first Cape Cod whale started lobtail feeding,
almost half the humpbacks in the area were at it. Most were
younger whales which, since their mothers did not use the new
trick, could not have inherited it.
young whales copied the first practitioner, spreading the
technique through imitation. How the first one got the idea is a
mystery - as is the question of whether it is actually a
superior way of feeding, or merely an increasingly fashionable
Cultures rely not only on technologies, techniques and teaching
but on rules of accepted behavior.
That things should be
fair seems a widespread requirement among social animals.
At a canine research
centre at Eotvos Lorand University in Budapest, for example,
dogs frequently chosen to take part in tests are shunned by
It turns out that all
the dogs want to take part in these tests because they receive
human attention; those which are chosen too often are seen as
having got unfair advantage.
taking part in experiments keep track of the rewards they are
getting. If one is offered a poor reward (such as a slice of
cucumber), while another gets a tasty grape, the first will
refuse to continue the test. Chimpanzees do this, too.
Most cultures distinguish between outsiders and insiders and
animals are no exceptions. Orcas, also known as killer whales,
are particularly striking in this regard, having a repertoire of
calls which are distinctive to the pod in which they live, a
sort of dialect.
Dr Whitehead and Dr
Rendell compare them to tribal markings.
Orcas are unusual in
that different pods tend to feed on different prey and rarely
interbreed. Most of the time, pods studiously ignore each
another. But occasionally one will ferociously attack another.
This cannot have anything to do with competition for food or
of the Vancouver Aquarium attributes it to xenophobia - a
particularly extreme and aggressive way of distinguishing
between insiders and outsiders.
But if animals display four of the five attributes that go to
make up a culture, there is one they do not share. Perhaps the
most distinctive thing about human cultures is that they change
over time, building upon earlier achievements to produce
everything from iPhones and modern medicine to democracy.
Nothing like this has been observed in animals.
Particular aspects of
animal behaviour change in ways that might seem cultural, and
disruptive change is certainly possible.
In the 1990s, for
example, South African culling policies that saw the oldest
elephants shot and their children redistributed led to large
changes in their normally orderly matriarchal societies.
became abnormally aggressive, since there were no longer any
elders to rein them back. In other cases such disruption can
seem, anthropomorphically, not so bad (see "the peaceful
baboons"). But whether the shocks are good or bad, animal
societies have yet to show steady, adaptive change - any
with the oldest individuals - when drought struck Tarangire
national park in Tanzania in 1993 the elephant families that
survived best were those led by matriarchs which remembered the
severe drought of 1958 - but it goes to the graveyard with
There is a great deal more to learn about animal minds.
can pretty thoroughly be ruled out; learned toolmaking for some
species is now indubitable: but many conclusions are in the
middle, neither definitively in nor out.
Whether you accept
them depends partly on the standard of evidence required. If the
question of animal empathy were being tested in a criminal
court, demanding proof beyond reasonable doubt, you might
hesitate to find that it exists. If the trial were a civil one,
requiring a preponderance of evidence, you would probably
conclude that animals had empathy.
Using that standard, one can hazard three conclusions.
animals do have minds, The physiological evidence of brain
functions, their communications and the versatility of their
responses to their environments all strongly support the idea.
Primates, corvids and
cetaceans also have attributes of culture, if not language or
organized religion (though Jane Goodall, a noted
zoologist, sees chimps as expressing a pantheistic pleasure in
Next, animals' abilities are patchy compared with those of
Dogs can learn words
but do not recognize their reflections. Clark's nutcracker, a
member of the crow family, buries up to 100,000 seeds in a
season and remembers where it put them months later - but does
not make tools, as other corvids do.
focused abilities fit with some modern thinking about human
minds, which sees them less as engines of pure reason that can
be applied in much the same way to all aspects of life as
bundles of subroutines for specific tasks.
On this analysis a
human mind might be a Swiss army knife, an animal mind a
corkscrew or pair of tweezers.
This suggests a corollary - that there will be some dimensions
in which animal minds exceed humans.
Take the example of
Ayumu, a young chimpanzee who lives at the Primate
Research Institute of the University of Kyoto. Researchers have
been teaching Ayumu a memory task in which a random pattern of
numbers appears fleetingly on a touchscreen before being covered
by electronic squares.
Ayumu has to touch
the on-screen squares in the same order as the numbers hidden
Humans get this test
right most of the time if there are five numbers and 500
milliseconds or so in which to study them. With nine numbers, or
less time, the human success rate declines sharply.
Show Ayumu nine
numbers flashed up for just 60 milliseconds and he will
nonchalantly tap out the numbers in the right order with his
There are humans with so called eidetic, or flash, memories who
can do something similar - for chimps, though, this seems to
be the norm.
Is it an attribute
that chimps have evolved since their last common ancestor with
humans for some reason - or,
humans have lost over the same period of time?
how might it change what it is for a chimp to have a
is having minds in a society where everyone remembers
Animals might well
think in ways that humans cannot yet decipher because they are
too different from the ways humans think - adapted to sensory
and mental realms utterly unlike that of the human, perhaps
realms that have not spurred a need for language.
There is, for
example, no doubt that octopuses are intelligent; they are
ferociously good problem solvers. But can scientists begin to
imagine how an octopus might think and feel?
All that said, the third general truth seems to be that there is
a link between mind and society which animals display.
The wild animals with
the highest levels of cognition (primates, cetaceans, elephants,
parrots) are, like people, long-lived species that live in
complex societies, in which knowledge, social interaction and
communication are at a premium.
It seems reasonable
to speculate that their minds - like human ones - may well
have evolved in response to their social environment (see "The
And this may be what
allows minds on the two sides of the inter-species gulf to
Off Laguna, in southern Brazil, people and bottlenose dolphins
have fished together for generations. The dolphins swim towards
the beach, driving mullet towards the fishermen.
The men wait for a
signal from the dolphins - a distinctive dive - before
throwing their nets.
The dolphins are in
charge, initiating the herding and giving the vital signal,
though only some do this. The people must learn which dolphins
will herd the fish and pay close attention to the signal, or the
fishing will fail. Both groups of mammals must learn the
Among the humans,
these are passed down from father to son; among the dolphins,
from mother to calf.
In this example, how
much do the species differ?