Evolutionary Psychology

The New Science of the Mind

David M. Buss

• Publisher: Routledge
• Year: 2019
• ISBN:
  9780429590061
• Edition: 6
• Topic: Psychology
• Subtopic: Cognitive Psychology & Cognition
• Index: Psychology

Where did we come from?

What is our connection with other life forms?

What are the mechanisms of mind that define what it means to be a human being?

Evolutionary psychology is a revolutionary new science, a true synthesis of modern principles of psychology and evolutionary biology. Since the publication of the award-winning first edition of Evolutionary Psychology, there has been an explosion of research within the field. In this book, David M. Buss examines human behavior from an evolutionary perspective, providing students with the conceptual tools needed to study evolutionary psychology and apply them to empirical research on the human mind.

This edition contains expanded coverage of cultural evolution, with a new section on culture–gene co-evolution, additional studies discussing interbreeding between modern humans and Neanderthals, expanded discussions of evolutionary hypotheses that have been empirically disconfirmed, and much more!

Evolutionary Psychology features a wealth of student-friendly pedagogy including critical-thinking questions and case study boxes designed to show how to apply evolutionary psychology to real-life situations. It is an invaluable resource for undergraduates studying psychology, biology and anthropology.

See "Support Material" below for new online resources, including PowerPoint slides and Instructor's Manual and Test Bank.

Part 1
Foundations of Evolutionary Psychology

Two chapters introduce the foundations of evolutionary psychology. Chapter 1 traces the scientific movements leading to evolutionary psychology. First, we describe the landmarks in the history of evolutionary theory, starting with theories of evolution developed before Charles Darwin and ending with modern formulations of evolutionary theory widely accepted in the biological sciences today. Next, we examine three common misunderstandings about evolutionary theory. Finally, we trace landmarks in the field of psychology, starting with the influence Darwin had on the psychoanalytic theories of Sigmund Freud and ending with modern formulations of cognitive psychology.

Chapter 2 provides the conceptual foundations of modern evolutionary psychology and introduces the scientific tools used to test evolutionary psychological hypotheses. The first section examines theories about the origins of human nature. Then we turn to a definition of the core concept of an evolved psychological mechanism and outline the properties of these mechanisms. The middle portion of Chapter 2 describes the major methods used to test evolutionary psychological hypotheses and the sources of evidence on which these tests are based. Because the remainder of the book is organized around human adaptive problems, the end of Chapter 2 focuses on the tools evolutionary psychologists use to identify adaptive problems, starting with survival and ending with the problems of group living.

Chapter 1
The Scientific Movements Leading to Evolutionary Psychology

Learning Objectives

After studying this chapter, the reader will be able to:

• Identify the three essential ingredients of natural selection.
• Define particulate inheritance.
• List three common misunderstandings about evolutionary theory.
• Identify when Neanderthals went extinct.
• Explain why radical behaviorism went into scientific decline.

In the distant future I see open fields for more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.

—Charles Darwin (1859)

As the archeologist dusted off the dirt and debris from the skeleton, she noticed something strange: The left side of the skull had a large dent, apparently from a ferocious blow, and the rib cage—also on the left side—had the head of a spear lodged in it. Back in the laboratory, scientists determined that the skeleton was that of a Neanderthal man who had died roughly 50,000 years ago, the earliest known homicide victim. His killer, judging from the damage to the skull and rib cage, bore the lethal weapon in his right hand.

The fossil record of injuries to bones reveals two strikingly common patterns (Jurmain et al., 2009; Trinkaus & Zimmerman, 1982; Walker, 1995). First, the skeletons of men contain far more fractures and dents than do the skeletons of women. Second, the injuries are located mainly on the left frontal sides of the skulls and skeletons, suggesting mostly right-handed attackers. The bone record alone cannot tell us with certainty that combat among men was a central feature of human ancestral life. Nor can it tell us with certainty that men evolved to be the more physically aggressive sex. But skeletal remains provide clues that yield a fascinating piece of the puzzle of where we came from, the forces that shaped who we are, and the nature of our minds today.

