Darwin's Island (12 page)

His favourite pet is back at the centre of the emotional stage. The world has four hundred million dogs and the efforts of their owners and the wonders of science have transformed the creatures into a gigantic experiment on the biology of sentiment. Even in the brief period since modern breeds began to emerge in Victorian times dogs have undergone large - and inherited - changes in temperament.

Men long ago began to use dogs in the hunt. They soon learned to choose those with their own special abilities - to track, to run, to squat into a ‘point’ position when prey is spotted, or to bite and tear or recover corpses - as parents for the next generation. Such remnants of the chase live on in the behaviour of Bloodhounds, Pointers, Setters, Retrievers and Bull Terriers. Herding dogs such as Border Collies stalk a sheep and do not bite it, but those used to control larger animals - like the Corgis once used with cattle - go further through the sequence and snap at their charges. Pit Bulls complete the job and are vicious creatures that will hold a bull by the nose and as a side-effect sometimes kill their owners. Guard dogs such as Pyrenean Mountain Dogs, whose job is to frighten off predators, have given up the hunt sequence altogether. They play like huge puppies and show little interest in their herds, but their conduct is odd enough to persuade wolves to stay away. Such differences emerge from inherited variation in behaviour within the common ancestors of each breed, from new genetic errors as the generations succeed each other, and from the accumulation of change by human choice.

One way to assess a dog’s personality is to startle it with the appearance of a stranger. Does the animal play with the visitor, back off, sniff him or chase him out of the room? Does a sudden noise anger the beast, terrify it or leave it unmoved? Other tests include the ability to sit still, to cope with solitude without whining or panic, to run through a maze or to find hidden food.

Cocker Spaniels are calm and obey orders, while Basenjis are nervous and almost impossible to train. Crosses between the two suggest that the difference in their nature is inborn, for the offspring have a range of talents, intermediate between each parent. A survey of ten thousand German Shepherds and Rottweilers in Sweden showed, within each type, a shared inheritance of excitability, a tendency to wag the tail and a need to bark, while aggression appears to be under separate control. In an echo of
Expression
’s principle that antithetical emotions are expressed as mirror images, variation in all those capacities depends on just how shy or how bold a particular breed might be.

As the dog-fanciers’ tastes became more refined, more and more specialised varieties emerged. Some began to develop habits that perturbed their owners. Mating like with like exposed rare and once-hidden genes, many of which had undesirable effects on personality. Some have parallels in the mental lives of men and women. In an echo of human obsessive-compulsive disorder, Bull Terriers chase their own tails for hours until they collapse, while Springer Spaniels may savage their masters as they fall into a sudden attack of uncontrolled rage. Certain families of Bassett Hounds suffer from a delusion reminiscent of paranoid schizophrenia and cower at the slightest noise. Some Dobermans, in contrast, fall into a heavy slumber after an unexpected snack. They have narcolepsy, a distressing and sometimes dangerous condition also found in people - and the dogs respond well to the drugs used to treat human patients.

The double helix reveals why some breeds diverge so much in personality. The first complete sequence came from a Boxer. The animal had less DNA than we do, with about twenty thousand genes altogether, several thousand fewer than ourselves. The hope is to find canine matches to our own disorders, and some have already emerged. The sleep problem in Dobermans involves damage to a certain receptor protein on the surface of brain cells - and the human equivalent is due to a fault in the same gene. No doubt our companions will help track down many more of the inherited errors behind our own mental illnesses, as they already have for conditions such as blindness. Charles Darwin would be proud.

 

Dogs are anomalous animals for their habits have been so subdivided by human effort that their mental universe is far from typical of a wild creature. Darwin soon moved on in his search for the roots of human emotion. He spent many hours in the company of our relatives in London Zoo. He had particular fun with the anatomy of amusement: ‘Young Orangs, when tickled, likewise grin and make a chuckling sound . . . as soon as their laughter ceases, an expression may be detected passing over their faces, which, as Mr. Wallace remarked to me, may be called a smile . . . I tickled the nose of a chimpanzee with a straw, and as it crumpled up its face, slight vertical furrows appeared between the eyebrows. I have never seen a frown on the forehead of the orang.’ He was particularly taken by the attempts of a monkey to court its own image in a mirror and by the antics of Jenny the orang-utan, who when teased with an apple on the wrong side of the bars ‘threw herself on her back, kicked and cried, precisely like a naughty child’.

