Animal Communication!

As I listened from a beach-chair in the shade To all the noises that my garden made, It seemed to me only proper that words Should be withheld from vegetables and birds.

W.H. AUDEN

OBJECTIVES

In this chapter, you will learn: how animals communicate nonvocally

what types of signs are used in communication

how bees, birds, and nonhuman primates communicate

what arguments are made for and against linguistic ability in nonhuman primates

how the communication systems of humans and animals may be compared

Communicationthe passing on or exchange of informationdistinguishes what isliving from what is nonliving in nature. Communication is found even in the appar-ently passive world of plants; trees, for example, have been found to pass on informa-tion about advancing predators by means of chemical signals. Animals communicateamong themselves and with humans so effectively that they are often said to uselanguage. But the words communication and (human) language do not mean the samething. Human language is a specific way of communicating, but not just any form ofcommunication qualifies as language.

A question that therefore interests many linguists is whether animals makeuse of any system of communication that genuinely resembles or approximateshuman language. If animals communicate with a system that is structured like

e i g h t e e n

AnimalCommunication

Michael Dobrovolsky

Bedford/St. Martins 2010 18 -1

GRA_25552_ch18_online_001_038.qxd 7/1/09 10:27 AM Page 18-1

human language, then language as we know it is not the unique property of ourspecies. This chapter investigates the ways in which animal communication is likehuman language and the ways in which it is different.

1 Nonvocal CommunicationOne of the most striking things about animal communication is the variety of meansthrough which it is carried out. Animals communicate not only with sounds butwith scent, light, ultrasound, visual signs (see Figure 18.1), gestures, color, and evenelectricity. From the slime mold to the Kalahari barking gecko to the giant bluewhale, all living things communicate. Some nonvocal modes of communication aredescribed here.

Scent Chemicals used by animals specifically for communicative purposes arecalled pheromones. Pheromones are used by species as different as molds,insects, and mammals. A female moth signals its reproductive readiness throughthe release of a pheromone into the air. Only a few of these molecules need tobe sensed by a male moth for it to start flying zigzag upwind towards its poten-tial mate. Dogs and other canines leave a urine-based pheromone as an identifi-cation mark to stake out their territory, and many nonhuman primates havespecialized scent glands for the same purpose.

Light Probably the most well-known light user in North America is the firefly orlightning bug. This small flying beetle uses light flashes in varying patterns to sig-nal its identity, sex, and location. Different species of these insects have differentand distinguishing light patterns.

Electricity Certain species of eels in the Amazon River basin communicate theirpresence and territoriality by means of electrical impulses at various frequencies.Each species signals at a specific frequency range, and the transmitting frequen-cies, like those of radio and television stations, do not overlap.

Color The color (or color pattern) of many animals plays an important role intheir identification by members of their own species and other animals. Theoctopus changes color frequently and this coloring is used for a range of mes-sages that include territorial defense and mating readiness.

Posture This is a common communicative device among animals. Dogs, forexample, lower the front part of their bodies and extend their front legs whenthey are playful. They lower their whole bodies to the ground when they aresubmissive. Postural communication is found in both human and nonhumanprimates.

Gesture Humans wave their arms in recognition or farewell, dogs wag their tailsin excitement, and cats flick their tails when irritated. Many birds perform elab-orate gestures of raising and lowering the head or racing back and forth across thewater in their mating rituals. Some fish, such as the male stickleback, perform aseries of distinct movements in the water as part of their mating ritual.

18-2 C H A P T E R E I G H T E E N

Bedford/St. Martins 2010


Facial expressions These are specific types of communicative gestures. When amale baboon yawns, bares its fangs, and retracts its eyebrows, it is indicating awillingness to fight. A wide and recognizable variety of facial expressions is foundamong chimpanzees, a number of which are shown in Figure 18.1. Experimentshave shown that humans can classify the meanings of these expressions quiteaccurately. For example, when humans draw back the corners of their mouthsinto a smile, they are generally indicating cooperation. A nonhuman primatessmile also indicates nonaggressiveness.

A N I M A L C O M M U N I C AT I O N 18-3


Figure 18.1 Some chimpanzee facial expressions: a. anger; b. fear-anger; c. affection; d. frustration-sadness; e. playfulness

2 Communication Structure:The Study of SignsCertain common elements underlie the bewildering variety of communicativestrategies found in nature. An understanding of these elements is necessary for com-paring the differences and similarities among systems of communication.

2.1 SignsCommunication relies on using something to stand for something else. Words arean obvious example of this: you do not have to have a car, a sandwich, or yourcousin present in order to talk about themthe words car, sandwich, and cousinstand for them instead. This same phenomenon is found in animal communicationas well. Instead of fighting over territory, for example, many animals producesounds or make gestures that threaten and intimidate intrudersthe messagereplaces the attack. Birds utter warning calls that represent the presence of a threat.A threatening animal or human need not be seen by other birds before they takeflightperception of the warning call replaces visual perception of the threat.


Each of these things that stand for other things is technically known as a sign.The sign is a unit of communication structure that consists of two parts: a signifier,be it a word, a scent, a gesture, or an electrical frequency, and something signifiedthat exists in the real world and is mentally represented by the signs conceptual con-tent. The real world can be thought of as external, mental, or emotional, and so whatis signified by a sign can be as diverse as a tree, an abstract idea, a perception, or afeeling. Because their content is conceptual, all signs are associated with somemeaning, such as danger or item of furniture with legs and a flat top. Individualinstances of signs are called tokens. For example, in the sentence The baby threw therattle there are five word tokens, but only four signs; the occurs twice as a token, butit is the same sign in both instances. Figure 18.2 illustrates these distinctions.



Signified Signified

Real world referent

Tokenplant, having a trunk,

with leavesor needles

Sign

/t ri/

[ i ]

[t runderring i]

Figure 18.2 A sign

The SignifierA signifier is that part of a sign that stimulates at least one sense organ of the receiverof a message. The phonological component of the word tree, represented as /ti/ andpronounced [tunderring i] is a typical linguistic signifier. A signifier can also be a picture, aphotograph, a sign language gesture, or one of the many other words for tree in dif-ferent languages.

LANGUAGE MATTERS The Science of Semiotics

Semiotics, the study of signs, is a field of study that links many diversedisciplines, among them linguistics, anthropology, philosophy, zoology, genetics,literary study, and computer science. An understanding of signs is essential forunderstanding how messages are transmitted. So that we can understand signsbetter before proceeding to an analysis of animal communication, the next sec-tion examines their structure in detail. To find out more, read Daniel ChandlersSemiotics for Beginners at www.aber.ac.uk/media/Documents/S4B/.

The SignifiedThe signified component of the sign refers to both the real world object it representsand its conceptual content.


The first of these is the real world content of the sign, its extension or referent (seeChapter 6, Section 1.3) within a system of signs such as English, avian communication,or sign language. In our example, the referent is represented by a drawing becausethere is no room to include a real tree between the pages of this book. (Of course, thesignifier /ti/ could also have a picture of a tree as its referent.) It is easiest to think ofreferents as concepts or persons or things but they may be ideas or feelings as well.

The signified component of a sign also evokes an intension (see Chapter 6,Section 1.3) to users of the system in question. A word for tree evokes concepts thatprobably include plant, having a trunk, and bearing leaves or needles in theminds of speakers of any language who are familiar with trees. Some animals appearto conceptualize in terms of classes or categories as well. Certain monkeys, for exam-ple, distinguish among various types of predators on the basis of size, shape, andmotion (see Section 5.3 in this chapter).

2.2 Types of SignsSigns can be divided into three basic types, depending on (1) whether the signifiernaturally resembles its referent, (2) whether the signifier is directly linked with thereferent in a physical or mechanical sense, or (3) whether signifier and referent arearbitrarily associated.

Iconic SignsIconic signs, or icons, always bear some resemblance to their referent. A photo-graph is an iconic sign, as is a stylized silhouette of a female or a male on a rest-room door. A baboons open-mouth threat is iconic, resembling as it does the actof biting. Onomatopoeic words like buzz, splat, and squish in English and theircounterparts in other human languages are also iconic in that they somewhatresemble what they signify. Because of this inherent resemblance to these referents,icons are considered nonarbitrary signs (see Figure 18.3).



Figure 18.3 Some iconic tokens: a. open-mouth threat by a Japanese macaque (Macacafuscata); b. park recreation signs; c. onomatopoeic words in English


Icons are widespread in the communication systems of all animals. Many pos-tures and gestures that are critical to animal communication are iconic, as are thepostures and gestures used by humans. Human linguistic communication, however,does not make extensive use of iconic signs.

