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溝通的演化 (The Evolution of Communication) ─ 動物行為學 (Ethology) 鄭先祐 (Ayo) 國立 臺南大學 環境與生態學院 生態科學與技術學系 教授 Ayo NUTN Web:

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Presentation on theme: "溝通的演化 (The Evolution of Communication) ─ 動物行為學 (Ethology) 鄭先祐 (Ayo) 國立 臺南大學 環境與生態學院 生態科學與技術學系 教授 Ayo NUTN Web:"— Presentation transcript:

1 溝通的演化 (The Evolution of Communication) ─ 動物行為學 (Ethology) 鄭先祐 (Ayo) 國立 臺南大學 環境與生態學院 生態科學與技術學系 教授 Ayo NUTN Web: 大學部 生態學與保育生物學學程 ( 必選 ) 2010 年 秋冬

2 Ayo 教材 ( 動物行為學 2010) 2 Part 3. 個體間的互動 生殖行為 (Reproductive Behavior) 親代照顧與交配體系 (Parental Care and Mating Systems) 溝通:管道與功能 (Communication: Channels and Functions) 溝通的演化 (The Evolution of Communication) 衝突 (Conflict) 團體生活,利他和合作 (Group Living, Altruism, and Cooperation)

3 Ayo 教材 ( 動物行為學 2010) 3 15b 溝通的演化 The changing views of communication Sharing information Manipulating others Signals and honesty The evolutionary origins of signals Retualization Receiver-bias mechanisms Selective forces that shape signals Language and apes What is language? Ape language studies Communication and animal cognition ( 認知 ) Communication: Evolution By Goodenough, McGuire, and Jakob

4 Ayo 教材 ( 動物行為學 2010) 4 Views about communication are changing We can answer the questions of who, what, where, and when of the communication process But it is difficult to answer questions of how and why have signals taken various forms that they have Communication involves the transmission of information from one animal to others A cooperative view of communication: both sender and receiver benefit from the accurate transfer of information Selection should make signals efficient, reliable, and unambiguous Dishonest or inaccurate signaling was thought to be unlikely

5 Ayo 教材 ( 動物行為學 2010) 5 Animals manipulate other animals The cooperative view of communication does not fit every situation A sender might gain by sending an inaccurate signal In a territorial dispute, the sender might bluff by sending signals that exaggerate its willingness to escalate the contest A male competing for a female’s attention might exaggerate his qualities

6 Ayo 教材 ( 動物行為學 2010) 6 Dishonesty may benefit an animal An animal that gives a dishonest signal gains an advantage Over animals that honestly communicate their abilities or intentions So, animals don’t communicate to convey information But to manipulate the behavior of others to their own advantage

7 Ayo 教材 ( 動物行為學 2010) 7 Signals: normally reliable, occasionally deceptive An animal produces a signal when, on average, it increases its own reproductive success By influencing the behavior of others For signals to evolve, they must benefit senders overall Senders may not be trustworthy If signals are potentially dishonest, why not just ignore them? On average, the receiver must benefit from responding to signals Even if it is sometimes deceived

8 Ayo 教材 ( 動物行為學 2010) 8 When are honest signals likely? Four circumstances under which we expect to see honest signals: When senders and receivers share overlapping goals When signals indicate something about the sender that cannot be faked When signals are costly to produce When dishonest signalers can be identified

9 Ayo 教材 ( 動物行為學 2010) 9 Honest signals: senders and receivers share goals Natural selection favors unambiguous, honest signals for coordination of mating activities The sexes share overlapping goals in the relationship between parent and offspring But even this relationship can entail significant conflict Altricial baby bird s( 幼鳥 ) beg their parents to feed them Baby birds stand, gape, flap their wings, and call