Primates, like people, reveal their feelings on their faces. Someone who has never before seen a macaque can at once identify its mood as sad, happy or enraged, when shown the appropriate photograph. Many chimpanzee expressions have been named. They include the closed-mouth smile, its bared-teeth equivalent (which descends from an ancestor shared with our own smile), the bozo smile and the play face (a relative of human laughter), together with subtler statements of mood such as the stretched pout-whimper. Bonobos have an amused expression - and noise - which is uncannily like a guffaw. A German expert has identified an
Orgasmusgesicht
or ‘orgasm countenance’ in that species, although its existence in humans remains to be demonstrated. Gorillas are more impassive for they grin and make bozo faces but otherwise keep their thoughts to themselves unless they are simply furious.

Apes and monkeys can interpret their fellows’ moods to a considerable degree. Electronic avatars of chimps can have their looks manipulated to simulate pout-whimpers and the rest. When real animals are presented with their artificial comrades, they pick out different expressions at once, screaming faces best of all. They also show some insight into another’s emotions. If one animal sees another grimace in fear when it hears a sound it had learned to associate with an electrical shock, the observer will flinch when the buzzer goes off, even if it has never itself experienced the shock.

Humans are even better at sensing the moods of others. We are so aware of facial features that we often see them when they are not there (which explains the sad ape-like countenance in NASA’s pictures of the mountains on Mars). Two scrunched-up newspapers look much the same although their shapes are quite different, while two faces are seen as quite distinct although their shapes are almost the same. A simple bar code, the position of six stripes of dark and light - hair, forehead, eyebrows, nose, lips and chin - stores most of the data. Most people can recognise thousands of individuals and sense dozens of emotional states. Faces are important even to infants. Darwin noted that, when they were very small, his children spent long periods gazing at their mother. Now we know that a baby responds to a human countenance - even in a photograph - within minutes of birth.

Men, like apes, speak with their faces and use more or less the same language to do so. Angry people and angry gorillas bare their teeth and a frightened chimpanzee looks rather like a frightened person. For humans, as for apes, some expressions are ambiguous. Men and apes bare their teeth when amused but do the same when filled with terror.
Emotions
has a picture of a Sulawesi macaque as it grins in pleasure when stroked - but in other macaques the same gesture marks submission to a threat. Not all our grimaces are shared with our relatives, for apes never signal disgust and their noses, which are more sensitive than our own, remain unwrinkled even to a repulsive smell. A wide-open mouth is a threat in many primates but conveys no more than mild surprise for humans and while elephants weep, our closest kin do not.

Monkeys and apes reflect their moods in their postures as well as their expressions, and gorillas really do slap their chests in rage. Men, orangs, chimps and gorillas share the Italianate habit of waving their hands. Bonobos flap their wrists in irritation, point at themselves when they need a hug and stick out their palms when food is on offer. In a further nod at our common heritage, they prefer to signal with the right hand.

 

Our faces are more eloquent than are those of any other primate. Many pages of
The Expression of the Emotions
are devoted to the way they reflect their owners’ inner state. Some read rather quaintly nowadays: ‘the breach of the laws of etiquette, that is, any impoliteness or
gaucherie
, any impropriety, or an inappropriate remark, though quite accidental, will cause the most intense blushing of which a man is capable. Even the recollection of such an act, after an interval of many years, will make the whole body to tingle. So strong, also, is the power of sympathy that a sensitive person, as a lady has assured me, will sometimes blush at a flagrant breach of etiquette by a perfect stranger, though the act may in no way concern her.’ In the interests of science, modesty gave way to the search for truth: ‘Moreau gives a detailed account of the blushing of a Madagascar negress-slave when forced by her brutal master to exhibit her naked bosom’ and the sexual nature of that expression means that ‘Circassian women who are capable of blushing, invariably fetch a higher price in the seraglio of the Sultan.’ Mark Twain, himself an ardent evolutionist, put it well: ‘Man is the Animal that Blushes. He is the only one that does it—or has occasion to.’

