The Handicap Principle A Missing Piece of Darwin's Puzzle

by Zahavi, Amotz; Zahavi, Avishag; Ely, Na'ama; Ely, Melvin Patrick; Balaban, Amir

• ISBN13: 9780195100358
• ISBN10: 0195100352
• Format: Hardcover
• Copyright: 1997-08-07
• Publisher: Oxford University Press

Summary

Ever since Darwin, animal behavior has intrigued and perplexed human observers. The elaborate mating rituals, lavish decorative displays, complex songs, calls, dances and many other forms of animal signaling raise fascinating questions. To what degree can animals communicate within their own species and even between species? What evolutionary purpose do such communications serve? Perhaps most importantly, what can animal signaling tell us about our own non-verbal forms of communication? In The Handicap Principle , Amotz and Ashivag Zahavi offer a unifying theory that brilliantly explains many previously baffling aspects of animal signaling and holds up a mirror in which ordinary human behaviors take on surprising new significance. The wide-ranging implications of the Zahavis' new theory make it arguably the most important advance in animal behavior in decades. Based on 20 years of painstaking observation, the Handicap Principle illuminates an astonishing variety of signaling behaviors in animals ranging from ants and ameba to peacocks and gazelles. Essentially, the theory asserts that for animal signals to be effective they must be reliable, and to be reliable they must impose a cost, or handicap, on the signaler. When a gazelle sights a wolf, for instance, and jumps high into the air several times before fleeing, it is signaling, in a reliable way, that it is in tip-top condition, easily able to outrun the wolf. (A human parallel occurs in children's games of tag, where faster children will often taunt their pursuer before running). By momentarily handicapping itself--expending precious time and energy in this display--the gazelle underscores the truthfulness of its signal. Such signaling, the authors suggest, serves the interests of both predator and prey, sparing each the exhaustion of a pointless chase. Similarly, the enormous cost a peacock incurs by carrying its elaborate and weighty tail-feathers, which interfere with food gathering, reliably communicates its value as a mate able to provide for its offspring. Perhaps the book's most important application of the Handicap Principle is to the evolutionary enigma of animal altruism. The authors convincingly demonstrate that when an animal acts altruistically, it handicaps itself--assumes a risk or endures a sacrifice--not primarily to benefit its kin or social group but to increase its own prestige within the group and thus signal its status as a partner or rival. Finally, the Zahavis' show how many forms of non-verbal communication among humans can also be explained by the Handicap Principle. Indeed, the authors suggest that non-verbal signals--tones of voice, facial expressions, body postures--are quite often more reliable indicators of our intentions than is language. Elegantly written, exhaustively researched, and consistently enlivened by equal measures of insight and example, The Handicap Principle illuminates virtually every kind of animal communication. It not only allows us to hear what animals are saying to each other--and to understand why they are saying it--but also to see the enormously important role non-verbal behavior plays in human communication.

