Introduction to Evolutionary Psychology Spring 2021 Dr Chapman

Introduction to Evolutionary Psychology Spring 2021 Dr Chapman 1

What is Evolution? Non-Biological Evolution: A process in which non-organic things (rocks for example) change into a different form (such as sand). Biological Evolution: Change in characteristics of a population over successive generations which means all life has a history and all life is related. Cultural Evolution: o o o describes how cultural changes overtime some would include this as part of non-biological evolution but in reality it is part of biological evolution, why? Caution: Do not confuse with Development which is biological and psychological change in an individual during their lifetime. 2

History of Evolutionary Theory Pre-Darwin o o o Charles Darwin (1809 – 1882) o the codeveloper of theory of evolution Travels in the Amazon and Malay Archipelago (1848 -1862) Neo-Darwinism: modifications to Darwin's theory On the Origin of Species by Means of Natural Selection (1859) remains one of the most influential books ever written. Descent with Modification: (Evolution) Descent implies common ancestry and modification implies change in gene frequency of a population across generations. Alfred Russel Wallace(1823 - 1913) Aristotle (384 BC – 322 BC) The History of Animals, to discover the secrets of nature’s patterns as gradation in nature, his scala naturae. Carl Linnaeus categorized all known species of his time (1753) Erasmus Darwin in the late 1700's, proposed that life had changed over time. Jean Baptiste de Lamarck proposed the inheritance of acquired characteristics to explain, among other things, the length of the giraffe neck. Based on a more complete understanding of genetics The modern synthesis (see below) A more detailed history of evolutionary history 3

Darwin's Influence on Modern Thought Ernst Mayr, Scientific American July 2000, p. 79 -83 In the same pantheon as Karl Marx, Sigmund Freud and Albert Einstein (so is Ernst Mayer) His ideas where the foundation for Many of Darwin's ideas conflicted with what was assumed to be true Evolutionary Biology as an historical approach to biology Philosophy of Biology Theories are largely based on concepts not rules or laws Theory of common descent proclaims humans to be animals Darwinism rejects all supernatural phenomena and causations rejects typology, or essentialism and instead embraces "endless variation" makes teleology unnecessary, there is no goal directed "progress" in Biology does away with determinism because generation of variation is based on aspects of randomness and chance 4

Darwin's Theory of Natural Selection: nature selects individuals whom survive and reproduce the process by which some organisms live and reproduce while others die before reproducing because of three factors Inheritance (common descent) transmission of genetic from parents to offspring Variation in genotype producing variation in phenotypic traits Selection by the environment 5

Darwin's Theory of Natural Selection The Struggle for Existence could be a literal struggle for survival but is used as a metaphorical illustration of natural selection see Table 1 "The Great Struggles of Life" Malthus: size of population can exceed carrying capacity of the environment because of population growth struggles with the natural conditions of life such as weather and climate, food shortages, falls from trees or cliffs, drowning, and natural disasters such as earthquakes struggles with other species such as microorganisms, insects, snakes, predator - prey relationships, struggles with members of one’s own species because of competition for territory, food, water which can result in warfare 6

Darwin's Theory of Sexual Selection Same as natural selection except it only applies to attributes that improve an organism's ability to reproduce The Struggle for Mates Intrasexual (same-sex) competition: male-male: males compete for access to females Darwin mostly focused on male-male competition common reason for male-male fighting female-female: females compete for access to males more important in humans then most mammals common reason for female-female fighting Intersexual selection: mate preference female choice: females choose males based upon appearance or behaviors Darwin mostly focused on female choice. male choice: males choose females based upon appearance or behaviors Recent research includes more coverage of male choice 7

The Role of Natural and Sexual Selection • "Second, Evolution by natural selection is not forward looking and is not "intentional". Buss textbook p 9 – Organisms evolve across generations to fit their environment – Individuals with traits that enhance their survival and reproduction produce more offspring i. e. giraffe with a long neck • "Another critical feature of selection is that it is gradual, at least when evaluated relative to human life span" Buss textbook p 9 – Most changes to traits occur across many generations – Changes to genes for these traits change through mutation • Many different genes responsible for length of giraffe neck – Some traits require fewer generations then others to change • for example genes related to development which can influence the size of the brain, more on this later. 8

Causes of "biological" evolutionary change • "First, Natural selection and sexual selection are not the only causes of evolutionary change. " Buss textbook p 9 • Forces that increase variation of genotype – A. Mutations are a structural alteration in DNA. • from chance events during DNA replication. • can be caused by environmental insults such as radiation and mutagenic chemicals. • in multicellular organisms, mutations can be subdivided into – germline mutations, which can be passed on to progeny – somatic mutations, which cannot be transmitted to progeny. • can be either: – Neutral: are the most common type of mutation but have no effect on reproductive success; at least not under current environmental conditions. – Deleterious: are a less common type of mutation that reduces reproduce success and are decreased by selection processes. – Beneficial: are also a less common type of mutation that increase reproductive success and may be increased by selection process. But no guarantee that these variants will become fixed in the gene pool. – B. Recombination usually denotes a genetic event that occurs during the formation of sperm and egg cells and is also referred to as crossing over – C. Gene Flow (also known as migration) is the transfer of genes from one population to another. 9

