Adaptive Behaviour: Understanding the Human Animal Manuel Soler Copyright © 2012 by Manuel Soler ISBN: 978-84-695-2471-8 First published in 2009 in Spanish by Editorial Síntesis Original title: Adaptación del comportamiento: comprendiendo al animal humano To my parents, Dolores Cruz Ruiz and Manuel Soler Serrano. CONTENTS Foreword 4.6.2.1 What is it about males that females select? Preface 4.6.2.2. How do females choose good genes? Chapter 1. Should human behavior be studied from a 4.6.2.3. It is not always the males who biological perspective? compete and the females who choose 4.6.3. Mate selection in humans 1.1. Introduction 4.6.3.1 What do women and men choose 1.2. The uniqueness of human nature when looking for a permanent 1.3. The nature-nurture debate partner? 1.4. Historical problems: the ‘naturalistic fallacy’ 4.6.3.2 Casual sexual relationships and ‘social Darwinism’ 4.6.3.3 Human secondary sexual 1.5. Another controversial matter: the differences characteristics between men and women 4.6.3.4 Sexual selection in modern 1.6. Conclusions industrialised societies 4.7. Male-female conflict when seeking a partner Chapter 2. The scientific method, natural selection and other fundamental matters Chapter 5. Sex, fertilization, sperm competition and sexual selection by cryptic female choice 2.1. Introduction 2.2. The scientific method 5.1. Introduction 2.3. Biological evolution 5.2. Sexual behavior 2.4. Natural selection 5.3. Copulation 2.4.1. Natural selection in modern human 5.4. Sex and copulation in humans: male and female societies orgasms 2.5. Adaptation 5.4.1. Why does sexual desire happen? 2.6. The adaptationist method 5.4.2. Why do we enjoy sex? 2.7. Evolutionary theory: its importance and some 5.4.3. What do the male and female orgasms errors of interpretation signify? 5.5. Male-female conflict in sexual relations Chapter 3. The science of ethology 5.6. Male and female genitalia 5.7. Sperm competition 3.1. Introduction 5.7.1. Preventing the female from copulating 3.2. Ethology: a brief historical overview with another male 3.3. Behavior is heritable 5.7.2. Preventing sperm previously inoculated by 3.4. The objectives of ethology. Tinbergen’s four other males from fertilizing the eggs questions 5.7.3. Taking advantage of work done 3.4.1. The causal approach previously by other males 3.4.2. The ontogenetical or developmental 5.7.4. Human sperm competition approach 5.8. Sexual selection by cryptic female choice 3.4.3. The evolutionary approach 5.9. Fertilization without courtship: alternative (phylogenetical or historical) strategies 3.4.4. The functional or adaptive approach 3.5. Applied ethology Chapter 6. Parental care and mating systems 3.5.1. Animal wellbeing 3.5.2. Conservation 6.1. Introduction 3.5.3. Human societies 6.2. Parental care 6.2.1. Evolution of parental care Chapter 4. Reproduction, finding a mate and sexual 6.2.2. Parental care by males: the importance of selection paternity certainty 6.2.3. Which sex provides parental care? The 4.1. Introduction conflict between males and females 4.2. Reproductive methods 6.2.4. Parent-offspring conflict and sibling 4.3. Why does sexual reproduction exist? conflict 4.4. What is the main difference between males and 6.2.5. Human parental care females? 6.3. Mating systems 4.5. Seeking a mate 6.3.1. Mating system conflict between males and 4.6. Sexual selection: competition between males females and mate-selection by females 6.3.2. Monogamy 4.6.1. Competition for females among males 6.3.3. Polygyny 4.6.1.1. Competition between human 6.3.4. Polyandry males 6.3.5. Polygynandry and promiscuity 4.6.2. Male selection by females 6.3.7. Human mating systems 9.3. The origin and evolution of interspecific Chapter 7. Gregariousness, groups and societies interactions 9.4. Mutualism 7.1. Introduction 9.5. Commensalism 7.2. The costs and benefits of living in a group 9.6. Antagonism 7.3. Adaptations to living in a group 9.6.1. Parasitism 7.4. Group structure: there are not always dominants and subordinates Chapter 10. Animal communication and human 7.5. How are group decisions made? language 7.5.1. Consensual decisions 7.6. Coalitions alliances and superalliances 10.1. Introduction 7.7. How are conflicts avoided and resolved? 10.2. What is meant by communication? 7.8. Human societies 10.3. Signal types in relation to the dominant senses 7.8.1. Despotism or egalitarianism? 10.4. Signal transmission and environmental 7.8.2. How do human societies function? conditions: acoustic signals in birds and 7.8.3. The social intelligence hypothesis mammals 10.5. The cost of signals Chapter 8. Altruistic behavior 10.6. The origin and evolution of signals 10.7. The conflict of interests between actors and 8.1. Introduction receivers: an arms race 8.2. How may the existence of altruism be 10.8. Honest communication and deceptive explained? communication 8.2.1. Kin selection 10.9. Complex communication in animals 8.2.2. Reciprocity: general features and direct 10.10. Human language reciprocity 10.10.1. Is there anything resembling human 8.2.3. Group selection language among other animals? 