Indexical SignsAn indexical sign, or index, fulfils its function by pointing out its referent, typi-cally by being a partial or representative sample of it. Indexes are not arbitrary, sincetheir presence has in some sense been caused by their referent. For this reason it issometimes said that there is a causal link between an indexical sign and its referent.The track of an animal, for example, points to the existence of the animal by repre-senting a part of it. The presence of smoke is an index of fire.

Most important for our discussion here is a specific kind of indexical signcalled a symptomatic sign, or symptom. Symptomatic signs spontaneously conveythe internal state or emotions of the sender and thus represent the sender in anindexical manner. For example, the fact that our body temperature rises when weare ill is a spontaneous reflection of our internal state. When someone steps on ourfoot and we cry out, the cry is a spontaneous reflection of our internal state (sur-prise and pain) and thus constitutes a symptomatic sign.

Since symptomatic signs are spontaneous, we do not consider them to be delib-erately selected by the sender for purposes of communication. We do not choose tocry out in pain in the same way as we might, for example, decide to call our dwellingplace a house, home, dwelling, or residence in the appropriate circumstances. Sincesenders do not deliberately choose to transmit the sign, the message is assumed to beessentially beyond their control. As forms of communication, symptomatic signs aretherefore used primarily by the receiver of a message to assess the internal state ofthe sender.

Symbolic SignsSymbolic signs bear an arbitrary relationship to their referents and in this way aredistinct from both icons and indexes. Human language is highly symbolic in that thevast majority of its signs bear no inherent resemblance or causal connection to theirreferents, as the words in Figure 18.4 show.



Figure 18.4 Arbitrary sound-meaning correspondence in language

tako ?maz ?talo ?kum ?berat ?

No phonological property of the words in Figure 18.4 gives you any hint as to theirpossible meaning. (Tako means octopus in Japanese, maz is forest in Kabardian,talo is house in Finnish, kum means sand in Turkish, and berat means heavy inIndonesian.)


We encounter many other symbolic signs in everyday life. The octagonal shapeof a stop sign is symbolicit bears no inherent connection with the message it helpsto communicate. The colors used in traffic signals are symbolic as well; red has nomore inherent connection with the act of stopping than yellow.

Mixed SignsSigns are not always exclusively of one type or another. Symptomatic signs, for exam-ple, may have iconic properties, as when a dog spontaneously opens its mouth in athreat to bite. Symbolic signs such as traffic lights are symptomatic in that theyreflect the internal state of the mechanism that causes them to change color. Still, weclassify a sign according to its major property: if it resembles its referent, it is iconic;if it is linked to its referent in some causal way or represents it partially in somenonarbitrary way, it is indexical (and symptomatic if it spontaneously expressessome internal state); and if its relationship to its referent is arbitrary, it is a symbol.

SignalsAll signs can act as signals when they trigger a specific action on the part of thereceiver, as do traffic lights, words in human language such as the race starters Go!or the warning calls of birds. Typically, a signal releases more energy in the receiverthan it takes for the transmitter to send it. For example, the simple release of a mat-ing pheromone into the wind by a female moth (a symptomatic sign and also a sig-nal) can cause the male to fly as much as six kilometers in search of her. Signals arevery common in animal communication, but only a limited subset of human lin-guistic activity consists of signaling.

2.3 Sign StructureNo matter what their type, signs show different kinds of structure. A basic distinc-tion is made between graded and discrete sign structure.

Graded SignsGraded signs convey their meaning by changes in degree. A good example of a gra-dation in communication is voice volume. The more you want to be heard, the louderyou speak along an increasing scale of loudness. There are no steps or jumps from onelevel to the next that can be associated with a specific change in meaning.

Gradation is common in many forms of communication. The hands of mostclocks move (or appear to move) in a graded manner, as does the needle of an auto-mobile speedometer. Many animal signs, such as the barking of dogs, are graded aswell. A goose has essentially one type of honk, which may become louder and fasteras it takes off in flight, but does not become another kind of honking. The graduallyincreasing fear in the facial expression of the monkey depicted in Figure 18.5 is alsoa graded sign.

Discrete SignsDiscrete signs are distinguished from each other by categorical (stepwise) differ-ences. There is no gradual transition from one sign to the next. The words of






Figure 18.6 Some discrete signs: a. odometer; b. traffic lights; c. words of a human language

Figure 18.5 Some graded signs: the facial expressions a, b, and c of the macaque mon-key represent just three points on a continuum expressing fear; a. is a neutral face; b. expresses slight fear; and c. expresses extreme fear. Each expression grades into the next.The hands of the clock in d. express minutes and hours in a graded manner.

Sign Types and StructureAll three types of signsiconic, indexical/symptomatic, and symboliccan be gradedor discrete. A photograph is iconic and discrete, but a threatening canines gradualbaring of its fangs is iconic and graded. Morse code is symbolic and discrete, but aslowly dimming light that signals the beginning of a theatrical performance issymbolic and graded. Symptomatic signs, too, may be discrete (the traffic lightagain) or graded (the crying of a child or the act of blushing).

It is possible for a discrete sign to be internally graded, and even to slip over intoanother type by degrees. Human crying, for example, is interpreted in experiments

human language are good examples of discrete signs. There is no intermediatestage between the words stop and go in English except that which can be expressedby other discrete words or combinations of words, such as start to go. The digitaldisplays of watches are discrete as well, since they progress from one minute (oreven second) to the next with no gradation. Traffic lights, too, are discrete signs;there is no gradual shifting from green to yellow to red (see Figure 18.6).


At the extreme ends of the continuum, there is no difficulty interpreting thesound as one or the other, although it is difficult to say precisely when a sob becomesa scream. Thus we can say that sobbing and screaming are discrete symptomaticsigns, but each of them is internally graded, and their gradations overlap. The sameis true of many vocalizations in animal communication.

2.4 A View of Animal CommunicationTheyre like Swiss watches . . . they just react. Their genes and hormones and experi-

ence tell them what to do. They dont think about it.

ZOOKEEPER BEN BECK (ON GOLDEN LION TAMARIN MONKEYS)

Most animal communication, it is claimed, shows little arbitrariness. It is said to belargely iconic and symptomatic and hence not deliberate or conscious in intent.



Figure 18.7 The graded continuum from sobbing to screaming (the height of the stip-pled and blackened areas represents the audibility of the vocalization and the width itsduration): both sob and scream are discrete signs, even though each grades into the other.

as becoming gradually more like screaming as the audible intake of breath betweensobs becomes shorter and shorter. Figure 18.7 illustrates this phenomenon.


Animal communication is also said to lack symbols in its sign repertory. For exam-ple, if a monkey gives a certain cry in the presence of danger, it is assumed that themonkey is spontaneously signaling its fear by vocalizing, but is not deliberatelywarning other group members of the danger. The symptomatic vocalization, whichis a nonarbitrary symptom of the animals internal state, is interpreted and used byother members of a troop for their own benefit.

It follows from this view of animal communication that the acquisition of com-municative systems by animals was in the past assumed to be largely devoid of learn-ing and experience. Rather, it was claimed that the systems are rather strictly limitedby genetic inheritance, and in this sense are radically unlike human language, theacquisition of which requires exposure to a mature system. This limitation certainlyappears to be true in some cases. When raised in isolation, animals as diverse as thefox, the elephant seal, the cat, and certain monkeys develop the full range of vocal-izations typical of their species. However, as we will see in Section 4 of this chapter, thesituation can be more complex than this.

It is also claimed that animal communication is neither conscious nor deliber-ate. It is not widely believed, for example, that a monkey assesses a situation andthen deliberately chooses to warn group members of danger by selecting a sign froma repertoire of meaningful sound symbols at its disposal. For this reason, the termstimulus-bound is also used to describe animal communication, since it is oftenclaimed that animal communication only occurs when it is triggered by exposure toa certain stimulus or for certain specific ends. Animals do not communicate aboutanything but the here and now. As the philosopher Bertrand Russell once noted, Nomatter how eloquently a dog may bark, it cannot tell you that its parents were poorbut honest.

With respect to structure, animal communication is said to show few traces ofdiscrete structuring beyond the obvious fact that one group of symptomatic,graded signals may sound very different from another. Whining in dogs, for exam-ple, is clearly different from barking, but both are assumed to be symptomatic, andthe two may grade into each other. Combining and recombining of discrete unitsof structure such as phonemes, morphemes, and words is not characteristic of theway animals communicate. Dogs do not combine whines and barks to producenovel messages.

