I. Continuum of unlearned-learned behaviorsII. Characteristics of instinctual behaviorsIII. Experience and the development of instinctsIV. “Preparedness” conceptV. Components of instinctsVI. Instinctual behaviors and learned behaviorsI. Principle of natural selectionII. Ultimate and proximate explanationsIII. Sexual selectionIV. Mating systemsV. AltruismVI. Parental investment theoryVII. NeotanyDarwin (1859) Evolution by Natural SelectionNeo-Darwinism (Fisher, 1930): integration of genetics and Darwinian theory.Ethology (~1940 ): study of animal behavior in natural settings; instincts; adaptiveness of behavior.Sociobiology (~1970) & evolutionary psychology (~1980).Biological and genetic bases of human behavior, including social behavior. These two are alternatives to or rivals with the “standard social science model” with its emphasis on social and cultural (environmental) determination of behavior.Over time, the frequency of genes that benefit within an environment will increaseEx: moths on trees, color that matches with bark color will increasePossible biological theory:Evolutionary change works at the level of the individuals- does not function for the good of the speciesComplex molecules that comprise genes only want to make copies of themselvesFitness: reproductive success of an individual and genetically similar individualInclusive fitness: self-sacrifice for someone who carries your genesUltimate vs. Proximate Explanations:Ultimate: explanation at the evolutionary level;What function did this behavior have in promoting fitness? Not usually part of our immediate awareness (cognitively impenetrable)ProximateWhat are the immediate causes and specific mechanisms of the behavior in an individual?Easy to investigateAwareness, feelings- Example: Why do male songbirds sing?Ultimate explanation: singing serves to attract females and defend territory from other males; males were selected for singing over evolutionary time; singing contributed to fitnessProximate explanation: increased daylight in spring leads to increased testosterone production, activates a special brain center that controls singing; role of experience in song-learningAltruistic behavior:Contributes to your fitness in that your family shares genes with youImmediate causes are differentKin selection theory: work in the interest of preserving genes that he shares with close relatives (inclusive fitness)Reciprocity theory: those individuals who have helped you and do the same for themBird’s self-handicapping theory: (with peacocks) my tail slows me down, makes me a target, and is biologically expensive to grow and maintain, but I’m so good that it doesn’t matterAssortative mating vs. random matingPositive assortative mating: mating occurs between individuals who are similar with respect to heritable traitsPositive correlation: Physical (height), personality (introversion-extraversion), cognitive (education, mental ability), attitudinal (conservatism)Consequences: increases the genetic similarity of parents and offspring, increase genetic variation of trait in a population (compared to random assortment)Random Mating: no correlation between individuals who are matingNeotany: looking like a newbornWhy are babies cute?  cuteness triggers a releasing stimulus that triggers care-taking in organismsMickey Mouse sold more when he had the facial characteristics of a babyProblem with kittens – they eventually become cats; babies grow upJudgments of competence (due to “baby face”) are positively correlated with outcomes, esp. in elections – negative effectIn a given species, whichever sex manifests the greater parental investment:(1) will be the sex more competed for by members of the other sex for purposes of mating.(2) will also be the sex that is more discriminating in mating.Vestigial traits: no longer have their original function, but don’t reduce fitness.Side-effect traits: “To the best of anyone’s knowledge, the belly button serves no function related to survival or reproduction” p. 69.Chance-generated traits: “… the result of mutations that didn’t matter and therefore were never weeded out [or selected for] by natural selection.”Also: genetic drift , p. 69.Adaptation, on average: “ … came about in evolution because, on balance, they promoted survival and reproduction more often than they interfered … .“ p. 70.PSYC 100 1st Edition Lecture 6 Outline of Last Lecture  I. Continuum of unlearned-learned behaviors II. Characteristics of instinctual behaviorsIII. Experience and the development of instincts IV. “Preparedness” concept V. Components of instincts VI. Instinctual behaviors and learned behaviorsOutline of Current LectureI. Principle of natural selectionII. Ultimate and proximate explanationsIII. Sexual selectionIV. Mating systemsV. AltruismVI. Parental investment theoryVII. Neotany Current Lecture Darwin (1859) Evolution by Natural SelectionNeo-Darwinism (Fisher, 1930): integration of genetics and Darwinian theory. Ethology (~1940 ): study of animal behavior in natural settings; instincts; adaptiveness ofbehavior. Sociobiology (~1970) & evolutionary psychology (~1980). - Biological and genetic bases of human behavior, including social behavior. These two are alternatives to or rivals with the “standard social science model” with its emphasis on social and cultural (environmental) determination of behavior. Over time, the frequency of genes that benefit within an environment will increase- Ex: moths on trees, color that matches with bark color will increase Possible biological theory: Evolutionary change works at the level of the individuals- does not function for the good of the species - Complex molecules that comprise genes only want to make copies of themselves Fitness: reproductive success of an individual and genetically similar individual - Inclusive fitness: self-sacrifice for someone who carries your genes Ultimate vs. Proximate Explanations: Ultimate: explanation at the evolutionary level; - What function did this behavior have in promoting fitness? Not usually part of our immediate awareness (cognitively impenetrable)Proximate- What are the immediate causes and specific mechanisms of the behavior in an individual?- Easy to investigate- Awareness, feelings  - Example: Why do male songbirds sing?- Ultimate explanation: singing serves to attract females and defend territory from