Causes of "biological" evolutionary change • Forces that decrease variation of genotype – Natural and sexual selection are the primary cause of evolutionary change and the only known cause of adaptations. • Works to decrease variation – Genetic Drift: • A mechanism for evolutionary change resulting from the random fluctuations of gene frequencies from one generation to the next – especially in small populations • Founder Effect – when a small group breaks off from a larger population to found a new colony, they have a smaller gene pool – the genes of the smaller group may not be representative of those of the original population – the allele frequencies in subsequent generations may vary greatly from the allele frequencies of the original population. • Genetic Bottlenecks (population bottleneck) – when a population is drastically reduced in size » due to environmental events (such as famines, earthquakes, floods, fires, disease, or droughts) or human activities (such as genocide) – some genes may be lost from the gene pool as a result of chance What is the relationship between natural selection and other forces of change such as mutations or genetic drift? 10

The Modern Synthesis • Gregor Mendel (1822 – 1884) "father of modern genetics" for his study of the inheritance of traits in pea plants. • Ronald Fisher (1890 -1962) major contributions to Statistics, Evolutionary Biology and Genetics; a prominent eugenicist in the early part of his life. – Genes are the units of hereditary information composed of DNA that are carried on chromosomes. – Allele is any one of a number of viable DNA codings of the same gene occupying a given locus on a chromosome. – Genotype is the entire genetic identity of an individual, including alleles that do not show as outward characteristics. – Phenotype is the physical, clinical or biological characteristics of an organism, determined by the interaction of its genetic make-up with the environment. – Gene Pool of a species or a population is the complete set of unique alleles that would be found by inspecting the genetic material of every living member of that species or population. – Phylogeny is the origin and evolution of a set of organisms, usually a set of species. 11

The Ethology Movement • Ethology: Comparative study of the natural behavior of animal species – Douglas Spalding (1841 - 1877) – experiments on chickens demonstrated imprinting, published in Nature in 1872. – Oskar Heinroth (1871 – 1945) • first ethologist: comparative studies of avian (mostly water fowl) behavior • rediscovered imprinting • mentor to Konrad Lorenz – Karl von Frisch (1886 – 1982) • studied the sensory perceptions of the honey bee and was one of the first to explain the waggle dance. – Konrad Lorenz (1903 – 1989) • studied instinctive behavior such as imprinting – young duckling or gosling learn to follow the first conspicuous, moving object it sees within the first few days after hatching • Was part of the German National Socialist movement "Nazism" before and during WWII. 12

The Ethology Movement • Niko Tinbergen (1907 – 1988) – "The Study of Instinct" (1951) ideas on innate behavioural reactions in animals and the adaptiveness and evolutionary aspects of these behaviours. – Four Whys of behavior • 1. Function: how does the behaviour impact on the animal's chances of survival and reproduction? • 2. Causation: what are the stimuli that elicit the response, and how has it been modified by recent learning? • 3. Development: how does the behaviour change with age, and what early experiences are necessary for the behaviour to be shown? • 4. Evolution: how does the behaviour compare with similar behaviour in related species, and how might it have arisen through the process of phylogeny? • Lorenz, Frisch and Tinbergen were awarded the Nobel Prize in Physiology or Medicine in 1973 “for their discoveries concerning organization and elicitation of individual and social behaviour patterns” 13

The Inclusive Fitness Revolution • William D Hamilton (1936 - 2000) was a British evolutionary biologist, considered one of the greatest evolutionary theorists of the 20 th century. – classic fitness is the relative ability of an individual (or population) to survive and reproduce in a given environment. The 'fit' of an organism to its environment. – inclusive fitness is the expansion of the concept of the fitness of a genotype to include benefits accrued to relatives of an individual since relatives share parts of their genomes. • Robert Trivers's Theories – Reciprocal Altruism is an exchange of favors by two individuals in which one individual temporarily sacrifices potential fitness in expectation of a return. – Parental Investment is a theory in evolutionary models that describes parental behaviors that increase the probability that offspring will survive. – Parent-Offspring-Conflict which describes the inherent conflict between parent and offspring over resources. 14