10 Ayo 教材 ( 動物行為學 2010) 10 Honest communication Begging chicks are obvious to predators Begging too much, when food is not needed, is a poor strategy Parents provide food to chicks that beg most vigorously Parents respond because their own fitness depends on the survival of their offspring Communication between baby birds and parents is honest Other examples of similar goals of the sender and receiver Belding’s ground squirrels call to warn relatives of a predator Every bee benefits when scouts convey the location of a patch flowers

11 Ayo 教材 ( 動物行為學 2010) 11 Honest signals: signals cannot be faked Signals are honest because they are tightly linked to a trait of the sender The sender simply cannot fake the signal Size is a good predictor of fighting success Displays allow opponents to judge one another’s size Combatants( 戰鬥人員 ) enhance their apparent size Puffing up their feathers Fluffing out their fur Assuming an upright posture In other species, size is not so easily faked

12 Ayo 教材 ( 動物行為學 2010) 12 Male stalk-eyed flies send honest signals During an aggressive display, these flies strike a pose that Allows each competitor to compare the length of its eyestalks Males with shorter eyestalks usually retreat without a fight

13 Ayo 教材 ( 動物行為學 2010) 13 Honest signals are linked to an animal ’ s health Bright red and yellow feathers, scales, or fleshy necks or combs of some birds Depend on chemicals called carotenoids Carotenoids must be obtained in the diet These bright colors honest signal of foraging ability and health Female house finches prefer brighter, redder males Females benefit from their choice Brighter males are better parents Bringing more food to the nestlings.

14 Ayo 教材 ( 動物行為學 2010) 14 Honest signals: are costly to produce What prevents a male from exaggerating his qualities? Handicap principle ( 障礙原則 ): reliable signals are favored when signals are costly to the sender Their very extravagance indicates the owner’s qualities These signals are handicaps Their owners are perceived as doing well In spite of the handicap of investing in the signal

15 Ayo 教材 ( 動物行為學 2010) 15 Criteria for a signal to evolve as a handicap The signal must be costly It must relate to the quality of the sender The receiver must be interested in the quality of the sender that is being signaled And must benefit from attending to an honest signal Receivers benefit from correctly assessing the quality of a signaler Especially in the context of sexual selection

16 Ayo 教材 ( 動物行為學 2010) 16 Signals may be costly Energetic costs are the most common measurements Oxygen consumption increases in insects and frogs Male red deer lose weight during the rut cost ( 發情代價 ) Other costs: decreased ability to move, escape, or forage Long tail feathers of male birds serve as sexual ornaments And impair their ability to fly Higher-quality senders can pay the cost of higher-quality signals Brighter colors, vigorous displays Only male red deer in top physical condition can continue roaring ( 咆嘯 ) to win the vocal duel ( 聲音對抗 )

17 Ayo 教材 ( 動物行為學 2010) 17 Honest signaling in the blue-footed booby Seabirds with brightly colored feet During their courtship ritual, boobies stand facing one another The male lifts his feet to display them to the female Males in good condition have bright blue-green feet Unfed males have dull blue feet Females prefer males with brightly colored feet 藍腳鰹鳥

18 Ayo 教材 ( 動物行為學 2010) 18 blue-footed booby ( 藍腳鰹鳥 ) blue penguins : Few penguin interactions end in fighting because they suffer flesh wounds and sometimes eye loss

19 Ayo 教材 ( 動物行為學 2010) 19 Signal costs also affect receivers In the form of the response of receivers to the signal Little blue penguins have aggressive displays that differ in Cost (risk of injury) Effectiveness in deterring an opponent Ability to predict an attack A penguin conveys information about its willingness to sustain injury while performing the display And its willingness to fight

20 Ayo 教材 ( 動物行為學 2010) 20 Penguin displays are honest Because aggressive encounters are potentially costly Attempting to intimidate ( 威嚇 ) an opponent into retreat could be costly If the rival called the bluff ( 嚇唬 ) Penguin encounters begin with low-risk displays They escalate until one opponent retreats or a fight occurs One “bidder” decides that the territory is not worth the risk

