The Nature of Human Nature Evolutionary Psychology Spring 2019 Dr Chapman

1. The Nature of Human NatureEvolutionary PsychologySpring 2019Dr Chapman

2. Is There a Human Nature? • “Nature: the inherent character or basic constitution of a person or thing” • Merriam-Webster dictionary • All species have a nature, each molded by the evolutionary history of the species • a composite of the physical characteristics, behavior and environment they occupy • A lion nature • A wolf nature • A chimpanzee nature • “Nature: The phenomena of the physical world collectively, including plants, animals, the landscape, and other features and products of the earth, as opposed to humans or human creations.” • Oxford English dictionary • Humans should not be separated from nature • humans are animals so humans are part of nature • because humans produce cultural artifacts such as tools or buildings • some would exclude us from nature because we have culture • however birds build nests and chimpanzees make tools • Actually, culture is part of human nature

3. Human Universals • Evolutionary psychologists are identifying universal human nature, the evolved adaptations that collectively constitute universal human nature • Examples (do not need to know all these details, just a few examples) • anatomical: bipedalism, hands, big frontal cortex • behavioral: aggression, gestures, gossip, and facial expressions • mentally: emotions, dichotomous thinking, wariness around or fear of snakes, empathy • language: grammar, phonemes, polysemy, metonymy, antonyms, frequency and length of words • social: division of labor, social groups, age grading, the family, kinship systems, ethnocentrism, play, exchange, cooperation, and reciprocity • cultural: myths, legends, body adornment, daily routines, rules, concepts of luck and precedent, use and production of tools

4. Human Universals • Kinds of (do not need to know these details) • absolute universals: found among all peoples known to ethnography and history • near universals: some few known exceptions such as fire making • conditional universals: if a particular condition is met, then the trait in question always accompanies it such as calluses • statistical universals: at a rate that seems well above chance such as words used for the pupil of the eye • universal pools: a limited set of options exhaust the possible variations such as kinship terminologies

5. Human Universals • Causes of cultural universal such as myths • the evolution of the human mind (brain circuits) • cultural reflects the physical necessity of survival • the diffusion of useful ancient cultural traits • Role of culture • culture should not be separated from nature • culture such as the invention of tools is a product of human nature • cultural information is part of the environment that individuals live in so it acts as a selection factor

6. Human Universals • Cultural and Individual variability • Concept of Humans Universal does not imply that every person in every culture will have identical behavior • Interaction of cultural and biological influences produces a range of outcomes • At a general level there are similarities in human behavior • Humans have a preference for sweet • However, the specific food eaten will vary across culture • Strength of the preference will vary across individual

7. Three Products of Evolution (See Table 2.1) • Adaptations are traits that help living organisms survive in a particular environment. • By-Products are secondary or incidental traits that can be useful or may have no benefit. • Noise (random effects) produce changes in traits but are not selected

8. Noise • Random effects • result in changes in a phenotypic trait • are not selected for • are not connected to an adaptive trait • Mutations are the ultimate source of genetic variation so they are the ultimate source of phenotypic variation. • 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: • 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. • If they do become fixed then they are an adaptation • Accidents during development such as lack of nutrition or lack of experience that is needed for normal development. • "Sudden" changes in the environment

9. By-Products • Phenotypic traits that do not "currently" solve adaptive problem • They are carried along by adaptive traits so: • they were not selected for • do not have a functional design • Examples: • Belly Button is a by-product of placental birth • Red color of blood is a by-product of hemoglobin • High rates of abuse by stepparents is a by-product of a lack of parental solicitude.

10. Adaptations • Examples of adaptations • Morphological • drug resistance in bacteria • shape of a Finch's beaks • mane on a male lion • Behavioral • moving in large groups • retreat to shady locations during the hottest hours • aggression towards competitors • Cognitive/Emotional • perception of color • fear of snakes • language

11. Clarifying Adaptation and Natural Selection - 1 • George C. Williams (1926 – 2010) • Individual Selection • is selection for traits that would be beneficial to an individual. • Group Selection • is selection for traits that would be beneficial to a population at the expense of the individual possessing the trait. • An evolutionary process involving differential survival and reproduction of competing groups. • Adaptations • are the structures or behaviors of an organism that are suited to a particular environment. • the process of change to better conform with environmental conditions. • Adaptations are problem solving devices • They are the only known causal process by which complex, functional design can come to exist. • Evolved fear adaptations: Snakes and spiders, for example, signal potentially dangerous threats to survival.

