Week 8
# Super Detailed Notes on Lectures 8.1 (Love & Attraction) and 8.3 (Individual Differences)
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## Lecture 8.1: What is Love? Evolutionary and Psychological Perspectives
### Key Themes:
1. Defining Love
- Subjective and multifaceted (e.g., connection, safety, bonding, reproduction).
- Evolutionary perspective: Love is a behavior evolved to maximize gene survival.
2. Attraction and Beauty
- Cultural vs. Biological Determinants:
- Cultural: Esther Honig’s "Make Me Beautiful" experiment showed Photoshop artists from different cultures altered her image based on local beauty standards.
- Biological: Universal traits like symmetry, averageness, and neoteny (retention of juvenile features) are cross-culturally attractive.
- Symmetry:
- Indicator of health (asymmetry may signal disease/parasites during development).
- Supported by studies like Rikowski & Grammer (1999) where body odor preferences correlated with symmetry.
- Averageness:
- Averaged faces are perceived as more attractive (Galton’s composite portraits).
- "Cheerleader Effect": Groups appear more attractive because brains average faces.
- Neoteny:
- Features like large eyes, small chin (e.g., Disney characters) signal youth and fertility.
- Evolutionary explanation: Younger mates = higher reproductive potential.
3. Evolutionary Psychology of Love
- Mate Selection:
- Females may prefer males with high testosterone (wide jaws) during peak fertility but nurturing males otherwise.
- Males may prefer youthful features linked to fertility.
- Critiques:
- Heteronormative assumptions; ignores LGBTQ+ relationships.
- Overemphasis on reproduction; neglects emotional/companionate love.
4. Case Study: Grandmother Hypothesis
- People often prefer maternal grandmothers over paternal ones.
- Evolutionary explanation: Maternal grandmothers have higher genetic certainty (mother’s paternity is unambiguous).
- Alternative explanations:
- Proximity (maternal grandmothers may live closer).
- Emotional bonding (mother-daughter relationships are stronger).
5. Cautionary Tales in Evolutionary Psychology
- Kakapo Parrot: Maladapted to new predators (stoats) due to evolved traits (freezing response) that were beneficial in its original environment.
- Rat Pup Behavior: Wriggling to find nipples seems innate but is learned via one-trial conditioning (squeezing in birth canal + smell association).
- Three-Eyed Frog Experiment: Ocular dominance columns (brain structures for 3D vision) emerged in frogs with surgically altered forward-facing eyes, showing neural plasticity, not hardwired genes.
- Limitations:
- Evolutionary explanations often conflate correlation with causation.
- Ignore cultural/social influences (e.g., testosterone drops in new fathers may be due to sleep deprivation, not evolved caregiving).
6. The "Gay Gene" Debate
- No evidence for a "gene for heterosexuality" despite its evolutionary advantage.
- Homosexuality is widespread in nature (e.g., 90% of giraffe mating is male-male).
- Suggests genes encode plasticity, not fixed behaviors.
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## Lecture 8.3: What Makes Us Different? Personality and Intelligence
### Key Themes:
1. Measuring Individual Differences
- Projective Tests (Rorschach Inkblot):
- Discredited as diagnostic tools; reveal more about the therapist’s biases than the patient.
- Theory-Driven Tests (Myers-Briggs):
- Based on Jungian typology (e.g., INTJ).
- Criticisms:
- Dichotomous categories ignore normal distributions.
- Low test-retest reliability (~50% get different results weeks later).
- Empirical Approaches (Big Five/OCEAN):
- Derived from factor analysis of behavioral data.
- Traits:
1. Openness (creativity, curiosity).
2. Conscientiousness (organization, self-discipline).
3. Extraversion (sociability, enthusiasm).
4. Agreeableness (compassion, cooperation).
5. Neuroticism (emotional instability).
- Predictive validity:
- Extraverts use words like "party"; introverts sigh more in texts.