The huge human brain, approximately 1,350 cubic centimeters, is the most complex organic structure in the known world. Understanding the human mind/brain mechanisms in evolutionary perspective is the goal of the new scientific discipline called evolutionary psychology. Evolutionary psychology focuses on four key questions: (1) Why is the mind designed the way it is—that is, what causal processes created, fashioned, or shaped the human mind into its current form? (2) How is the human mind designed—what are its mechanisms or component parts, and how are they organized? (3) What are the functions of the component parts and their organized structure—that is, what is the mind designed to do? (4) How does input from the current environment interact with the design of the human mind to produce observable behavior?

Contemplating the mysteries of the human mind is not new. Ancient Greeks such as Aristotle and Plato wrote manifestos on the subject. More recently, theories of the human mind such as the Freudian theory of psychoanalysis, the Skinnerian theory of reinforcement, and connectionism have vied for the attention of psychologists.

Only within the past few decades have we acquired the conceptual tools to synthesize our understanding of the human mind under one unifying theoretical framework—that of evolutionary psychology. This discipline pulls together findings from all disciplines of the mind, including those of brain imaging; learning and memory; attention, emotion, and passion; attraction, jealousy, and sex; self-esteem, status, and self-sacrifice; parenting, persuasion, and perception; kinship, warfare, and aggression; cooperation, altruism, and helping; ethics, morality, religion, and medicine; and commitment, culture, and consciousness. This book offers an introduction to evolutionary psychology and provides a road map to this new science of the mind.

This chapter starts by tracing the major landmarks in the history of evolutionary biology that were critical to the emergence of evolutionary psychology. Then we turn to the history of the field of psychology and show the progression of accomplishments that led to the need for integrating evolutionary theory with modern psychology.

Landmarks in the History of Evolutionary Thinking

We begin our examination of the history of evolutionary thinking well before the contributions of Charles Darwin and then consider the various milestones in its development through the end of the 20th century.

Evolution Before Darwin

Evolution refers to change over time. Change in life forms was postulated by scientists to have occurred long before Darwin published his classic 1859 book On the Origin of Species (see Glass, Temekin, & Straus, 1959; and Harris, 1992, for historical treatments).

Jean Baptiste Lamarck (1744–1829) was one of the first scientists to use the word biologie, which recognized the study of life as a distinct science. Lamarck believed in two major causes of species change: first, a natural tendency for each species to progress toward a higher form and, second, the inheritance of acquired characteristics. Lamarck proposed that animals must struggle to survive and this struggle causes their nerves to secrete a fluid that enlarges the organs involved in the struggle. Giraffes evolved long necks, he thought, through their attempts to eat from higher and higher leaves (recent evidence suggests that long necks may also play a role in mate competition through physical battles). Lamarck believed that the neck changes that came about from these strivings were passed down to succeeding generations of giraffes, hence the phrase “the inheritance of acquired characteristics.” Another theory of change in life forms was developed by Baron Georges Léopold Chrétien Frédérick Dagobert Cuvier (1769–1832). Cuvier proposed a theory called catastrophism, according to which species are extinguished periodically by sudden catastrophes, such as meteorites, and then replaced by different species.

Biologists before Darwin also noticed the bewildering variety of species, some with astonishing structural similarities. Humans, chimpanzees, and orangutans, for example, all have exactly five digits on each hand and foot. The wings of birds are similar to the flippers of seals, perhaps suggesting that one was modified from the other (Daly & Wilson, 1983). Comparisons among these species suggested that life was not static, as some scientists and theologians had argued. Further evidence suggesting change over time also came from the fossil record. Bones from older geological strata were not the same as bones from more recent geological strata. These bones would not be different, scientists reasoned, unless there had been a change in organic structure over time.

Another source of evidence came from comparing the embryological development of different species (Mayr, 1982). Biologists noticed that such development was strikingly similar in species that otherwise seemed very different from one another. An unusual loop-like pattern of arteries close to the bronchial slits characterizes the embryos of mammals, birds, and frogs. This evidence suggested, perhaps, that these species might have come from the same ancestors millions of years ago. All these pieces of evidence, present before 1859, suggested that life was not fixed or unchanging. The biologists who believed that life forms changed over time called themselves evolutionists.