This does not mean that animal communication consists of random emotionaloutbursts. Nor does it mean that animal communication does not show structure.Animal communication is both complex and organized. Evolutionary pressure hasguaranteed that animal communication is optimally in tune with the survivalrequirements of each species. The electrical communication of Amazonian eels is anexcellent means of communication in muddy waters. The danger whistle of a small,tree-dwelling primate like the galago is ideal for nocturnal communication in a denseforest. Small jungle frogs in South America communicate by sticking out their longand colorful legs, ideal for sending messages in the dim and noisy jungle. But junglefrogs do not try new combinations of leg movements in order to come up with anoriginal message, any more than the electric eel recombines frequencies in order tosignal something it has never conveyed before. Animal communication appears tobe limited in the messages it can convey.




But is animal communication so very unlike human language in every respect?The next sections examine the communication systems of several kinds of animalsand compare them with human language.

3 The BeesI have no doubt that some will attempt to explain the performances of the bees as

the results of reflexes and instincts . . . for my part, I find it difficult to assume that such

perfection and flexibility in behavior can be reached without some kind of mental

processes going on in the small heads of the bees.

AUGUST KROGH, SCIENTIFIC AMERICAN

3.1 The SystemForager bees display a remarkable system of communicating the location of a foodsource to other bees in their hive. When a food source has been discovered, the for-ager flies back to the hive and communicates information about it by performingspecial movements (which humans call dancing) before other members of the hive.The dancing conveys information about the location of the food source, its quality,and its distance from the hive.

DistanceDistance is conveyed by one of three different dances performed on the wall or floorof the hive (some species have only two different dances, and so may be said to havea different dialect). In doing the round dance, the bee circles repeatedly. This indi-cates a food source within five meters or so of the hive. The sickle dance indicates afood source from five to twenty meters from the hive. It is performed by the beedancing a curved figure-eight shape. The tail-wagging dance indicates distances fur-ther than twenty meters. In this dance, the bee wags its abdomen as it moves for-ward, circles to the right back to its starting point, repeats the wagging forwardmotion, and circles left. The cycle then begins again.

DirectionThe round dance does not communicate direction, presumably since the food sourceis so close to the hive. The direction of more distant food sources is indicated in theother two types of dance.

As the bee performs the sickle and tail-wagging dances, it is simultaneously indi-cating the direction of the food source. Bees orient themselves in flight relative to theangle of the sun. When danced on the floor of the hive, the angle of the open side ofthe sickle dances figure eight or the angle of the wagging path during the tail-waggingdance indicates the direction of flight. When the dancing is performed on the verticalwall of the hive, it is apparently understood that the top of the hive wall represents thecurrent position of the sun in the sky. During the sickle dance, the angle of the open




QualityQuality of the food source is indicated by the intensity of the dancing and the num-ber of repetitions of the circling movements. As the food source is depleted, thedance is performed with less vivacity.

Other FactorsThese messages are not communicated with perfect accuracy, nor are they the onlyones involved in bee communication. Bees also leave a hive-specific pheromone traceat the site of the food source, thereby directing their fellow foragers to the preciselocation. The bees also carry back traces of the food source odors, which further aidother bees in the search. A complex of communicative modes operating on differentchannelsa constellationis thus employed in bee communication. This use ofdifferent modalities to communicate the same information is called redundancy.Redundancy helps guarantee that communication will succeed in the event one orthe other modalities fails or is imperfectly transmitted. All communication systemsmake use of redundancy. (Human language is no exception; e.g., the presence of allo-phonic features such as voicelessness and aspiration on syllable-initial voicelessstops, or both the length and quality differences of vowels, provides redundancy thatassists in decoding the signals.)

3.2 Bees and HumansHow does bee communication compare with human language? The three patternsthat the bees dance are not obviously connected with the messages they communi-cate and so are symbolic in nature (though it is possible to argue that relative distance



Figure 18.8 Bee dancing

side of the figure eight relative to the hives vertical alignment indicates the directionof flight toward the food source relative to the sun. When the bee performs the tail-wagging dance, the angle of its wagging path relative to the hives vertical angle indi-cates the path of flight toward the food source relative to the sun. Figure 18.8illustrates the dances and their manner of indicating the direction of the food source.


is iconically represented in that a greater distance covered by the bee in each cycle ofthe dance corresponds to a greater distance of the nectar source from the hive). Thecommunication of direction is indexical when carried out on the hive floor (in thesense that it points in the direction of flight), and in this sense may be comparable toa human gesture. Bees are, however, capable of transforming this information into asymbolic representation, since they transfer the horizontal flight path to a verticalrepresentation on the hive wall. The expression of food-source quality is, in all prob-ability, symptomatic: the more stimulated a bee is by the quality of the food source,the faster it dances.

The total communicative constellation involves other, redundant sources ofcommunication as well, such as pheromones and food-source samples. The perform-ance even involves audience participation. During its dancing, the returning bee isexpected to provide samples from the food source. If it fails to do so, it may be stungto death.

Bee communication, then, like human language, shows symbolic, indexical, andsymptomatic traits, redundancy, and interaction between sender and receiver of themessages. But there is a major difference between the two systems of communica-tion: the topic of bee language is severely constrained. Bees communicate only aboutfood sources. Furthermore, their potential for communication is very limited. Onlycertain locations of food sources can be conveyed. Bees cannot communicate thenotion of up or down. They can be easily tricked into communicating the wrongdirection of the food source if a strong light source is placed in an incorrect positionwith relation to the food source. They can also be tricked into giving the wrong infor-mation about distance to the food source if they are forced to walk or stop severaltimes during their trip. This indicates that they gauge distance by time. The beesshow no means of assessing varying information and communicating this fact. Theirsystem of communication appears to be close-ended and limited to a specific num-ber of facts about a specific type of information.

It also appears that bee language is largely innatethat is, there is very little needfor a new forager bee to be exposed to the system in the presence of other bees.Foragers on their first flight perform the appropriate dances, although they refine theirperformance to some extent with time and exposure to other dancing. Their flight ori-entation to the sun is imperfect at first, but it develops within a few hours.

The innateness of bee dancing has been tested by cross-breeding Austrian bees,which do not perform the sickle dance to express intermediate distance of the foodsource from the hive, with Italian honeybees, which do. The results of such experi-ments further support a genetic interpretation of bee communication. In the cross-breeding experiment, the bees that bore a physical resemblance to their Italian parentperformed the sickle dance to indicate intermediate distance 98 percent of the time.The bees that bore a physical resemblance to their Austrian parent performed theround dance to indicate intermediate distance 96 percent of the time; they did notperform the sickle dance at all. The dance pattern used in a specific situation appearsto be inherited from a certain parent along with other more obvious genetic traits.

In 1948, when the Danish physiologist August Krogh made the statement quotedat the beginning of this section, he struck at the widely accepted notion that animalbehavior was either the result of some kind of conditioning, or, in some ill-definedway, instinctive. Much has been learned since then about the enormous quantity of




information imparted by genetic transfer. It is now possible to state with a fairdegree of certainty that the complex and sophisticated behavior of bees and otherequally remarkable insects is in all probability largely genetically predeterminedand, unlike human language, it relies very little on exposure to the mature systemin order to be acquired.

4 The BirdsHow intelligent is a creature that can amuse himself for 15 minutes by uttering, over and

over, the following sounds: uhr, uhr, uhr, Uhr, URH, URH, Wah, Wah, wah, wah, wah.

JAKE PAGE (ON HIS AMAZON PARROT)

4.1 Bird VocalizationBirds, as Jake Page later found out, can do a lot more than utter sounds over and over.Indeed, research on natural communication among birds has already shed light oncertain parallels in human linguistic communication.

Bird vocalization can be divided into two types, call and song. Calls are typicallyshort bursts of sound or simple patterns of notes. Songs are lengthy, elaborate pat-terns of mostly pitched sounds.

CallsCalls serve very specific functions in the bird community. They typically warn ofpredators, coordinate flocking and flight activity, express aggression, and accom-pany nesting or feeding behavior. The cawing of crows is a typical call. It appearsto convey a generalized mobilization because of possible danger. When a crowhears cawing, it flies up to a tree if it is on the ground, or flies higher in a treeor to another treeif it is already in one. (If there are crows in your neighborhood,you can test this yourself, as cawing is easy to imitate.)