Darwin was keen to discover whether signals such as the blush were the same in every human culture, or whether, like skin colour, they changed from place to place. He rejected the popular notion that different races had evolved from higher or lower forms of primate and that their mental lives and expressions of mood reflected this. Soon he began to accumulate a mass of anecdotes that made the case for the universal nature of facial cues. People also wrote to him about their dogs frowning in concentration or showing moral courage when their teeth were pulled. His correspondents included William Ewart Gladstone, who commented on statements about the Greek visage found in Homer, but also ‘Captain Speedy who long resided with the Abyssinians; Mr Bridges, a catechist residing with the Fuegians and Mr Archibald O. Lang of Coranderik, Victoria, a teacher at a school where aborigines, old and young, are collected from all parts of the colony’. One letter told of a Bengali boy with ‘a thoroughly canine snarl’. Its recipient fired off a series of questions to those servants of the Queen, sometimes to ludicrous effect (‘Mr B.F. Hartshorne . . . states in the most positive manner that the Weddas of Ceylon never laugh. Every conceivable incitive to laughter was used in vain. When asked whether they ever laughed, they replied: “No, what is there to laugh at?”’).

In spite of the Weddas, Darwin became certain that such signs were more or less universal across the globe: ‘The young and the old of widely different races, both with man and animals, express the same state of mind by the same movements.’ Hard as it is to believe, that observation was forgotten and for many years students of humankind assumed that expressions were determined by culture and were not coded into DNA (even if nobody found a place where people laughed in pain or screamed in welcome). Looks of anger, disgust, contempt, fear, joy, sadness and surprise all are universal. One tribe in New Guinea cannot separate expressions of fear from those of surprise - but in that society any intruder is a threat. People from different cultures do find it harder to identify each other’s guilty or shamefaced looks than they do a smile or an expression of terror, so that such subtle statements of mood may in part be learned. Even smiles are equivocal, for the beam, grin, smirk, snigger, simper and leer each convey a different message while people who smile too often come across as nervous rather than contented. Darwin, too, saw some ambiguities. The expression in a photograph of a man almost in tears was recognised by some as a ‘cunning leer’, a ‘jocund’ frame of mind or even as someone ‘looking at a distant object’.

 

Once he had established that most such signs were common to all mankind, Darwin set out to describe them. Measurement, he knew, is the first step in science (a lesson still ignored on the wilder shores of psychology) and he tried hard to give an impartial description of human features (‘The contraction of this muscle draws downwards and outwards the corners of the mouth, including the outer part of the upper lip . . . the commissure or line of junction of the two lips forms a curved line with the concavity downwards and the lips themselves are generally somewhat protruded’).

In today’s world of fraud, terrorism and identity cards such attempts to put facts on to faces have become an industry. Remarkable claims are made about the ability to identify people and to sense their states of mind. Some enthusiasts recognise thirty indications of anger and eight of sadness, with additional criteria based on how the subject holds his head. George W. Bush’s countenance was more or less blank whatever message he tried to put across, but his Department of Homeland Security has spent millions on machines that claim to detect when a terrorist is about to attack by the look on his countenance. Nobody denies that the expression of a Scotsman with a grievance is easy to distinguish from a ray of sunshine but such claims go too far.

The face says a lot about how we feel, but - as in apes - the body adds information to the stream of emotional cues: a man with raised fists is not about to make a visitor welcome. Psychologists tend, for practical reasons, to use pictures of faces alone. That can be a mistake. An image of a man with a disgusted expression taken from a modern catalogue of facial poses is interpreted as manifesting revulsion when superimposed on to a body holding a pair of dirty underpants - but as a look of anger when added to a torso with fists raised, or of triumph when stuck on to the beefy frame of a body-builder. The same photograph shown against the background of a cemetery is interpreted in a different way than when seen against a neutral surface. For students of the emotions, the assumption of simplicity can confuse results taken from the most complicated machines.