Another key observation had been made by evolutionists before Darwin: Many species possess characteristics that seem to have a purpose. The porcupine’s quills help it fend off predators. The turtle’s shell helps to protect its tender organs from the hostile forces of nature. The beaks of many birds are designed to aid in cracking nuts. This apparent functionality, so abundant in nature, required an explanation.

Missing from the evolutionists’ accounts before Darwin, however, was a theory to explain how change might take place over time and how such seemingly purposeful structures such as the giraffe’s long neck and the porcupine’s sharp quills could have come about. A causal process to explain these biological phenomena was needed. Charles Darwin provided the theory of just such a process.

Darwin’s Theory of Natural Selection

Darwin’s task was more difficult than it might at first appear. He wanted not only to explain why change takes place over time in life forms but also to account for the particular ways it proceeds. He wanted to determine how new species emerge (hence the title of his book On the Origin of Species), as well as why others vanish or go extinct. Darwin wanted to explain why the component parts of animals—the long necks of giraffes, the wings of birds, and the trunks of elephants—existed in those particular forms. And he wanted to explain the apparent purposive quality of those forms, or why they seem to function to help organisms accomplish specific tasks.

The answers to these puzzles can be traced to a voyage Darwin took after graduating from Cambridge University. He traveled the world as a naturalist on a ship, the Beagle, for a 5-year period, from 1831 to 1836. During this voyage, he collected dozens of samples of birds and other animals from the Galápagos Islands in the Pacific Ocean. On returning from his voyage, he discovered that the Galápagos finches, which he had presumed were all of the same species, actually varied so much that they constituted different species. Indeed, each island in the Galápagos had a distinct species of finch. Darwin determined that these different finches had a common ancestor but had become different from each other because of the local ecological conditions on each island. This geographic variation was pivotal to Darwin’s conclusion that species are not immutable but can change over time.

What could account for why species change? Darwin struggled with several different theories of the origins of change but rejected all of them because they failed to explain a critical fact: the existence of adaptations. Darwin wanted to account for change, of course, but he also wanted to account for why organisms appeared so well designed for their local environments.

Charles Darwin created a scientific revolution in biology with his theory of natural selection. His book On the Origin of Species (1859) is packed with theoretical arguments and detailed empirical data that he amassed over the 25 years prior to the book’s publication.

It was… evident that [these other theories] could not account for the innumerable cases in which organisms of every kind are beautifully adapted to their habits of life—for instance, a woodpecker or tree-frog to climb trees, or a seed for dispersal by hooks and plumes. I had always been much struck by such adaptations, and until these could be explained it seemed to me almost useless to endeavour to prove by indirect evidence that species have been modified.

(Darwin, from his autobiography; cited in Ridley, 1996, p. 9)

Darwin unearthed a key to the puzzle of adaptations in Thomas Malthus’s An Essay on the Principle of Population (published in 1798), which introduced Darwin to the notion that organisms exist in numbers far greater than can survive and reproduce. The result must be a “struggle for existence,” in which favorable variations tend to be preserved and unfavorable ones tend to die out. When this process is repeated generation after generation, the end result is the formation of new adaptation.

More formally, Darwin’s answer to all these puzzles of life was the theory of natural selection and its three essential ingredients: variation, inheritance, and differential reproductive success.¹ First, organisms vary in all sorts of ways, such as in wing length, trunk strength, bone mass, cell structure, fighting ability, defensive ability, and social cunning. Variation is essential for the process of evolution to operate—it provides the “raw materials” for evolution. Second, only some of these variations are inherited—that is, passed down reliably from parents to their offspring, who then pass them on to their offspring down through the generations. Other variations, such as a wing deformity caused by an environmental accident, are not inherited by offspring. Only those variations that are inherited play a role in the evolutionary process....