Human Evolutionary Psychology

Preface xi
Acknowledgements xii
1. The Evolutionary Approach to Human Behaviour 1
Natural selection 3
Box 1.1 Speciation and the evolutionary processes 4
Asking the right questions 5
Box 1.2 Reductionism vs holism 7
Approaches to the study of human behaviour 8
Box 1.3 The problem of external validity 11
Box 1.4 Human evolution 13
Towards a unified approach 14
Box 1.5 Modern human origins 16
Chapter summary 21
Further reading 21
2. Basics of Evolutionary Theory 22
Individual selection and the selfish gene 22
Box 2.1 Genomic imprinting 24
The problem of altruism 25
Box 2.2 Calculating degrees of relatedness 28
Box 2.3 Prisoner's dilemma 31
Box 2.4 Other models of cooperation 32
Box 2.5 Evolutionarily stable strategies 33
Parental investment and parent-offspring conflict 34
Sexual selection 37
Box 2.6 Female choice for exaggerated male traits 40
Box 2.7 Why do handicaps have to be so costly? 42
Chapter summary 44
Further reading 44
3. Cooperation Among Kin 45
Kin selection in humans 45
Box 3.1 Rules of thumb and kin recognition 48
Box 3.2 Adoption: an exception to kin selection? 50
Reproductive value and kin selection 52
Box 3.3 Reproductive value 53
Kinship, homicide and child abuse 56
Box 3.4 Homicide and infanticide as 'conflict assays' 59
Kinship and contingency 61
Kinship and health 64
Chapter summary 66
Further reading 66
4. Reciprocity and Sharing 67
Cooperation in humans: a difference in degree or kind? 67
Box 4.1 Fairness 69
Reciprocity and information exchange 69
Box 4.2 Competitive altruism 71
Labour exchange and bet hedging 72
Food sharing among hunter-gatherers 72
Box 4.3 The marginal value theorem and tolerated theft 77
Box 4.4 The tragedy of the commons 85
Are humans inherently selfish? 86
Box 4.5 How 'selfish' genes lead to non-selfish people 90
Chapter summary 91
Further reading 92
5. Mate Choice and Sexual Selection 93
Universal principles of mate choice 94
Box 5.1 Anisogamy 95
Box 5.2 Lonely hearts advertisements: methodological considerations 97
Box 5.3 Evolution of pairbonding 104
Sexually selected traits 105
Box 5.4 WHR and body mass index 109
Box 5.5 The problem of concealed ovulation 112
Conditional mate choice strategies 118
Courtship 122
Fitness consequences of mate choice 126
Box 5.6 Changes in bridewealth among the Kipsigis 128
Chapter summary 136
Further reading 136
6. Life-history Constraints and Reproductive Decisions 137
Optimising family size 137
Box 6.1 Why do humans have such large brains? 139
Box 6.2 Why are human babies born so early? 141
Box 6.3 Impact of offspring production on parental survival 143
Box 6.4 Optimality models and stochastic dynamic programming 146
Box 6.5 Are !Kung birth rates low by accident rather than design? 148
Scheduling reproduction 150
For love or money 154
The demographic transition 158
The evolution of menopause 164
Box 6.6 Phenotypic correlations 165
Box 6.7 Celibacy and homosexuality 168
Chapter summary 169
Further reading 170
7. Parental Investment Strategies 171
Conflict in the womb 171
Parental biases and sibling rivalry 172
Box 7.1 Pregnancy sickness and parent-offspring conflict 173
Box 7.2 Teaching biases and peer groups 175
Box 7.3 Family environment and future reproductive strategies 176
Infanticide: scheduling investment 178
Box 7.4 Paternity certainty and sexual jealousy 182
Selective infanticide and the sex ratio 188
Box 7.5 Testing the Trivers-Willard hypothesis 192
Condition-dependent investment strategies 194
Chapter summary 202
Further reading 202
8. Marriage and Inheritance 203
Matrilineal vs patrilineal inheritance 204
Box 8.1 Marriage and inheritance: a phylogenetic analysis 205
Box 8.2 Environmental correlates of polygyny 206
Resource competition and lineage survival 209
Box 8.3 Wealth-dependent herd management 213
Keeping it in the family: incest