In some birds, individual calls are associated with specific activities; a danger callis quite different from a call given when birds are grouped in flight. The danger callgiven by small birds when larger avian predators threaten them is typically thin andhigh-pitched. This kind of sound is difficult to locate, and so can be given as a warn-ing without revealing the position of the caller. A flight call is generally short, crisp,and easy to locate by other group members. The honking of geese in flight is a typi-cal example of this sort of call. Because it is loud and easy to locate, it is well suitedto enable the bird flock to stay together. Such functional utility is typical of bird calls,and in fact, calls that serve the same communicative purpose are often remarkablysimilar among different species of birds.

SongBirdsong is different from calling. Although calls are produced year-round, singing islargely limited to spring, summer, and autumn. Furthermore, it is generally onlymale birds that sing.




The main purposes of song are, as far as we know, to announce and delimit theterritory of the male and to attract a mate. Birds establish territory for breeding pur-poses and defend it vigorously. Across the United States, it is a common sight in thespring to see a red-winged blackbird (Agelaius phoeniceus) and its mate team up todrive away a male of their species that has strayed into their territory. The use ofsong enables male birds to establish and maintain this territory without constantpatrolling and fighting. Moreover, once a bird has established its territory, its songserves to attract and maintain contact with a mate. It follows that birdsong isunique from species to species, and even varies to some degree from bird to birdwithin the same species, since its purposes require identification both of species andof individuals.

In some species, songs are nothing more than a successive repetition of calls. Inothers, songs consist of complex patterns of pitchessometimes called syllablesthat form longer repeated units or themes. The sometimes elaborate complexity ofsong structure reflects individual variation among the singers, and, as pointed outpreviously, serves a specific purpose. Figure 18.9 shows a spectrogram (an acousticrecording that shows pitch and intensity of sound along a time axis) of the song ofthe European robin (Erithacus rubecula). Note how the different subsections of thesong are distinct and recognizable. There is also some evidence that sections of asong are combined in different orders by certain birds, but there is no evidence thatrecombination is associated with different meanings.



Figure 18.9 Spectrogram of a robin song; pitch is shown vertically along the L-R timeaxis, intensity by greater darkness

Avian DialectsThere is evidence for both song and call dialects among bird species. Researcherseven speak of avian isoglosses (lines drawn on a map to indicate shared characteris-tics among dialects; see Chapter 14, Section 2) that are based on variations in themelody of song syllables or themes (see Figure 18.10). The reason for the existenceof dialects is still unclear; it may be no more than a reflection of individual avianvariation in song and call learning. If it is, we are led to an intriguing issue in the


relationship of bird vocalization to human languagethe question of how birdvocalizations are acquired.

4.2 Birds and HumansThe acquisition of call and song by birds shows interesting parallels with recenthypotheses about the acquisition of language by human children (see Chapter 10).Though a great deal of bird vocalizationparticularly callingappears to be innate,there is much that appears to be acquired. Studies of avian dialects have shown thatbirds reared in the same nest acquire different song dialects when they live in differ-ent dialect areas. It also appears to be the case that singing ability is lateralized in theleft brains of birds, as is linguistic ability in humans. Still more significant for lin-guistic study is the fact that some birds must acquire the species-specific characteris-tics of their song within a certain time span or critical period. A number of birdspecies do not develop fully characteristic songs if they are not exposed to them dur-ing the early stages of their lives.

The chaffinch (Fringilla coelebs) is one such bird. If chaffinches are reared inisolation, they sing, but replicate only in a general way the typical song of thespecies. If young chaffinches are reared away from fully developed singers, butwith other young chaffinches, the entire experimental community develops anidentical song. Finally, chaffinches that have been exposed to only some part ofthe fully developed song (those that are captured in the autumn of the first yearof life) will, the following spring, develop a song that is partially typical but notcompletely well formed.

These experiments indicate that there are some songbirds that have both aninnate and a learned component in their song. The innate component predisposesthem to perform a general song that is extremely simplified. This has been called atemplate or a blueprint. Only exposure to the fully formed song of the species willenable them to produce the correct song. (Exposure to other songs causes some speciesto imitate in this direction; other species simply do not acquire anything they are



Figure 18.10 Avian isoglosses: call patterns of male Hill Mynas (black dots show mynagroups; the shaded area shows forested hills and the unshaded, open plain; the heavier theblack lines, the more song characteristics are shared by the group within its boundaries)


exposed to unless it is their own species-characteristic song.) Finally, it is clear that cer-tain birds do not acquire their characteristic song in a brief span of time, but that sev-eral seasons of exposure are required. The evidence from songbird studies, while nottransferable directly to humans, gives strong support to the idea that a combination ofinnate and acquired components is one way that the acquisition of complex behaviortakes place in nature.



LANGUAGE MATTERS Talking Parrots

In recent years, the linguistic abilities of Grey African Parrots have received con-siderable attention, both in the media and in scientific circles. Although the vocab-ulary of the birds is not especially large (it is in the range of one hundred words)and there is no evidence of an actual grammar, two facts are of great interest.

The first has to do with the way in which parrots acquire their vocabulary. Inthe studies involving Alex, the best known of the talking parrots, two techniqueshave proven successful: simple exposure to the words in appropriate sentences(Would you like some corn? Corn tastes yummy.) and a procedure in which thetrainer teaches the word to another human and rewards him or her for a cor-rect answer as the parrot looks on.

Second, Alex and other parrots in the same laboratory have manifested anability to use their vocabulary to answer quite intricate questions about color,size, and number. For instance, when shown a small green key and a large redkey, Alex could respond correctly to questions such as, What toy? (key), Howmany? (two), Whats different? (color), What color [is] smaller? (green),and so forth.

To find out more, see Irene Pepperberg, The Alex Studies (Cambridge, MA:Harvard University Press, 1999) and www.alexfoundation.org/irene.htm.

5 Nonhuman PrimatesSome animals share qualities of both man and the four-footed beasts, for example, the

ape, the monkey, and the baboon.

ARISTOTLE, ON ANIMALS

Fascination with nonhuman primates goes far back in human history. Their socialbehavior has long been seen as an amusing (and sometimes instructive) parody ofhuman behavior. Since the recent establishment of the fact that we are closelyrelated genetically to these animalssome 99 percent of our genetic matter is sharedwith chimpanzees and gorillasthe resemblance of their behavioral, social, andcommunicative traits to ours has been seen as more than a droll counterpart to humanactivity. For some linguists, the question of our shared cognitive, and especially




Figure 18.11 The primates

linguistic, ability has become more important; it is thought that a better under-standing of nonhuman primates may shed light on the evolution of human socialand cognitive abilities.

Primates form a large class of mammals, which range from the tiny tarsier to theimposing mountain gorilla. Among the nonhuman primates, some are nocturnal, somediurnal in their activity cycle. Some are solitary, some form part of complex socialgroups. Many are tree-dwelling, and many are ground-dwelling. Some are quadrupeds,and some show periods of bipedal locomotion. Figure 18.11 shows one widely acceptedclassification of the primates.

The prosimians are an evolutionarily early group found on the island ofMadagascar, in sub-Saharan Africa, and in Southeast Asia. New World Monkeysrange from Mexico through South America. Among them are the only primateswith prehensile (grasping) tails. Old World Monkeys include the many tree- andground-dwelling species of Africa and the Far East. The larger nonhumanprimatesbaboons, chimpanzees, and gorillasare not native to North and SouthAmerica. Baboonslarge, mainly ground-dwelling primatesare found from cen-tral to northern Africa. They show a high degree of social organization, intelligence,and aggressiveness. The hominoids include the agile gibbons, solitary orangutans(both found only in Southeast Asia), the large but peaceful gorillas, the chim-panzees, and humans.


In Section 5.1, we first turn our attention to nonhuman primate communicationin the wild. It is there that we can gain an initial understanding of how forms of non-human primate communication resemble or differ from our own in terms of func-tion and structure.

5.1 Some Functions of Nonhuman Primate CommunicationThe validity of studies of communication among captive primates has been criticizedbecause the animals social existence is highly limited and compromised in zoos.Studies of nonhuman primate communication have largely left the zoo and labora-tory and moved into the animals natural habitat. While careful observation of non-human primate communication is still the basis of this work, the use of playbackexperiments, in which tape recordings of natural calls are played back over hiddenloudspeakers, has led to a greater understanding of the communicative systems ofthese animals.

