Individual Differences: Evolutionary Psychology & Nature/Nurture Flashcards
What is the Nature-Nurture debate?
- The debate of “How much of an individual’s behaviour is due to their genotype and how much is due to their environment?”
What did Plato and Aristotle say about the Nature-Nurture debate?
Plato -> Nativism; Some knowledge and abilities are innate
Aristotle -> Philosophical empiricism; Knowledge is acquired only through experience
What is the “conclusion” of the Nature-Nurture debate?
A person’s behaviour is the product of both their genotype and environment. What is important for us to study is how they interact together to influence behaviour.
Explain the “Nature” side of the Nature-Nurture debate
- Traits are innate; Inherited from parents
- Formalised in Darwin’s theory of evolution via natural selection
- Combined with discovery of genetics to form the modern synthesis
What were the beliefs on evolution before Darwin?
- Species fixity; The idea that each species is fixed in their physical form which does not change over time
- Philosophers had always questioned this belief on the elements of nature and the origins of life
- Titus Lucretius Carus (99-55BC) wrote about natural selection -> “Individuals best suited to their environment would survive while others would be elimintated”
- Darwin then used the word evolution in his 1871 text, as the process of developing by gradual changes
Significant Precursors to Darwin (17th to 18th century): Pierre Maupertuis
- Suggested that particles from both mother and father are responsible for child’s attributes
- Nature side of the debate
Significant Precursors to Darwin (18th century): George-Louis Leclerc, Comte de Buffon
- Some considered him the father of evolutionism
- First to discuss a large number of evolutionary problems
- ex. origin of the Earth, issue of extinction, common ancestry, comparative anatomy, etc.
Significant Precursors to Darwin (18th century): Denis Diderot
- Speculated on the origins of life without divine intervention
- Presented ideas for survival by superior adaptation and was arrested and imprisoned for three months
What delayed Darwin’s work to be published?
- Darwin delayed the release of his essay on evolutionary ideas because of The Anti-Jacobin, a newspaper which also mocked Erasmus Darwin’ earlier work
- This satire would later be used to criticize and mock Charles Darwin
Significant Precursors to Darwin: Lamarck’s theories
- Lamarck’s theories of evolution were described in Philosophie zoologique (1809)
- Lamarckism is a theory of the inheritance of acquired traits (phenotypes)
- Attempted to explain how the environment in a current generation can impact heritability, and argued that the traits that develop in a person could be inherited by offspring
- Theory centres around use and disuse (The traits/characteristics/muscles that are used more during one’s lifetime are the ones that will be passed down to the next generation)
- Species would change over time because of a build up of these inherited changes
What inspired Darwin to study evolution?
- Travelled as an unpaid naturalist
- Found fossils of extinct species in Argentine
- Saw that living creatures are well-adjusted for living in their natural environment
- Set out to explain why species change and why those changes are so well-designed
Describe Darwin’s Journal of Researches (1845)
- Saw the importance of the environment and the struggle for existence in shaping adaptative responses
- Variation is not directed towards improved adaptation; evolution has no goal in mind -> It is undirected (selection pressures)
What did Darwin say about natural selection?
- Change in the form and behaviour of organisms within a population and between generations
- Change happens so slowly that it (usually) cannot be perceived
- Changes/variations in attributes occur most often through the random process of mutation
- If the attribute is an advantage to survival -> It is adaptative and is selected -> Passed onto next generation and increase in frequency
- If the attribute is disadvantageous to survival -> Survival chances of that individual is reduced -> Frequency decreases
What did Alfred Russel Wallace do in the study of evolution?
- Independently arrived at a similar idea to Darwin’s abstract, and sent a letter to Darwin
- However, Wallace did not think natural selection applied to human evolution, which he argued required divine intervention
What kind of response did Darwin’s work receive?
- Evolution was controversial but somewhat accepted by the scientific community
*Inspired William James (1980) to develop functionalism - But natural selection was criticised because it required a satisfactory theory of heredity
*Natural selection was said to have no supporting mechanism
*Darwin suggested pangenesis, and somewhat accepted Lamarckism
*August Weismann put forth strong arguments disproving pangenesis and Lamarckism, and put forward his theory of “germ plasm” inheritance
What were the key points in the study of evolution during the 20th century?
1909 - Wilhelm Johannsen coined the term “genes”
1913 - Thomas Hunt Morgan located the genes on the chromosomes (with which the infamous image of beads on a string emerged)
1930-32 - RA Fisher, JBS Haldene and S Wright independently published their own synthesis, showing that natural selection could operate with mendelian genetics
What were Gregor Mendel’s contributions to the study of evolution in the 19th century?
- Performed meticulous experiments and statistical analysis by cross-breeding variants of peas
- First to lay down the mathematics of genetics and heritability, and presented them in lectures
What were the key points of evolution studies, after Darwin?
- Dobzhansky’s influential works with fruit flies and Ford’s with moths
- 1942: Julian Huxley popularized the synthesis in Evolution
- 1942: Speciation by Ernst Mayr
- 1944: Simpson demonstrated that the fossil record was compatible with the synthesis
- 1947: Experts from all areas of biology gathered and came to the agreement that evolution occurs via natural selection and inheritance occurred via Mendelian principles
- In the 1970s: Lorenz & Titenbergen inspired the emergence of evolutionary psychology through their work on complex animal behaviours (spontaneous/natural, not learned)
What were the other key additions to the theory of evolution?
- Sexual selection
- Kin selection
- Group selection vs Selfish gene (Dawkins)
- Natural selection is not the only mechanism of evolution but it is the only mechanism for adaptation
- Dual-inheritance theory (gene-culture coevolution)