The Sociobiology Controversy • Sociobiology – Based on early ethology, investigates social behaviors, such as mating patterns, territorial fights, pack hunting, and the hive society of social insects. – is the study of social animals, insects, bees, etc. , who are genetically programmed to create certain social structures. – Human Sociobiology, there may be genetic grounds for certain aspects of human behavior, that human society may not all be the result of just "learned" behavior. • Edward O. Wilson is an entomologist and biologist known for his work on ecology, evolution, and sociobiology. – Sociobiology: The New Synthesis, 1975 – established sociobiology as a new scientific field – Wilson used sociobiology and evolutionary principles to explain the behavior of social insects and then to understand the social behavior of other animals, including humans – All of his work is based on Williams, Hamilton, Trivers and the Modern Synthesis – Human sociobiology strongly apposed by left-wing "Marxist" politics and many social scientists 15

Founders of Evolutionary Psychology Leif Edward Ottesen Kennair in T. K. Shackelford, V. A. Weekes-Shackelford (eds. ), Encyclopedia of Evolutionary Psychological Science • Irv Devore (1934 – 2014) – Cosmides and Tooby were his students and he also supported the work of Daly and Wilson. • Donald Symons – 1979 book The Evolution of Human Sexuality • Martin Daly and Margo Wilson – Young Male Syndrome and Homicide (1985) • Leda Cosmides and John Tooby – 1992 book The Adapted Mind • David Buss – Foundations of Evolutionary Psychology 1989 – 2008 Evolutionary Psychology textbook 16

Evolutionary Psychology Evolutionary Theory in Psychology Darwin may be considered the first evolutionary psychologist “In the distant future. . . psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Much light will be thrown on the origin of man and history” (Darwin, 1859, p. 488). Evolutionary theory as an explanatory perspective has been embraced by some, accepted with caution by others and criticized by yet other Psychologist. See: Evolutionary Theory and Psychology: several articles that comment on the significance and influence of Darwin’s theory and of current views of evolution within contemporary psychology. Also see: Review of: Evolutionary Thought in Psychology Evolutionary Psychology uses an evolutionary biology approach to understand emotions, motivations, personality, behavior and cognition provides an integrative approach to these topics that can not be found in either social sciences or biology alone proposes that the brain is comprises of many functional mechanisms, called psychological adaptations or psychological mechanisms each psychological adaptation evolved through natural selection 17

Evolutionary Psychology Four Key Questions what causal processes shaped the mind (organization of the brain circuits)? what are the mechanisms that makeup the mind (nervous system mechanisms)? what are the functions of these mechanisms? how does environmental input interact with the design of the mind? Use of the concept "mind" does not refer to a nonphysical spiritual concept can be substituted generally for the common concept of information processing by brain circuits 18

Misunderstandings of Evolution • The Biopolitics of Heredity – Chapter 2. Evolution by Jonathan Marks in EXPLORATIONS: An Open Invitation To Biological Anthropology – Unlike Darwin’s Origin of Species(1859) his Descent of Man(1871) finally got around to people where he included Victorian prejudices of his age. – Herbert Spencer popularized “survival of the fittest, ” held that unfettered competition led to advancement in nature, and also in human history, and since the poor were losers in that struggle, anything that made their lives easier would go against the natural order. – Ernst Haeckel’s 1868 popularization of Darwinism, … he made non. Europeans into the missing links that connected his readers to the apes, and depicted them as ugly caricatures. 19

Misunderstandings of Evolution • Plasticity, Robustness, Development and Evolution by Patrick Bateson, Peter Gluckman, 2011. Chapter One – Separating developmental processes from evolutionary processes produces misunderstanding of how environmental factors integrate with genotype (genetics) of the individual. • An embryo develops into a individual set of phenotypic characteristics from genetic environment interaction. – Alternative usages of the same terminology by different academic disciplines produce misunderstandings in the literature. • such as nature & nurture – Misunderstandings from different perspectives taken academic disciplines by such as social science instead of biology raise different questions about the same characteristics – Focus on the current utility of a trait instead of the mechanisms that underlie that trait 20

Misunderstandings of Evolution • Objections to Darwin's theory of natural and sexual selection – He did not have an explanation for inheritance – If change to phenotypic traits is gradual how do the early forms provide any advantages? • for example early transition to wings – Religious objections because of the standard understanding that species are immutable and where all created by a deity • Biological VS Cultural Explanations – 1. Human Behavior Is Genetically Determined: • Yes it is, but not in the way most people think it is • Biological Determinism is often misrepresented as determining behavior • Cultural Determinism is just as important in determining behavior – 2. If It's Evolutionary, We Can't Change It: • humans can use knowledge to modify (to some extent) their environment and or behavior – avoid sexual overperception bias (see page 309) – 3. Current Mechanisms Are Optimally Designed: • A. evolutionary time lags reduce adaptiveness of traits because the environment changes; preference for sugar and fat (see page 70) • B. costs of adaptations may constrain the evolution of a trait; fear of snakes – Evolve traits with benefits that outweigh costs 21