Although the social life of even the most gregarious nonhuman primate is rel-atively simple when compared to that of humans, primates, like humans, commu-nicate for many different reasons. Typical nonhuman primate communicationserves to mark and announce territory, to warn other group members of danger, toseek or maintain contact with a mate or other members of the species, and to inter-act with members of the troop or species in various ways we can call socializing.Socializing vocalizations are particularly important in mother-child bonding and inprimate groups with a complex and hierarchical social structure. In these groups, itis important to know which members have a higher or lower rank so that groupmembers can behave accordingly in their presence. Vocalization is a key factor inmaintaining this behavior.

As we briefly survey some aspects of the structure of nonhuman primate com-municative systems, we will also refer to the ways in which structure and function arelinked.

5.2 Prosimian CommunicationProsimian communication shows a small repertoire of sounds that are patterned intodiscrete groups. The lemur (Lemur catta) of Madagascar is a typical prosimian withrespect to its vocal communication system. It has been described as making essentiallytwo types of vocalizationnoises and callseach of which shows some grading.The vocalizations appear to be symptomatic. They are classified in Table 18.1; quasi-phonetic descriptions like spat should be interpreted as onomatopoeic.

Each graded set of sounds is used in a circumscribed range of situations. Thecalls, in particular, are limited to threat or fear encounters. They seem to form agraded series, ranging from the light spat to the bark in intensity. A small repertoireof distinct vocalizations is the norm among prosimians. The slow loris (Nycticebuscoucang), an Asian prosimian, is reported to have no more than five calls.




5.3 MonkeysThe study of communication among the many varieties of New and Old WorldMonkeys is too vast for this chapter. An oversimplified picture reflects what mostresearchers agree is primarily a symptomatic system, but one that shows a largernumber of signs, with more gradation among them, than does the communicationof prosimians.

One study of the Bonnet macaque (Macaca radiata), a South Asian monkey,presents a system of twenty-five different basic patterns that are used in varioussocial interactions, including contact, agonistic encounters, foraging, greeting, sex-ual contact, and alarm giving. These vocalizations are determined by correlatingobservation with spectrographic analysis; descriptive labels are also given to thevocalizations, such as whoo, rattle, growl, whistle, and bark. These basic patterns aredescribed as grading into each other. It is also claimed that they occur in combina-tions. There is no evidence, however, that these recombinations mean anythingnovel when they occur.

The communication systems of many monkeys appear to be genetically deter-mined. This has been established by raising newborns in isolation. However, thisstatement cannot be made for all monkeys. For some monkeys, input from the adultsystem appears to be required.

The study of one small monkey has suggested that not all monkey vocalizationsare symptomatic, and that experience and learning can play a role in the acquisitionof the communicative system. The East African vervet monkey (Cercopithecusaethiops) is said to have three distinctive and arbitrary calls that announce the pres-ence of eagles, snakes, or large terrestial mammals posing a threat. These calls areassociated with different responses by the monkeys. When they hear the eagle call,the monkeys look up or run into the bushes. The snake call causes them to lookdown at the ground near them. The mammal alarm sees them run up into the trees,or climb higher in a tree if they are already in one.

These findings, which appear to have been well established by playback experi-ments since they were first reported in 1967, suggest that not all nonhuman primatesrely strictly on symptomatic signals to communicate or to trigger behavior in others. It



Noises Calls

Sound Context Sound ContextSingle click In response to Light spat (yip) When driving off

strange objects threatening inferiors

Clicks, grunts During locomotion, or Spat When crowded orfor friendly greeting handled roughly

Purr While grooming Bark When startled

Table 18.1 Lemur vocalization


is claimed rather that the vervets assess the potential danger situation and then choosea specific call with a clearly defined referent to announce the danger. Furthermore, eachcall is a vocalization signifier that is arbitrarily linked with its referent. Other monkeysrespond appropriately to the calls without necessarily observing the danger themselves.All this taken together suggests a cognitive ability for classification of objects in theworld and an ability to link this classification system to arbitrary sounds for purposesof intentional communication.

The vervet may not be an isolated case. Goeldis Monkey (Callimico goeldii ), foundin South America, is said to have five different alarm calls, three of which are usedwhen terrestrial predators approach, and two of which have been heard in the pres-ence of large birds. Such observations support the claim that certain monkeys havethe cognitive capacity to associate perceptual categories with vocalizations.

The acquisition of these signals among vervets is interesting. Infant vervetsappear to distinguish innately among broad classes of mammals, snakes, and birds,but they also give the eagle call when other birds appear and the leopard call whenother terrestrial mammals appear. Adults distinguish between leopards and less dan-gerous mammals, and eagles and less dangerous birds (as well as between snakes andsticks), and it is claimed that this ability must be perfected through experience. Thisonce again suggests that a mixture of innate components and learning is typical ofthe way some communication systems are naturally acquired.

5.4 Gibbons, Orangutans, and ChimpanzeesSince the higher primates are close genetic relatives of humans, it is natural to expecttheir vocal communication to resemble that of humans. Perhaps surprisingly, commu-nication among the higher primates does not show much indication of discrete vocalsigns that could be interpreted as resembling human words. For the most part, the com-munication systems of these animals are made up of groups of graded vocal signs, someof which appear to display a certain level of sign-symbol correspondence.

Gibbons and OrangutansGibbons display an interesting form of vocal interaction known as duetting. Thisis the interchange of calls in a patterned manner between two members of aspecies, and is found among certain birds, bats, and even antelopes. Duetting is,however, atypical of primate communicationamong the hominoids, only gibbons perform it. Recent playback experiments show that duetting among gib-bons serves to maintain spacing among territories much as does birdsong (seeSection 4.1). Playback of duetting within a gibbons territory will cause it toapproach the apparent source of the vocalizations, possibly with the intent of driving the intruders out. Playback of singing and duetting from outside a groupsterritory only infrequently evokes a response. Recognition of individuals does notappear to play a role in these vocalizations.

Unlike gibbons, which live in family groups, orangutans largely keep to them-selves (except for mother-child pairs). Some sixteen distinct vocalizations have beenidentified, many of them straightforwardly symptomatic. Among the solitary forestmales, loud calls up to three minutes long serve a territorial and spacing function.




These calls also identify the individuals who produce them. High-ranking malesapproach calls, presumably to confront the intruder, while low-ranking males stayaway from areas where they hear the calls of high-ranking males. These calls are, inother words, indexes that stand in for the individual animals themselves, and orang-utans must identify and assess each of these calls before acting on them.

ChimpanzeesChimpanzees vocalize with a number of graded calls. As many as thirty-four distinctcalls have been reported for one species (Pan troglodytes). Some of these appear toshow rather specific referents. Chimps typically produce a vocalization called roughgrunting in the presence of a favorite food source. A more powerful vocalizationknown as a pant-hoot (a sound that carries well in dense forest) often indicateslocation. Pant-hooting is also used in greeting or when chimps are excited aboutsomething. A third vocalization, pant-grunting, appears to be used by lower-rankinganimals in the presence of higher-ranking ones, apparently acknowledging a subordinate status in a social hierarchy. Recent work suggests that the pant-hoots ofa band of Ugandan chimpanzees in the wild may be composed of several acousticdiscrete subtypesa graded continuum (see Section 2.3). This study also suggestedthat there is some association of vocalization and particular behavioral and socialcontexts (travel, feeding, resting, etc.).

Language in the Wild?Especially among highly socialized species, nonhuman primate vocalizations allshow a great deal of variation. There is every indication that their vocalizations formpart of a constellation of redundant communicative acts including gesture, posture,gaze (eye pointing), and the expression of affect, all of which must be interpretedby other troop members. The obvious complexity of communication systems amongthese animals suggests that the level of mental activity devoted to communicativebehavior is sophisticated and well developed.

But despite the high degree of intelligence and social organization these animalsdemonstrate, there is not a great deal of evidence for arbitrary relationships betweensound and meaning among apes. Even more significantly, there is no evidence ofrecombining various sections of a message to form new messages. Nothing that par-allels the phonemic or morphological recombination of human language has beendiscovered in the natural communication systems of nonhuman primates.

It is possible that the lack of parallels with human linguistic communicationin species closely related to our own may be because of the nature of their socialorganization. The small groups or family units typical of chimpanzees and gorillasliving in a food-rich environment may not have required the development of anyother mode of communication. What has evolved is suited to their needs. This doesnot mean, however, that our near-relatives do not possess any of the cognitive abil-ities necessary for using a system of communication akin to human language.There is some evidence, for example, of left hemisphere development of the typeassociated with human linguistic ability. A number of recent experiments withnonhuman primates have attempted to determine the extentif anyof their lin-guistic abilities.