21 Ayo 教材 ( 動物行為學 2010) 21 Honest signals: dishonest signalers can be identified A stable social unit favors honest communication Individuals both send and receive signals at different time The advantages of sending dishonest signals would be reversed When the animal is the receiver So honesty predominates in the population Members of social units recognize one another And learn whether a particular individual is honest

22 Ayo 教材 ( 動物行為學 2010) 22 Vervet monkeys don ’ t believe dishonest signalers Members of a social group stop believing an individual that gives unreliable signals Vervet monkeys have two different calls that warn of another group of monkeys on their territory Monkeys stopped responding and no longer believed a liar

23 Ayo 教材 ( 動物行為學 2010) 23 Vervet monkey alarm calls that alert group members of the approach of a neighboring troop are of two types. The “chutter” warns that another group is nearby. The “wrr” is given when another group is spotted in the distance.

24 Ayo 教材 ( 動物行為學 2010) 24 Dishonest signals: senders and receivers have different goals Different goals set the stage for deception ( 欺騙 ) A father bird and his chick share the goal of the chick’s survival But the chick may want more parental investment than the father would like to give At the cost of his other chicks or his future reproduction Signals between parents and chicks are essentially honest But with some attempt by the chick at manipulation and deceit

25 Ayo 教材 ( 動物行為學 2010) 25 Some signals are bluffs ( 嚇唬 ) Honest signals can be corrupted by dishonest bluffs Stomatopods (mantis shrimps) 蝦蛄 ferociously defend their burrows Stomatopods have two appendages used in prey capture and territorial defense Combatants may be injured or killed during battles

26 Ayo 教材 ( 動物行為學 2010) 26 Stomatopods (mantis shrimps) 蝦蛄

27 Ayo 教材 ( 動物行為學 2010) 27 Mantis shrimp ( 蝦蛄 ) signal their readiness to attack Readiness to attack is signaled by a threat display (meral spread) A newly molted stomatopod is defenseless But still gives the meral spread display Its opponent is deceived and retreats A stomatopod can get away with the bluff The receiver would pay dearly ( 付出昂貴代價 ) if it tested the honesty of the signal The signal is stable because, on average, it is honest

28 Ayo 教材 ( 動物行為學 2010) 28 Honest and dishonest signals coexist The costliness of signals can reinforce honesty When signals are generally honest A low level of deceit is stable and is expected to evolve Populations are in flux At any time dishonesty may spread A signal may be perceived by different receivers Some have the same goals as the sender (i.e. prospective mate) Some have different goals (a competitor) A mixed signaling strategy, sometimes honest and sometimes deceptive, may be best

29 Ayo 教材 ( 動物行為學 2010) 29 The evolutionary origins of signals Two approaches may explain the evolutionary origins of signals Identifying the behaviors of the senders that form the raw material for signals Ritualization Focusing on how signals exploit the receiver’s sensory biases Ability to detect some information better than others These two evolutionary pathways are not mutually exclusive

30 Ayo 教材 ( 動物行為學 2010) 30 Ritualization Many signals get their start as part of another behavior Or as a physiological response That takes on a signaling function later Ritualization: evolution favors modification of the incipient signal It becomes more stereotyped and unmistakable The three sources of raw material for signals are 1.Intention movements 2.Displacement activities 3.Autonomic responses

31 Ayo 教材 ( 動物行為學 2010) Intention movements Animals begin behavior patterns with characteristic movements That prepare them for action It is possible to judge what the animal intends to do A wolf pulls back its lips and bares its teeth before biting It improves another wolf’s fitness if he correctly interprets the bared teeth Rather than waiting to get bit

32 Ayo 教材 ( 動物行為學 2010) 32 Avian displays originated with intention movements For flight or walking A bird about to fly crouches, points its beak, raises its tail, and spreads its wings Components of the takeoff leap have been ritualized into communicative signals The blue-footed booby incorporates “sky pointing” into its courtship dance This display originated in flight But changed during ritualization

