Evo Psych Lecture 2

Big Question #2: What is evolution?Evolution simply means “change over time”, or when more directly applied to living organisms it means “decent with modification.”

• Big Question #3: Where did the idea of evolution come from?

Evolutionary ideas have been around for millennia

• Anaximander, Greek philosopher (c. 610 BC – c. 546 BC) “in water the first animal arose covered with spiny skin and with the lapse of time some crawled onto dry land…” On Nature

Evolutionary ideas: Pre-Darwin

Augustine of Hippo (St. Augustine 354-430 CE) “In the beginning were created only germs or

causes of the forms of life which were afterwards to be developed in gradual course”St. Augustine from De Genesi ad Litteram (Literal meaning of Genesis)

Rationes Seminales: Seminal reasons, seminal ideas, originating principles. Presumed to have been implanted in organisms in seedlike form at the moment of creation. Some things were not created “fully formed” but were created more as seeds with the forms imprinted in them. Over time the seed is allowed to unfold, following the plan to it final form

Rationes Seminales

What’s evolutionary about it?Does allow for gradual change over time, with sometimes dramatic transformation taking place. Such as acorn transforming into oak tree. Furthermore, these transformations follow the laws of nature and require no divine intervention once the process has begun . De Genesi ad Litteram 9:17 (Augustine’s discussion of the regularity of natural laws)

What’s not evolutionary about it?Augustine adhered to the Aristotelian notion of fixity of species. Thus, the rationes seminales did not allow for the creation of new species, a central element of modern evolutionary theory. However, in his adherence to the notion of fixity of species Augustine was simply reflecting the state of knowledge of his day. De Genesi ad Litteram 9:17

Evolutionary Ideas: Pre-Darwin

Thomas Aquinas 1225-1274Adhered to Aristotelian fixity of speciesIntroduced a strong element of naturalism is

the understanding of human nature. Asserting that

• The human body is composed of the same elements of as other “inferior” creatures, thus sharing a material continuity with other organisms of the earth (ST P1 Q91 A1)

• Man is unquestionably categorized as an “animal” -- “man and ass are both in the genus animal” (from De principiis naturae, On the principles of nature).

Aquinas continued

• The human soul (or mind) is intimately connected to the body and the material state of the body affects the function of the soul or mind “because some men have bodies of better disposition, their souls have greater power of understanding” a strongly anti-dualist position contra Decartes (ST P1 Q85 A7)

• Marriage is a natural to humans and based on parental investment. Aquinas observes that in creatures where rearing of the young does not require provisioning by the male, the male leaves immediately after the sex act. In animals where provisioning is necessary males remain with the female for the purpose of rearing the young. As is true with birds, so it is with man. It is natural for man to remain with one woman for a long time, rather that short for the raising of children. (SCG B3 A122)

• He further asserts that marriage is natural to man for purposes of ensuring paternity certainty (SCG B3 A123)

• He argues against incest and polygamy not from divine law, but natural law arguing that incest goes contrary to man’s natural inclination to widen the circle of friendships in human society, and polygamy causes discord within the household , i.e. resource competition (SCG B3 A124-125).

©John Wiley & Sons, Inc. 2007 Huffman: Psychology in Action (8e)

Thomas Aquinas on Marriage

• We observe that in those animals, dogs for instance, in which the female herself suffices for the rearing of the offspring, the male and female stay no time together after the sexual act. But in animals in which the female herself does not suffice for the rearing of the offspring, male and female dwell together after the sexual act so long as is necessary for the rearing and training of the offspring. This appears in birds whose young are incapable of their own food after they are hatched…Hence, whereas it is necessary in all animals for the male to stand by the female for such a time as the father’s concurrence is requisite for bringing up the progeny, it is natural for man to be tied to…one woman for a long period…(SCG B3 Q122).

Evolutionary Ideas: Pre-Darwin

• Georges de Buffon 1707-1788French naturalist, mathematician,

cosmologistIn his Histoire naturelle discusses a

concept similar to “common descent.” However, did not see a close relationship between humans and apes. Credited by Darwin as being the first modern author to treat evolution in a scientific spirit.

Darwinism

• Charles Darwin’s major contribution was not evolution itself; but the mechanism by which it operated: Natural selection

• NS was also discussed by Darwin’s contemporary: Alfred Russel Wallace

Evolution: Basic Principles

Evolution: Change over time; decent with modificationNatural Selection: Primary mechanism producing

evolution (change over time). There are other mechanisms such as: sexual selection, social selection, drift.

Basic principles of NS:1. Variability: stuff varies2. Heritability: variation is passed on genetically3. Competition: limited resources4. Selection: some variations are advantageous in

securing limited resources and tend to passed on more than others = change over time

Spencer’s misleading summary of NS: “survival of the fittest.”

History of Evolutionary Psychology

Emergence of Psychology as science: 1879Wilhelm Wundt’s StructuralismWilliam James: FunctionalismJohn Watson: BehaviorismOnly James saw evolution as relevantBehaviorism (equipotentiality vs. prepared learning)

European Ethology

Study of animal behaviorNiko Tinbergen; Konrad Lorenz; Karl Von FrischRelevance of evolution, important conceptsKinship; altruism; imitation; aggression; functional

and adaptive significance of behavior

E. O. Wilson and Sociobiology

• In 1975 Harvard biologist E. O. Wilson published Sociobiology

• Integrating evolution into the study of animal behavior, especially social behavior

• Proposed extending the study to human behavior

• Controversial – genetic determinism

Evo Psych and Sociobio

• Tooby and Cosmides Adapted Mind, 1992 (mental modules for solving past adaptive problems)

• David Buss: Mating Universals