6 Testing Nonhuman Primatesfor Linguistic AbilityMuch attention has been paid in recent years to nonhuman primates that commu-nicate with humans through the use of sign language.

Controlled testing of the possible shared linguistic abilities of nonhuman pri-mates and humans goes back to 1948, when two psychologists attempted to trainViki, a young chimpanzee, to say meaningful words in English. With great effort,Viki learned to approximate the pronunciations of a few words like cup and papaover a period of fourteen months. Unfortunately, the experiment was doomed tofailure from the start, since the vocal fold structure and supralaryngeal anatomy ofthe chimpanzee are unsuited for producing human sounds.

Chimpanzee vocal folds are fatty and less muscular than those of humans, andthe neurological pathways between the brain and vocal folds are less developed thanin humans. The chimpanzees epiglottis extends well up into the throat cavity, whichlessens the range of sounds it can produce. Finally, the whole larynx-tongue linkagerests higher in the chimpanzee throat than in humans, which results in limitationson its humanlike sound production as well. In short, chimpanzee anatomy isunsuited for human speech, and concentrating effort on teaching one to articulatewords was distracting from the more provocative question: To what extent is thechimp mentally capable of linguistic behavior?

6.1 Some ExperimentsAn experiment conducted from 1965 to 1972 by Allen and Beatrice Gardner with ayoung female chimpanzee named Washoe created a new perspective on nonhumanprimate linguistic abilities. The Gardners attempted to raise Washoe much as ahuman child would be raised, and to teach her American Sign Language (ASL), on theassumption that it was a genuinely linguistic form of communication (of whichthere is no doubt). Given the known manual dexterity of chimpanzees, it was feltthat sign language might provide a window on chimpanzee linguistic abilities.

WashoeThe Gardners reports claim that Washoe communicated intentionally with arbitrarysigns in a creative manner, and thus showed the rudiments of human linguistic abil-ity. Washoe learned to produce approximately 130 signs over a period of three years,and she recognized many more. Most significantly, it is claimed that Washoe spon-taneously combined these signs to form novel utterances. She is reported to havesigned WATER BIRD (in this chapter, signs are indicated by capital letters) on seeingducks. Washoe also is said to have spontaneously produced BABY IN MY CUP whenher toy doll was placed in her drinking cup and she was asked WHAT THAT?

Washoe, who passed away in 2007 at age forty-two, was the first but not the onlychimpanzee to be taught sign language. The results have suggested to some linguiststhat chimpanzees show greater ability to associate arbitrary tokens with referents thanwas believed earlier, and that they demonstrate rudimentary syntactic behavior. Other




chimps, gorillas, and an orangutan that have been taught elements of ASL since thepioneering Washoe experiment are reported to have performed even better.

NimStill other experiments in teaching chimpanzees sign language have produced con-tradictory results. The achievements of a chimpanzee named Nim have been inter-preted by his teachers as consisting of frequent repetitions of a small number ofall-purpose signs (NIM, ME, YOU, EAT, DRINK, MORE, and GIVE) that were largelyappropriate to any context. These signs are said to have made up almost 50 percentof Nims production. Furthermore, there are no reports of his engaging in creativecombining of signs.

6.2 Nonsigning ExperimentsMuch of the criticism leveled at Washoes performance centered on the relative infor-mality of her training and claims at the time that ASL is a loose communicative sys-tem that does not require a strict adherence to syntactic rules (though we now knowASL to be a rule-governed natural language). Two very different experiments withchimpanzees attempted to forestall such criticism.

LanaA chimpanzee called Lana was trained to fulfill her needs for food, fresh air, grooming,and entertainment (in the form of slide shows) by requesting these from a computer-controlled apparatus. Communication with the computer was carried out by meansof a simple rule-governed language of nine arbitrary symbols. The symbols were onbuttons that lit up and activated the computer when pressed. Any deviation from thesyntactic rule system invented for the experiment failed to get the desired responsesfrom the computer. Human experimenters communicated directly with the chim-panzee through use of the same symbols. Lana learned to label and request food andother amenities through the computer. The experiment with Lana was criticizedbecause she was said to have learned simple reflex associations among symbol,sequence, and reward. There was no evidence that she had acquired the roles under-lying the sequences, and so could not be said to have displayed linguistic abilities.

SarahAnother well-known experiment involved training a young female chimp namedSarah to manipulate arbitrary plastic symbols in a predetermined manner in order toobtain rewards. Sarah had to learn to use word order correctly, since only the ordershown in Figure 18.12 would obtain a banana.



Figure 18.12 Arbitrary symbols used in experiments with the chimpanzee Sarah


She also seemed to show sensitivity to more abstract words like if/then in sentenceslike those shown in Figure 18.13. But was Sarah learning aspects of human language orwas she, too, trained? Humans who are taught similar skills perform them as well asSarah but find it difficult to translate them into human language. They approach theexercise of moving plastic symbols around to obtain a reward as a puzzle that is not nec-essarily associated with language. It has been suggested that Sarah was performing thesame kind of puzzle-solving and not demonstrating humanlike linguistic capacities.



Figure 18.13 A sentence understood by Sarah

LANGUAGE MATTERS The Pro-Primate Perspective

The most widely known of the signing primates is the gorilla Koko, whose accom-plishments have been documented by Penny Patterson of the Gorilla Foundation(www.koko.org/index.php). Other useful sources of information include theChimpanzee and Human Communication Institute at Central WashingtonUniversity (www.cwu.edu/~cwuchci/) and the Language Research Center atGeorgia State University (www2.gsu.edu/~wwwlrc/).

Interest in human-animal communications is not new. Language-using dogs,cats, pigs, and even turtles have been reported for thousands of years. The basis ofmuch of the current criticism of these ancient reports and contemporary experimentsrests on the performance of a horse in Germany at the turn of the twentieth century.

6.3 The Clever Hans ControversyWhen I play with my cat, who is to say that my cat is not playing with me?

MICHEL DE MONTAIGNE, ESSAYS

In 1904, a Berlin school teacher named Wilhelm von Osten claimed to possess ahorse that showed evidence of a humanlike capacity to think. His horse, Clever


Hans (der kluge Hans), could supposedly calculate and convey messages by tappingout numbers or numbered letters of the alphabet with a front hoof or by noddingits head.

Experimentation by a skeptical scientist, Oskar Pfungst, eventually showed thatClever Hans was not so much a creative thinker as a careful observer: the horse per-ceived cues that indicated that he had performed correctly. For example, von Osteninvoluntarily moved his head very slightly when a correct answer had been reached.This movement (less than five millimeters) was outside the normal perceptual rangeof human observers, but the horse had learned to associate it with the correct answer.When observers did not know the answer to a question, or when Clever Hans wasblindfolded, he failed to perform his miracles.

Clever Hanss performance resulted from dressage, a type of interactionbetween trainer and animal that depends on the animals interpreting subtle cuesgiven by the trainer. The Clever Hans phenomenon is an excellent example of dres-sage, which need not involve conscious communication on the part of humans. Thehighly developed perceptual ability displayed by Clever Hans is common to manyanimals. Many scientists believe that chimpanzees and gorillas that use sign lan-guage and perform other language-like tasks are demonstrating nothing more thanthe Clever Hans phenomenon.

The idea is as follows. Human trainers want very much for their animal chargesto succeed. This desire is translated into involuntary actions, which can be seized onby the animal because of its keen perceptual abilities; it is these cues that determinethe animals performance. A typical example of this is pointed out in Washoessigning of BABY IN MY CUP, which has been recorded on film (First Signs of Washoe).A careful examination of this interchange shows that the human repeatedly holdsout the object to be signed and then points rapidly at the cup. Probably none of thiscueing was intentional on the humans part.

Some so-called linguistic activity may be the result of factors other than theClever Hans effect. Some reports of creative signing, such as Washoes WATERBIRD, are dismissed as reflex signing that shows no intention of forming combi-nations on the part of the chimp. Reports of the gorilla Kokos displays of wit (sheoccasionally produces the opposite sign of the one requested, such as UP forDOWN) are also considered to be exaggerated or simply wishful thinking byresearchers.