33 Ayo 教材 ( 動物行為學 2010) Displacement activities Irrelevant actions performed in situations in which an animal has conflicting motivations and is thus indecisive ( 無法決斷 ) Faced with an aggressor, an animal may have conflicting motivations To fight and to flee So it may instead preen itself ( 鳥 ) 用喙理 ( 毛 ); Displacement activities are often incomplete actions Courtship is a time of conflicting tendencies Sexual partners must come together to mate In spite of aggressive tendencies that keep them apart

34 Ayo 教材 ( 動物行為學 2010) 34 Displacement activities in male ducks Mock preening of the courtship displays of male ducks Originated in displacement preening

35 Ayo 教材 ( 動物行為學 2010) Autonomic responses The autonomic nervous system ( 自主神經系統 ) regulates many basic body functions Digestion, circulatory activities, heart rate, diameter of the blood vessels, thermoregulation Displays may have originated from autonomic functions At times of stress or conflict The naked head or neck skin of turkey, jungle fowl, and bateleur flush ( 發紅 ) and swell ( 腫脹 )during stress because of vasodilation These changes are now part of signaling during courtship and aggressive encounters

36 Ayo 教材 ( 動物行為學 2010) 36 Evolution of signals from the respiratory system Modifications of the respiratory system produce sound signals And visual signals In inflation displays of birds, males fill pouches with air to attract mates The male frigate bird’s throat pouch inflates to an enormous size and brilliant color to attract females

37 Ayo 教材 ( 動物行為學 2010) 37 Evolution of signals from thermoregulation Piloerection (erection of feathers and hair) traps heat It is also a part of aggressive( 攻擊 ) and appeasement( 緩和 ) displays A zebra finch that cannot escape from a dominant individual Fluffs its feathers as an appeasement signal Feather position can be part of courtship displays Tail-raising courtship display of the peacock ( 孔雀 ) In mammals the message’s meaning varies with the part of the body on which hair is erected If all the hair is erect on tamarins ( 狨猴 ) : attack or be indecisive If only the tail hair is erected: flee ( 逃走 )

38 Ayo 教材 ( 動物行為學 2010) 38 zebra finch tamarins ( 狨猴 )

39 Ayo 教材 ( 動物行為學 2010) 39 Other behaviors as raw materials for displays Ritualization is a highly opportunistic evolutionary process It can be launched from almost any behavior pattern, anatomical structure or physiological change Predatory behaviors have been ritualized in the male gray heron ( 灰鷺 ) During courtship, he erects his crest and body feathers Points his head downward and snaps his mandibles closed Movements are similar to those used during fishing

40 Ayo 教材 ( 動物行為學 2010) 40 gray heron ( 灰鷺 ) Masked lovebirds

41 Ayo 教材 ( 動物行為學 2010) 41 Food exchange has also been ritualized The touching of bills is derived from the parental feeding Is common in courtship and appeasement display Establishes or maintains bonds Masked lovebirds bill during greetings and after a spat

42 Ayo 教材 ( 動物行為學 2010) 42 Flight can also be ritualized Yellow-headed blackbirds and red-winged blackbirds perform aerial displays to entice( 誘惑 ) females Ritualized flight is more conspicuous than normal flight Movements are accentuated and reveal plumage patterns Courtship displays of the fiddler crab evolved from the movement of the male while entering his burrow

43 Ayo 教材 ( 動物行為學 2010) 43 Ritualized flight in blackbirds.

44 Ayo 教材 ( 動物行為學 2010) 44 The ritualization process During the evolutionary process of ritualization Signaling behaviors become more stereotyped They may also change Slow down, speed up, become more exaggerated Anatomical features (colors, claws) might evolve to draw attention to the display Emancipation ( 解放 ): behaviors that become freed from the internal and external factors that originally caused them The original triggers no longer cause the behavior to occur The behavior has only a communicative function