12. Clarifying Adaptation and Natural Selection - 2 • "Inherited and reliably developing characteristic that came into existence through natural selection because it helped to solve a problem of survival or reproduction during the period of its evolution" (Buss p. 36) • Inherited: must have genes for the adaptations • Develop reliably among species members in normal environments • A product of natural or sexual selection • The design of adaptations reflects their functional efficiency • economy: does not waste energy • precision: specific to adaptive problem • reliability: occurs in most individuals in a population

13. Psychological Adaptations • Psychological Adaptations "evolved psychological mechanisms" Adaptive problems select for adaptations. Cosmides and Tooby 2005 p 9 • There are many adaptive problems (struggles) that are obstacles to survival or reproduction the presence of predators • the presence of pathogens • variance in the food supply • the vulnerability of infants • presence of family in one’s social group • finding fertile mates • Adaptive problems have two defining characteristics • environmental obstacles to survival that most individuals encountered across many generations • social relationships that are exploited to increase an individuals reproduction or the reproduction of its relatives. • Adaptations are retained or discarded by natural selection on the basis of how well they function as solutions to adaptive problems. • Psychological Adaptations are phenotypic traits as brain circuits

14. Psychological Adaptations • Brain Circuits as Adaptations for behavior and cognitive • adaptive behaviors promote survival and reproduction of individuals and their relatives • brain circuits that reliably produce adaptive behavior become incorporated into a species’ neural design • the brain is a physical system designed by natural selection • composed of many functionally specialized circuits • different neural circuits are specialized for solving different adaptive problems

15. Environment of Evolutionary Adaptedness (EEA) • Was coined by John Bowlby of attachment theory fame • EEA does not refer to a specific time or place • could be relatively recent such as evolution of human language circuits • or across a very long time span such as the structures of the eye • Composite of selection pressures during the adaptation's period of evolution • each adaptation has an EEA • EEA for language • EEA for sweet preference • EEA for stranger anxiety • some adaptations evolved to solve adaptive problems of our ancestors so they may not solve the adaptive problems of contemporary industrial society such as an abundance of food

16. Definition of Evolved Psychological Mechanisms • Psychological Mechanisms are adaptations, constructed by natural selection over evolutionary time • Form determined by solving a specific problem • Specialized Information Processing • Input identifies the adaptive problem • Decision rules transform the input into an output • Output can be physiological(emotional), behavioral and or cognitive • Output is directed toward the solution to the adaptive problem • Evolved Psychological Mechanisms 10 illustrations • Example of a Psychological Mechanism • Fear of snakes article by Vanessa LoBue and Judy S. DeLoache • A snake like object on the ground, identify the object as a snake, respond with fear, move away, appraise situation • “Snake” Sensory Perceptual Processing Decision  Output • Snake slithering through the grass You Tube video

17. Important Properties of Evolved Psychological Mechanisms • Problem specific psychological mechanisms: • adaptive problems are specific and require a specific mechanism to solve them • "no such thing as a general adaptive problem" • relatively easy to do for other body parts such as liver, heart, hand, eyes • dividing up the mind based on psychological functions is much more difficult • Nonarbitrarycriteria for identification and description of psychological mechanisms is derived from their function. • Function determines form so identifying function can help understand the form. • "Carving the Mind at It's Joints" • "Dividing the Mind by Its Functions" such as • Respiration • Fear response • Language production

18. General Purpose versus Domain Specific mechanisms • Domain-specific psychological mechanisms solves specific problem of survival or reproduction that was recurrent in the EEA. • Humans Possess many Evolved Psychological Mechanisms: • Fear based predator avoidance • Sweet preference for finding food • Numerous psychological mechanisms produces behavioral flexibility • Domain-general psychological mechanisms are aimed at solving complex, novel problems • Solving problems using rationality • Evolution of General Intelligence • useful in solving novel problems • better at attaining goals in unfamiliar and novel conditions • Superordinate mechanisms that regulate or coordinate a large number of other functions • General mechanisms of learning examples • Associative conditioning in classical conditioning • Role of reinforcement in instrumental conditioning

19. Brain circuits as Psychological Mechanisms • For cognitive scientists, brain and mind are terms that refer to two complementary aspects • either in terms of its physical properties (the brain circuits) • or in terms of its information-processing operation (the mind) • Brain circuits • "programs" that process and store information • Programs from computer metaphor of the brain/mind • Output signals to muscles and endocrine glands • Brain circuits are phenotypic traits • a brain circuit is a physical system • Selected to process information and generate behavior that is appropriate to environmental circumstances

20. Brain circuits as Psychological Mechanisms • Our neural circuits were designed by natural selection to solve problems such as • finding a mate • cooperating with others • hunting • gathering • protecting children • avoiding predators • all normal human minds reliably develop a standard collection of brain circuits • some "most?" are functionally specialized therefore domain-specific • other brain circuits are domain-general • circuits determine how the brain processes information • sensory circuits such as the retina of your eye • motor circuits send information from your brain to motor neurons to produce behavior • Motivational brain circuits that govern when and what you eat • Cognitive brain circuits for reasoning , decision making or learning

21. Design of the Human Mind • Organization of all of these brain circuits influenced by natural and sexual selection • This would be the unique set of "species-typical" information processing and behavior that is "human nature" • Culture is a huge part of human nature • culture information used by humans for survival and reproduction • this includes technology such as tools, norms, values and institutions • all of culture through out human history has been generated by human brain circuits • Specialized brain circuits related to culture • inventing technology • imitating others • theory of mind i.e. "mind reading" • generating norms and values