Some reports of linguistic behavior are attributed to nonsystematic or inaccu-rate observing. (For example, if Washoe answered WHAT THAT? with any nounsign, the answer was considered correct.) Other reports are attributed to overopti-mistic interpretation of signs. (The gorilla Koko is reported to intentionally pro-duce rhyming signsthose that are very similar to the ones asked for orexpected.) In short, those who do not view chimpanzee signing and symbol manip-ulation as linguistically relevant claim that this behavior is more simply explainedas arising from straightforward response-reward association and/or from dressage,and not a reflection of linguistic competence. As one researcher noted, training twopigeons to bat a ping-pong ball across a net does not mean that the birds know therules of ping-pong.




6.4 The Great Ape DebateWe believe that . . . there is no basis to conclude that signing apes acquired linguistic skills.

MARK S. SEIDENBERG AND LAURA PETITTO

When these projects [Washoe, Lana, Sarah, and Nim] are taken together, it can be seen

that chimpanzees are within the range of language behavior of humans and therefore

have the capacity for language.

ROGER FOUTS

Researchers involved with the chimpanzees and gorillas that are being taught to signattest to the emotional bonds they form with them, and also emphasize that in usinghuman language, such bonds are a prerequisite to normal communication. Theystrongly insist that apes communicate spontaneously and creatively with humans.Roger Fouts, who has spent many years in close contact with Washoe and otherchimpanzees, puts the case this way.

I reject the notion that there is some ultimate cut-and-dried criterion that distinguishes

language from all other social and cognitive behaviors, or that distinguishes human

communication and thought from that of all other species.

It is important to emphasize that most researchers sympathetic to the idea that apesshow human linguistic abilities employ a broader definition of language than manyof their critics. For these researchers, language use includes socialization and the useof communicative constellations.

For many linguists critical of these projects, a definition of language that rests on itssocial or functional aspects is unacceptable. In much current linguistic thinking, lan-guage is viewed as independent of the purposes it serves. This view, sometimes calledthe linguistic autonomy hypothesis, equates language with grammarthe mental sys-tem that allows human beings to form and interpret the sounds, words, and sentencesof their language, to quote from Chapter 1 of this textbook. It follows from this defi-nition that linguistic ability in nonhuman primates can only be claimed to exist if theanimals produce, at the very least, spontaneous and intentional symbolic signs that aremanipulated in a rule-governed manner.

Symbol UseAll researchers who support the claim that nonhuman primates can employ intentionalsymbolic communication deny that cueing is a major factor in the apes abilities,although most admit that it might be present on occasion. In order to refute charges ofthe Clever Hans effect, researchers employ a strict form of experimentation.

Primate sign language researchers try to avoid cueing by using the double-blindtest. In this test, first a researcher shows the ape objects or pictures of objects that areinvisible to a second human researcher. The apes signing is then recorded by the second researcher and the record is interpreted by a third researcher who has notseen the signing. In this way, unintentional cueing is said to be avoided.




Critics of this research claim that even double-blind tests can be affected byhuman-animal interaction. First, the apes must be taught to perform the task. Duringthis process they may be conditioned to provide certain responses. Secondly, it is dif-ficult to avoid any human-animal interaction during these tests, and this could lead tosubliminal cueing. As we have also seen, many claims for symbolic behavior on anyapes part have been dismissed as stimulus-response conditioningthe mere apeingof behavior in order to obtain a reward. We still have no way of knowing whetherWashoes use of a sign sequence like TIME-EAT indicates that she has a concept of time.

Ongoing work with two chimpanzees named Sherman and Austin has led to theirexchanging signed information about classes of objects such as tool and food. Theseexperiments are claimed to have circumvented any reliance on the Clever Hans effectand shown that signing apes can communicate about whole referential classes of itemsrather than be bound to simple stimulus-response associations with individual itemssuch as banana and ice cream.

Careful control of experiments has convinced some linguists that limited sym-bol use has been exhibited by some apes, perhaps even up to the level of a two-year-old human child. But some linguists who allow that a level of symbolic signing hasbeen achieved have also denied this is a critical feature for defining language. Rather,rule-governed, creative symbol combinations and syntactic behavior are said to bethe critical features.

Creative Signing?A feature of language that sets it apart from most animal communication is itscreativitythe fact that humans can use language to create novel messages. Signresearchers claim that such creativity is present in the many instances of novel com-binations signed by the animals.

An early and famous instance of alleged creative signing was Washoes WATERBIRD (referred to in Section 6.1), which she signed on seeing a duck in the waterfor the first time. Such alleged compound signing behavior has been noted in var-ious signing apes. Some of the gorilla Kokos novel combinations are provided inTable 18.2.



Compound Referent

Milk Candy rich tapioca puddingFruit Lollipop frozen bananaPick Face tweezersBlanket White Cold rabbit-fur capeNose Fake maskPotato Apple Fruit pineapple

Table 18.2 Some sign combinations produced by Koko

Critics say either that such combinations are accidental or that the ape producesthe two signs independently of each other and thus does not display true com-pounding. There is no doubt that Washoe signed both WATER in the presence of


water, and BIRD in the presence of the bird, but there is no consistent indicationfrom her other output that she has a rule of compound formation.

It has been claimed that in more recent and carefully controlled experimentswith a pygmy chimpanzee (Pan pansicus) named Kanzi, statistically significant dif-ferences in the spontaneous ordering of symbols has been observed. The conclusionthat has been drawn from this is that Kanzi has exhibited a form of grammatical rule.For example, Kanzi frequently used combinations of signs that link two actions, suchas CHASE HIDE, TICKLE SLAP, and GRAB SLAP. In fifty-four out of eighty-four cases,the first sign corresponded to the invitation to play and the second to the type ofplay requested.

Is There Syntax?Claims for syntactic behavior among signing apes have also been made. Even thoughit has been claimed that the general (though flexible) syntax of ASL is copied by theapes, reports on the signing chimp Nim (Section 6.1) showed that the animal had noconsistent word order patterning. In fact, Nims syntactic output was structurallyincoherent. His longest sentence is reported as GIVE ORANGE ME GIVE EATORANGE ME EAT ORANGE GIVE ME EAT ORANGE GIVE ME YOU.

Koko the gorilla is said to have developed her own word order in noun phrasesthe adjective consistently follows the noun it modifies. It is difficult to prove claimsfor syntactic behavior in animal signing, because (all) signing forms constellationswith facial expression and gestures and so may be said to reduce the need for rigoroussyntax. Koko, for example, can sign a meaning like I love Coca-Cola by hugging her-self (the sign for love) while signing Coca-Cola at the same time with her hands.

In spite of what is now widely considered to be the disappointment of the earlierstudies (possibly because they expected too much), some controlled experimentationcontinues. Recently, the pygmy chimpanzee Kanzi is reported to have produced sig-nificant (though not wholly consistent) differences in the placement of animateagents in sign combinations. When another chimpanzee named Matata was grabbed,Kanzi produced GRAB MATATA, but when Matata performed an action such as biting,Kanzi produced MATATA BITE.

Lingering DoubtsAs we have seen, supporters of language use among apes have not yet proved tothe satisfaction of all their critics that genuine symbolic behavior is occurring,much less anything resembling rule-governed creativity in compounding or syn-tactic patterning.

Researchers who see the results of ape studies as positive evidence for linguisticability in these animals claim that their opponents keep raising the stakes every timea chimp or a gorilla accomplishes something that could be interpreted as linguisticbehavior. Possible evidence of symbol use or creative signing to indicate linguisticability is dismissed by these opponents as unsurprising or irrelevant. Supporters ofape studies note that their critics are motivated by a long tradition of viewing animals as organic machines that are locked into specific behavioral and commu-nicative repertoires by their genetic inheritance, and that can therefore only respondautomatically to a given situation with a narrow range of signs. Their own view, they




claim, is at once more ancient and more modern in granting animals a certain as yetunknown degree of intentionality and cognitive ability in their behavior.

In general, recent experiments have established more convincingly than earlierape studies that symbol use and referential behavior form part of the cognitivemakeup of some nonhuman primates. Taken together with naturalistic studies, theyhelp circumvent the claim that all evidence of symbol use among nonhuman pri-mates is caused by the Clever Hans phenomenon.

Nonetheless, questions about creative sign combination and syntactic use stillremain. Kanzis alleged rules have been equated with those of a two-year-old child. Butthe major difference between a chimpanzee and a child at that point in their lives is thatthe elementary grammar of a two-year-old is the first hint of a full system that is rapidlydeveloping and that will be in place in a matter of a few more years. While Kanzis com-municative behavior constitutes interesting evidence for a chimpanzees awareness ofthe world, it does not unequivocally imply a system of grammar. It has been noted, forexample, that Kanzis rules are often bound up with a natural order of action or rela-tionships (as when the sign GRAB precedes the sign SLAP).