45 Ayo 教材 ( 動物行為學 2010) 45 Evolution of the whistle-shake in ducks The body-shake is the evolutionary precursor of the whistle-shake in ducks Serves to dry and rearrange the feathers Whistle-shakes resemble body shakes But are ended by the duck tilting( 翹起 ) back its head and emitting a trill ( 顫音 ) And are given in social situations Some signals are not completely emancipated from their original causes Whistle shakes are still given in response to water sprays

46 Ayo 教材 ( 動物行為學 2010) 46 Receiver-bias mechanisms Ritualization focuses on characteristics of the sender Sensory exploitation hypothesis: the receiver has a preexisting preference for a particular signal Features of the receiver’s nervous system makes it more responsive to a particular form of stimulus The sender takes advantage of the receiver’s preexisting sensory biases when new signals are evolving. Evolution of swordtails ( 劍尾魚 ) in fish

47 Ayo 教材 ( 動物行為學 2010) 47 Sensory bias in frogs Female túngara frogs prefer males with lower frequency chuck calls Female túngara frogs benefit from their preference Low-frequency chucks are produced by larger males Resulting in more fertilized eggs

48 Ayo 教材 ( 動物行為學 2010) 48 Sensory bias in water mites Male courtship signals have exploited the females’ sensory adaptations for prey detection Water mite hunts by ambush When a courting male detects a female he moves his legs These vibrations mimic prey Leading the female to grab him

49 Ayo 教材 ( 動物行為學 2010) 49 Sender characteristics shape signals Anatomical structures form the foundation for producing signals i.e. sensory organs of electric fish Body form (i.e. size) influences signal design Small species not be visible, so other sensory modalities are favored for long-distance communication Physical characteristics may evolve that enhance visual signals (i.e. facial expression, erection of hair) Smaller species give more acrobatic ( 特技的 ) displays In vertebrates it influences vocalizations

50 Ayo 教材 ( 動物行為學 2010) 50 Signal evolution does not happen in a vacuum Many signals are produced by structures that have other functions Body size, hair, beaks, and respiratory tracts are under selection for other reasons Besides their role in producing signals For example, beak shape in Darwin’s finches is important in Feeding behavior Song production

51 Ayo 教材 ( 動物行為學 2010) 51 Environmental characteristics affect the choice of communication The habitat helps determine which channel of communication (sound, chemical, visual, etc.) a species uses Visual signals are not much use in the ocean’s depths So whales rely on sound for long-distance communication The habitat affects sound transmission Attenuation (weakening): how far the sound will carry Degradation: how distorted the signal becomes during transmission

52 Ayo 教材 ( 動物行為學 2010) 52 The acoustic adaptation hypothesis Acoustic properties of bird song are shaped by habitat structure Songs attenuate and degrade differently in different environments Songs are more attenuated and degraded in dense foliage Lower frequencies become less distorted in dense foliage In habitats with complex vegetation structure Songs should have low frequencies, narrow bandwidths Whistles and long notes In open habitat (i.e. grasslands) Songs should have high frequencies and broad bandwidths Trills and short notes

53 Ayo 教材 ( 動物行為學 2010) 53 Habitat structures influence bird songs Great tits have a large geographic distribution Forest dwellers sing songs with a lower pitch A narrower range of frequencies Fewer notes per phrase than open woodland birds No differences were found between other species in different habitats But a review of the literature (meta-analysis) shows that Habitat structure weakly influences acoustic properties of bird songs

54 Ayo 教材 ( 動物行為學 2010) 54 Displays vary according to the background The environment influence transmission of other channels of communication Visual signals differ in visually “noisy” versus plain environments Many lizard species rely on visual displays Head bobs, push-ups, back arching, extension of the dewlap and tail flicks

55 Ayo 教材 ( 動物行為學 2010) 55 Lizard displays and background motion Jacky lizard species that live in trees display faster and flick their tails more When it is windy and the vegetation moves Senders of signals may change their behavior when the environment changes