Table of Contents

Acknowledgements	xi	(2)
INTRODUCTION THE GAZELLE, THE WOLF, AND THE PEACOCK'S TAIL	xiii
PART I PARTNERS IN COMMUNICATION	3	(40)
CHAPTER 1 PREY-PREDATOR INTERACTIONS Alarm calls: a message to friends or to foes? Stotting as communication with predators. Calls by prey during pursuit: the merlin and the skylark. Warning colors (aposematic coloration). Signaling to prey. Cooperation between prey and predators without communication. Preconditions for prey-predator communication.	3	(12)
CHAPTER 2 COMMUNICATION BETWEEN RIVALS Threats as a substitute for aggression: are humans worse than beasts? Handicaps as keys for reliable threats. Threats by approaching. Threats by stretching--deceit or exposure to danger? Threats by vocalization. Other threats. Social hierarchies and duels between equals. Can threat signals evolve for the good of the group? The drawbacks of "group selection."	15	(10)
CHAPTER 3 MATE SELECTION The conflict inherent in courtship. Courtship handicaps and the information they convey: feeding ability, superterritories, courtship vocalization, colors, scents (pheromones), artifacts and constructions, combinations of Signals, long tails, movements and dances. Leks: congregating for display. Polymorphic species and males that mimic females. Fisher's model of the Runaway Process compared with the Handicap Principle. Utilitarian selection and signal selection.	25	(18)
PART II METHODS OF COMMUNICATION	43	(68)
CHAPTER 4 THE FALLACY OF SPECIES-SPECIFIC SIGNALS Did decoration evolve to identify species, gender, and age? The evolution of common markings through competition between individuals. Markings and the traits they advertise: lines and stripes, patches and frames that bring out body parts. Implications of the Handicap Principle: the use of markings to focus on features. Symmetry. "Eye" patterns. The evolution of markings; polymorphism and convergence. Facial markings and the direction of gaze. Status badges or handicaps? Are there signals without handicaps? Are there any signals that are conventions? The definition of signals; inflation as a test of the theory of signal selection.	43	(18)
CHAPTER 5 MOVEMENTS AND RITUALIZATION Difficult movements. Ritual fighting. Ritualization: does it reduce the information conveyed? How a ritualized signal evolves.	61	(8)
CHAPTER 6 VOCALIZATIONS The correlation of voice with posture and tension. The information conveyed by vocal signals. Animal vocabularies: the connection between the message and its vocal pattern. Rhythm. Vocal patterns used over distance. Why shout? The duration of vocalization: requests and commands. Dialogues and their significance. Mimicry. Do animals have verbal language?	69	(12)
CHAPTER 7 BODY PARTS THAT SERVE AS SIGNALS Long tails: are they signals? Bristling hair or feathers: an illusion of size, or a handicap? Manes and crests. Handicaps that interfere with vision. Body parts that emphasize the direction of gaze. Body parts that handicap fighting. Can body parts evolve to reduce the cost of signals? The evolution of horns and antlers. Signal selection and the evolution of feathers.	81	(12)
CHAPTER 8 THE USE OF COLOR FOR SHOWING OFF Black in the desert. Black and white in open spaces. Colors in forests and on coral reefs. The use of two colors. Glossy colors and movement. Exceptions to the rules.	93	(8)
CHAPTER 9 CHEMICAL COMMUNICATIONS Pheromones in butterflies and moths: chemical handicaps. Yeast sex pheromones and propheromones: the role of glycoproteins. Chemical communication within the multicellular body.	101	(10)
PART III THE HANDICAP PRINCIPLE IN SOCIAL SYSTEMS	111	(98)
CHAPTER 10 TESTING THE BOND Testing by imposition. Aggression in courtship. Hide-and-seek: gentler testing in courtship. Clumping, and preening others (allopreening). Group dances and similar rituals.	111	(8)
CHAPTER 11 PARENTS AND OFFSPRING Threats of self-injury: the weapon of the weaker partner. Other methods of blackmail. Exploitation of offspring by parents.	119	(6)
CHAPTER 12 BABBLERS, COMPETITION FOR PRESTIGE, AND THE EVOLUTION OF ALTRUISM Territories, groups, and nonterritorial individuals. Rank, avoidance of incest, and the life strategy of males and of females. The composition of groups; coalitions of males and of females. Struggles without aggression (well, almost). Theories that explain altruism: group-selection theory and its failings. The theory of reciprocal altruism and the problem of enforcement. Competition over altruistic acts in babblers: sentinel activities, feeding of nestlings, feeding of other adults (allofeeding), mobbing. Altruism as a substitute for threats. Rank and prestige. "Shyness" over copulation as a test of male prestige. Reasons for and consequences of living in groups. Prestige and the evolution of altruism: altruism as a handicap.	125	(26)
CHAPTER 13 THE SOCIAL INSECTS: WHY HELP THE QUEEN? The evolution of social structures in the social insects: conditions that favor collaboration: food storage and helpless offspring; the haplodiploid mechanism of gender determination; selection through workers too? How insect colonies form. Why do the workers work for the colony? altruism and prestige; queen pheromones and prestige; the handicap in queen pheromone. Kin selection theory and its drawbacks: parasitism among kin, or Haldane's other brothers; are offspring "kin"? Partnerships among kin: why it makes sense to join the family business. The kin effect.	151	(18)
CHAPTER 14 THE PARENTING COUPLE Paternity and mate-guarding. Taking care of the young to gain prestige. Other means of showing off to one's mate. Dominance between mates. Conditions for female dominance. The parental couple as a partnership.	169	(8)
CHAPTER 15 SOCIAL AMEBAS (CELLULAR SLIME MOLDS) The life cycle of cellular slime molds. Forming the stalk: altruistic suicide? The individual selection hypothesis. DIF as a poison. The difference between prestalk and prespore amebas. Some remaining questions. When is a chemical a signal?	177	(8)
CHAPTER 16 PARASITE AND HOST An arms race or a state of equilibrium? European cuckoos and reed warblers. Great spotted cuckoos and crows. The prestige model. The Mafia model. Accepting a parasite to minimize damage. Neutering the host. From parasite to collaborator. The less virulent parasite as a collaborator against its virulent variant. The implications of assuming a state of equilibrium.	185	(12)
CHAPTER 17 INFORMATION CENTERS Food sources and social organization: the white wagtail. Communal roosts as information centers. Insurance against evil days: winter gatherings of rooks. Flocks and loners: the communal roost of kites in Coto Donana. Bright adults and dull youngsters: handicaps in food squabbles. How information repositories work. Human gatherings. Communal displays at gatherings: promoting the roost or mutual testing?	197	(12)
PART IV HUMANS	209	(20)
CHAPTER 18 HUMANS Innate behavior in humans. The human body and its decorations: hair; eyes, eyebrows, and eyelashes; nose and facial wrinkles; chin and beard; red cheeks and lips; menstruation; breasts and body fat; clothing. Testing the human social bond: the human sexual act as a test of the bond, self-endangerment in humans: suicide as a cry for help. Human language: communication without reliability. Decoration, esthetics, and the evolution of art. Altruism and moral behavior.	209	(20)
Epilogue	229	(2)
Notes	231	(14)
Bibliography	245	(16)
List of Figures	261	(6)
Index	267