To critics of these experiments, the apparent lack of rule-governed behavioramong signing apes (especially in the realm of syntax) remains the linguistic hurdlethat the animals have not overcome. It is certain that apes do not show syntacticbehavior to any degree that humans do (e.g., embedding is completely lacking) andmany linguists claim that without such behavior, the apes cannot be said to be usinglanguage. Syntax, in the strict linguistic sense, provides a system of rules capable ofproducing a sentence of potentially infinite length (even though in practice this isnever required). There is no evidence that primates have shown this ability.

Critics of the ape studies have at this time carried the day. Many funding sourcesfor comparative ape-human research have dried up, and most of the subjects havelost their privileged relationships with humans and been returned to zoos. But thesevere reaction to the apparent failure of ape-human linguistic communicationresearch has had positive effects on the field as well. Recent trendsthe number ofexperiments on animal cognition in the wild, and the more carefully controlledexperiments with apes like Kanziare leading us slowly closer to new evidence thatbears on this age-old issue.

6.5 ImplicationsThe real significance of these experiments in ape-human linguistic communicationgoes far beyond popular enthusiasm about what an ape might say to us if it couldtalk. It has often been pointed out that an animals view of the world must be quiteunlike our own. It is perhaps not surprising that apes appear to communicate largelyabout their fundamental emotions and such basic needs as food and play.

It is certain that animals have communication systems that are as rich, sophisti-cated, and subtle as anything found in human language. But are they equivalent tohuman language? We have seen that animal communication and human language sharea number of characteristics, but the greatest difference we have encountered is a funda-mental one: human language is an open-ended system of symbolic signs that can bemanipulated in various ways to express novel output. Animal communication appearsto be built out of rather closed systems that depend very little on symbolic signs but




rather emphasize the interpretation of symptomatic signs. However, this fact does notmake animal communication simple. Symptomatic signs are complex and subtle, andinterpreting them requires a great deal of attention and ability on the part of the receiverto decode and interpret the sign within the communicative context. The wider the rangeof symptomatic nuance conveyed by the sender, the more interpretive power is requiredby the receiver. Animal communicationespecially as we reach the realm of moreexpressive creatures such as mammalsputs a great load on the cognitive power of thereceiver of messages.

Humans, meanwhile, have evolved linguistically to place the burden of theirspoken communication on abstract symbolic signs that require significant cognitiveresources to organize into grammatical utterances. Symptomatic signs are marginal-ized within human grammar, or, more accurately, form the skeleton of the symboliccommunication message; the symbolized messages overlay a subtle pattern of symp-tomatic information such as intonation, stress, accent, and voice quality.

As we have seen, many linguists claim that there is no connection between thecommunicative behavior of nonhuman primates and the complex structures ofhuman language. The opposing view claims that even the capacity for true gram-matical activity can be found in nonhuman primates. This implies that what we call language reflects a cognitive difference in degree and not in kind between humansand these animals. The optimistic view is that such research may ultimately shedlight on the evolutionary origins of our species and its language use by demon-strating the degree of shared cognitive abilities between ourselves and our nearestgenetic relatives.



LANGUAGE MATTERS A Changing Tide?

Although linguists have long been highly skeptical about the relevance of animalcommunication research to the study of human language, there has recently beena shift of opinion of sorts and the possibility of a meaningful connection is nowbeing seriously debated. Particularly influential in this regard was a paper coau-thored by the linguist Noam Chomsky and two psychologists with an interest inthe evolution of communication (Marc Hauser and Tecumseh Fitch). The paperargues that most of the perceptual and conceptual mechanisms involved inhuman language are found in some form in animal systems of communication. Ifthis is right, then the gap between language and animal communication may infact be less abrupt than previously thought, perhaps coming down to recursion(see the beginning of Chapter 5). There is no consensus on this subject, however,and a great deal of additional debate and research will no doubt be needed beforethe matter can be resolved.

For more reading:

Hauser, Marc. 1996. The Evolution of Communication. Cambridge, MA: MIT Press.

Hauser, Marc, Noam Chomsky, and W. Tecumseh Fitch. 2002. The Faculty of Language:What Is It, Who Has It, and How Did It Evolve? Science 298: 156979.

A debate with critics of the new view appears in numbers 95 and 97 of the journal Cognition(2005).


7 Comparing Communication Systems:Design FeaturesThroughout this chapter, we have emphasized the distinction between communica-tion and language. In this final section, we will compare human linguistic commu-nication with what we have learned about systems of animal communication.

7.1 The FeaturesDifferences and similarities between human language and natural animal communi-cation systems can be highlighted by comparing essential characteristics of the sys-tems. These characteristics are called design features, and are set up (perhaps unfairly)with reference to human language. Since this book emphasizes the essentially mentalnature of linguistic ability, the design features that follow do not include the tradi-tional reference to vocal-auditory transmission. What is emphasized is the nature ofthe semantic and organizational structuring of each system. These design features rep-resent an adaptation of work by Charles Hockett and W.H. Thorpe.

1. Interchangeability All members of the species can both send and receive messages.

This is obviously true of human language. It is not the case with bee dancing (performed only by foragers) or birdsong (performed only by males). Nonhuman primate vocalizations appear to be largely interchangeable.

2. Feedback Users of the system are aware of what they are transmitting.

Humans monitor their linguistic output and correct it. It is debatable whetherbees do so when they dance, or whether birds monitor their calls. It is notknown if birds monitor their song; it is likely that they do.

3. Specialization The communication system serves no other function but tocommunicate.

Human language represents realityboth external (real world) and internal(states, beliefs)symbolically in the mind. Manifested as speech, languageserves uniquely as a communicative system. Bee dancing and birdsong alsoappear to be specialized communicative activity. Alarm calls of any speciesmay be symptomatic but at the same time are specialized for different types ofpredators. Symptomatic tokens, on the other hand, are unspecialized. Cryingis a symptomatic sign that may be interpreted by someone else and thus func-tion communicatively, but its primary purpose is physiological (the clearingof foreign matter from the eye, the release of emotional tension). If animalcommunication is primarily symptomatica claim that is hotly disputed byspecialists in animal communicationthen it would not qualify as a special-ized communicative system.

4. Semanticity The system conveys meaning through a set of fixed relationshipsamong signifiers, referents, and meanings.

Human language conveys meaning through arbitrary symbols. Bee dancing con-veys meaning, but within a very limited range, as do bird calls and song. The rangeof meaning is broader and more subtle in nonhuman primate vocalizations.




Although we cannot claim to know the minds of such near relatives as chim-panzees and gorillas, it appears that the range of meanings suggested by theirbehavior in the wild does not approach the vastness of human semanticity(see feature 8).

5. Arbitrariness There is no natural or inherent connection between a token and itsreferent.

This is true of human language, with the possible exception of a few ono-matopoeic terms. Bee dancing shows arbitrariness in that there may be no con-nection between the form of the dance and the distance from the hive.Expressions of food source quality and direction are not arbitrary, however.Many bird calls are highly suited for their purpose, such as danger calls whichare difficult to locate, and in this sense are not arbitrary. Most nonhuman pri-mate vocalization appears to be equally adaptive, though arbitrariness has beenclaimed for vervet monkey alarm calls.

6. Discreteness The communication system consists of isolatable, repeatable units.

Human language shows distinctive features, phonemes, syllables, morphemes,words, and still larger combinations. There are two (three, in some dialects) discretetypes of bee dances, but these dances are not combined in various ways to producenovel messages. There is some evidence for subunits in birdsong. They are also pres-ent in primate call systems.

7. Displacement Users of the system are able to refer to events remote in spaceand time.

Bee dancing shows displacement. No evidence for displacement is found in birdcalls or songs. Baboons occasionally produce threat and fight vocalizations long afteran aggressive encounter, but there is no evidence that this is reflecting displacement;it probably reflects a slow winding down of the animals emotional state. Amongapes, it is not yet clear whether some degree of displacement is a feature of eithertheir communication in the wild or the systems they have learned from humans.Nonhuman primates do not appear to communicate about imaginary pasts orfutures, which humans are able to do with language.

8. Productivity New messages on any topic can be produced at any time.

This is obviously tr