56 Ayo 教材 ( 動物行為學 2010) 56 Jacky lizard

57 Ayo 教材 ( 動物行為學 2010) 57 Habitat changes caused by humans Human activities alter the environment in which animals communicate And alter selection pressures on signal form Great tits do well in both urban and rural environments Urban birds sing shorter, faster songs with higher minimum frequencies Most likely due to competition with the noise of the urban background

58 Ayo 教材 ( 動物行為學 2010) 58 Human-induced environmental changes affect visual signals Visual signals can be impeded ( 阻礙 ) The Baltic Sea has grown turbid (cloudy) Making it harder for female stickleback fish to see males Males have to court much more vigorously to get the female’s attention The honesty of male signals is reduced because males are not as likely to see each other

59 Ayo 教材 ( 動物行為學 2010) 59 Receiver characteristics: sensory drive Sensory drive: the environment shapes receiver characteristics Surfperch ( 海鯽 ) are marine fish that live in a variety of habitats Differing in light intensity and variability The retinas of surfperch species differ They are good at detecting differences in color contrast Or differences in brightness But not both

60 Ayo 教材 ( 動物行為學 2010) 60 Different optical habitats of related surfperch species. (left) live in an environment that is highly variable in light intensity. Striped surfperch (right) live in deeper water in the kelp forest where the background light is more even. Deepwater surfperch are better at detecting brightness differences Species living in shallow water can better see color differences

61 Ayo 教材 ( 動物行為學 2010) 61 Language and apes Humans are very interested in what separates us from other species Tool use was thought to be confined to humans But this is not the case Language seems to clearly be a talent confined to humans Which elements of language are unique to humans Which are more broadly shared? Are differences a matter of kind or degree?

62 Ayo 教材 ( 動物行為學 2010) 62 True language has four elements 1. Words or signs must be used as true symbols That stand for, or take the place of, a real object, event, person, action, or relationship 2. Symbols should permit reference to objects or events That are not present 3. There should be some elements of grammar (rules) That determine the relationship between words Changing the order of symbols alters the meaning of the message 4. Words or signs should be combined to form novel phrases Or sentences that are understandable to others

63 Ayo 教材 ( 動物行為學 2010) 63 Early studies taught chimps to talk Researchers have studied the ability of great apes (chimpanzees, western (lowland) gorillas orangutans, bonobos) to learn language A chimp named Viki was taught to say three words “Mama,” “papa,” and “cup” These attempts failed Chimpanzees lack the vocal apparatus to make the range of sounds of human speech

64 Ayo 教材 ( 動物行為學 2010) 64 Studies taught chimps nonverbal languages Washoe, a young chimpanzee, was taught American Sign Language (ASL) Washoe and other chimps were reared like human children Spoken English was not allowed Washoe had a vocabulary of 132 signs Her signs were not restricted to requests She applied them correctly to a wide variety of referents She extended the sign for dog from a picture to all pictures of dogs, living dogs, and even the barking of an unseen dog

65 Ayo 教材 ( 動物行為學 2010) 65 Washoe signs with ASL Washoe combines signs to denote “water bird” for a swan

66 Ayo 教材 ( 動物行為學 2010) 66 Stop and think: Do you agree that the best way to test whether apes have linguistic skills is to incorporate them into human society as much as possible? What are the advantages and disadvantages of this approach?

67 Ayo 教材 ( 動物行為學 2010) 67 Koko, Chantek and Nim Chimpsky A gorilla named Koko and an orangutan named Chantek were taught ASL Spoken English was permitted Emphasized the production of language (the use of signs) Not comprehension (understanding the meaning of signs) Nim Chimpsky a young male chimp, was accused of imitating his trainers But Nim’s language abilities were stunted( 受礙 ) by the operant-conditioning procedures used in his training And Nim’s trainers changed so often that he could not form the relationships essential for language development