8.3. The importance of social punishment in the 10.10.2. The origin and evolution of human evolution of altruistic behavior language 8.4. Altruism in eusocial insects 10.10.3. Might some animals possess a poorly 8.4.1. Evolution of eusociality developed language? 8.4.2. Conflict in eusocial insects 8.5. Human altruism Chapter 11. The animal mind 8.5.1. The application of general models to human altruism 11.1. Introduction 8.5.2. Differentiating characteristics of human 11.2. Cognition altruism 11.2.1. The capacity for solving new problems 8.5.3. Factors that favor human altruistic 11.2.2. The capacity for future planning behavior 11.3. Making and using tools 8.5.4. Reinforced reciprocity 11.4. Culture 8.5.5. Group selection in humans 11.5. Consciousness and self-awareness 8.5.6. Is human behavior genuinely altruistic? 11.6. Awareness of shared consciousness 11.7. Emotions Chapter 9. Interspecific relationships 11.8. The sense of justice 11.9. Morality and religion 9.1. Introduction 9.2. The relationship between a plant and its References principal pollinator: coevolution 5 FOREWORD According to a Gallup poll taken in 2009 on the reproductive benefit of this characteristic. Manolo birthday of Charles Darwin, fewer than 40 percent Soler and his colleagues have developed several of my fellow Americans accept the reality of such ideas based on a Darwinian foundation. They evolution. The situation in Spain is somewhat have then evaluated each possible adaptive similar, although here slightly more than 60 function of this strange behavior using each percent of the population “believes in” evolution. hypothesis to produce testable predictions. The Of course, this means that more than 30 percent of research team has subsequently hunted for the all Spaniards do not think that evolution by natural evidence for or against the predictions they have in selection has occurred, and even this is a hand and in this manner, they reached the discouraging figure. conclusion that the males were demonstrating their Moreover, many of those in Spain and the physical condition (a trait related to their capacity United States who say that they believe in to bring food eventually to their nestlings). The evolution do not really have a sufficient females use the information they receive about understanding of Darwinian theory, much less an male parental quality to adjust their reproductive appreciation of the way in which modern investment in eggs. Thus the rock-carrying males biologists use the theory to conduct their research. benefit by getting more eggs to fertilize if they can Manolo Soler has recognized this reality, a point demonstrate that they are able to fully provision that led him to write this magnificent book to help their youngsters when these hatch from the eggs in members of the general public to advance their a nest. Without an evolutionary foundation, the comprehension of a scientific concept of great biologists involved and the rest of us would have importance. Dr. Soler is perfectly suited to not understood why male black wheatears behave undertake this task because he has utilized the way they do. Darwinian theory as a foundation for his elegant The same applies to many other puzzles studies of animal behavior. He is part of a group of explored in the pages of this book. Why do so Spanish ornithologists who have experienced great many animals reproduce sexually instead of success in their investigations of the adaptive value asexually? Why are the eggs of any number of bird of bird behavior. As a result, Dr. Soler has the species bright blue? Why do females and males of necessary background with which to explain the many species that appear to be monogamous value of evolutionary theory for scientific research. actually mate on the side with their neighbors? As Dr. Soler explains, Darwinian theory has Why are altruistic acts extremely rare in the natural two components. One part is the theory of natural world? Manolo Soler presents the most recent selection, which helps provide a way for biologists scientific answers to these questions and many to identify the adaptive value or function of the more. characteristics of living things that interest them. The author also demonstrates the utility, By “function”, we scientists know, thanks to indeed the necessity, of an evolutionary focus if Darwin, that we are talking about the role the trait we are going to really understand the behavior of plays in enabling individuals to reproduce human beings.