68 Ayo 教材 ( 動物行為學 2010) 68 It was accepted that chimpanzees could not learn language But when other trainers worked with Nim His language skills improved Chantek’s signs were more spontaneous Could not be attributed to imitation Washoe and the other language-trained chimps Signed to other animals and objects And frequently to themselves Washoe adopted a ten-month-old infant named Loulis Loulis learned his first 55 signs by observing other chimps Washoe and her family signed to one another their daily activities (playing, eating, family fights)

69 Ayo 教材 ( 動物行為學 2010) 69 Sarah used plastic chips as words The chimpanzee Sarah used a particular plastic chip as a word To complete a preformed statement She arranged four to five words into a sentence Sarah named many objects and used complicated relationships Such as if-then and same-different

70 Ayo 教材 ( 動物行為學 2010) 70 The LANA Project A chimpanzee named Lana was trained to use a computer to communicate Eliminating social cueing and the difficulty of interpreting symbols Lana communicated in Yerkish, a symbolic language Yerkish words (lexigrams) are geometric figures Pressing a computer key labeled with the lexigram selects words

71 Ayo 教材 ( 動物行為學 2010) 71 The LANA Project Lexigrams had to be used in an appropriate order Lana had to learn syntax - rules governing word order She developed a large vocabulary and mastered grammar She also coined new words She called an orange soda a “Coke-which-is-orange”

72 Ayo 教材 ( 動物行為學 2010) 72 Apes learn words in various forms To refer to objects not present Stringing words together in short sequences Follow rules of grammar They coin new words But do apes use words as symbols? When a chimp uses a “word” (sign, plastic chip, or lexigram) to name an object Is it used as a symbol that stands for the object Or is it a label that is associated with the object through a reward system?

73 Ayo 教材 ( 動物行為學 2010) 73 Using “ words ” as true symbols Two chimpanzees, Sherman and Austin communicated with each other symbolically By pressing computer keys with lexigrams The emphasis was on interanimal communication, They were not taught to produce strings of lexigrams Or to adhere to grammatical rules

74 Ayo 教材 ( 動物行為學 2010) 74 Chimps communicate with each other Sherman and Austin specify foods to one another using lexigrams They communicate with each other Regardless of which of them is the observer

75 Ayo 教材 ( 動物行為學 2010) 75 Chimps use symbols in communication To inform each other of the appropriate tool to use to solve a problem Clearly using words as symbols and not simply labeling objects This shifted the emphasis from demonstrating that apes can produce language To showing that they can understand symbols or words of language It also showed how important the learning environment is in developing language comprehension

76 Ayo 教材 ( 動物行為學 2010) 76 Kanzi and Panbanisha Bonobo (pygmy) chimpanzees Kanzi was adopted and raised by Matata And was always present during Matata’s training sessions After Kanzi was separated from Matata He used symbols on the keyboard that they had tried to teach to Matata Not only did he know the lexigrams He also knew the English words that the lexigrams represented

77 Ayo 教材 ( 動物行為學 2010) 77 Kanzi has a large vocabulary Kanzi learned communication skills by observing his mother’s training Much the same way as a child would Panbanisha, Kanzi’s half-sister Was reared in the same learning environment as Kanzi She, too, shows remarkable comprehension of spoken English Reward-based language training was stopped and replaced with conversation Kanzi’s human companions served as communicative models

78 Ayo 教材 ( 動物行為學 2010) 78 Kanzi learned symbols through observation Kanzi communicates using a board with 256 lexigrams Kanzi observed and interacted with humans who used gestures and lexigrams to communicate

79 Ayo 教材 ( 動物行為學 2010) 79 Kanzi and others understand spoken English Besides being able to produce language Kanzi was not trained to vocalize But spontaneously makes sounds with different content Chimpanzees utter natural sounds when they find food Producing distinct grunts when encountering different foods This skill is found in other animals besides apes Including vervet monkeys and even chickens Ape communication fulfills the four requirements of language

80 Ayo 教材 ( 動物行為學 2010) 80 Communication and animal cognition Do nonhuman animals have thoughts or subjective feelings? Are they are aware of other animals’ feelings? Are they cognitive, conscious, aware beings? Tapping animals’ communication lines can indicate whether animals have conscious thoughts or feelings If nonhuman animals thoughts and feelings They probably communicate them to others through their communication signals

81 Ayo 教材 ( 動物行為學 2010) 81 Evidence of cognition: forming mental representations Of objects or events that are out of sight Some animal signals are symbolic They refer to things that are not present Some animals learn a language that uses symbols i.e. apes

82 Ayo 教材 ( 動物行為學 2010) 82 Other species understand symbols Alex the parrot could vocally request more than 80 items Even if they were out of sight He could quantify and categorize these objects He understood the concepts of color, shape, and same versus different for both familiar and novel objects Bottlenosed dolphins also understand symbolic languages “Words” are gestures or are generated by a computer They can refer to objects, actions, and relationships Dolphins understand experimenter’s references to objects that are not present

83 Ayo 教材 ( 動物行為學 2010) 83 Evidence of cognition( 認知 ): natural communication systems Language involves the ability to relate words to meanings In some species, individuals classify signals by their meaning Not by some obvious physical property (the way a signal sounds) When a rhesus monkey finds food It announces this with one or more of five different food calls A different type of call announces if the item is of high quality or rare

84 Ayo 教材 ( 動物行為學 2010) 84 Classifying calls by meaning or sound Animals habituate (gradually stop responding) to a stimulus that is repeated many times without consequence If monkeys classify a food call by its sound After habituating to one type of call they still respond to any other type of call because it sounds different If they classify a food call by its meaning They will be unresponsive to a call in the same category But remain responsive to a call in a different category Rhesus monkeys classify calls by their meaning.

85 Ayo 教材 ( 動物行為學 2010) 85 Evidence of cognition: understanding mental states of others Does a communicating animal understand what potential receivers know? Vervet monkeys apparently do not Mother vervet monkeys give alarm calls when they sense a predator But do not take into account whether their offspring are ignorant or knowledgeable about the predator

86 Ayo 教材 ( 動物行為學 2010) 86 Langurs call to their audience Male Thomas langurs give alarm calls But only if there is an audience Males call persistently after spotting a predator Stopping only when every other member in the group also gave an alarm call Callers seem to keep track of all the other members in their groups

87 Ayo 教材 ( 動物行為學 2010) 87 Ethical ramifications of cognition in animals The question of animal awareness is difficult to answer scientifically The answer has ethical ramifications If the line between animals and humans is erased or even smudged a bit, should we rethink the way we treat animals? Should we keep them in zoos? Should great apes be used for language studies? What about dolphins? So what’s your opinion? Are animals aware, cognitive beings? All of them? Where do we draw the line?

88 Ayo 教材 ( 動物行為學 2010) 88 Summary Signals should be honest, unambiguous and informative Sometimes the sender of a signal benefits from being dishonest On average, a sender manipulates the behavior of others to its own advantage Receivers should respond to signals when they benefit from them, on average, even if they are sometimes deceived Conditions for honest signals (1) senders and receivers share overlapping goals, (2) they cannot be faked, (3) they are costly to produce, and (4) dishonest signalers can be identified Conditions that favor dishonest signals (1) senders and receivers have different goals, (2) they are costly to assess or to challenge

89 Ayo 教材 ( 動物行為學 2010) 89 Summary Honest and dishonest signals can coexist in a population Signals originate through ritualization and sensory exploitation Evolutionary sources of ritualization (1) intention movements, (2) displacement activities, and (3) autonomic responses The design of the signal may be influenced by the anatomy and physiology of the sender and the habitat Most animal communication signals are not true language They do not use symbols that can replace their referent They do not string signals together to form novel sentences Researchers have attempted to teach apes language Some animals understand signals that represent unseen items

90 Ayo 教材 ( 動物行為學 2010) 90 問題與討論 Ayo 台南 NUTN 站


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