- Conscientiousness correlates with cleaner shoes.
2. Intelligence Testing
- Stanford-Binet IQ Test:
- Early focus on mental age (e.g., "What’s foolish about claiming to find Columbus’s childhood skull?").
- Cultural bias (e.g., assumes knowledge of Western history).
- Multiple Intelligences (Gardner):
- Linguistic, musical, logical-mathematical, etc.
- General Intelligence (Spearman’s g):
- Statistically, IQ subtests correlate; g explains shared variance.
- Raven’s Matrices:
- Culture-fair measure of fluid intelligence (pattern recognition).
3. Nature vs. Nurture: Heritability
- Definition: Proportion of trait variance in a population due to genetic differences (e.g., height = 0.9, IQ = ~0.5–0.8).
- Misconceptions:
- Not "80% of your IQ is from genes."
- Not "Group differences (e.g., race/class) are genetic."
- Key Insight: Heritability depends on environment.
- Example: In a world where everyone smokes, lung cancer heritability rises because environment is constant.
- Gene-Environment Interaction:
- Flynn Effect: IQ scores rise over decades (due to nutrition, education, etc.), showing environmental impact.
- Shared Environment: Friends are genetically similar to 4th cousins (homophily).
4. Political and Ethical Implications
- Eugenics History:
- Goddard’s (1912) Kallikak Family falsely claimed "feeble-mindedness" was hereditary.
- Used to justify segregation/immigration laws.
- Modern Genetics:
- No "gay gene" or "IQ gene" found; traits are polygenic + environmentally mediated.
- Ethical dilemmas: Should we select embryos based on genetic potential?
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### Critical Takeaways:
- Love/Attraction: Evolutionary theories explain some patterns but oversimplify human diversity.
- Personality: Big Five is robust; Myers-Briggs is pop psychology.
- Intelligence: g exists but is not destiny—environment matters.
- Heritability: Misused to justify inequality; it describes variance within groups, not between them.
- Caution: Evolutionary psychology risks "just-so stories"; genes interact with culture/development.
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Final Note: These lectures emphasize critical thinking—question assumptions, distinguish causation from correlation, and recognize the limits of biological determinism.
# Detailed Lecture Notes: Lecture 8.2 – What Makes Us Special?
## Introduction
- Key Question: How does the evolutionary history of our species explain modern behavior?
- Focus Areas:
- Behaviors evolution can explain.
- Insights into our evolutionary past.
- Cautionary tales about evolutionary explanations.
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## Cautionary Tales
1. Baby-Killing Cavemen: Evolutionary explanations for infanticide (e.g., stepfathers vs. biological fathers).
2. Wriggling Rat Pups: Learned behavior during birth, not hardwired.
3. Three-Eyed Frog: Ocular dominance columns develop based on environmental input, not innate genes.
4. Girls Who Like Boys Who Like Girls: Sexual preference as an interaction of innate dispositions, learning, and social structure (Bem’s Exotic Becomes Erotic theory).
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## The Kakapo: A Case Study in Evolutionary Mismatch
- Unique Traits:
- World’s only flightless parrot.
- Lek mating system (males build basins and emit low-frequency booms).
- 30-day hatching, strong odor.
- Only 86 alive today (critically endangered).
- Evolutionary Mismatch:
- Adapted to a densely forested New Zealand with abundant fruit trees.
- Deforestation and introduced predators (stoats, weasels) disrupted its survival strategies.
- Lesson: Traits optimized for past environments may be maladaptive in rapidly changing ones.
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## Evolutionary Psychology
- Definition: Analyzing human behavior through evolutionary adaptations.
- Key Ideas:
- Atavistic Cognitive Quirks: Traits adaptive in ancestral environments but not necessarily today (e.g., disgust responses, social cheating detection).
- Human Uniqueness Claims: Often overstated when compared to other species.
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## What Makes Humans "Special"?
### 1. Global Dominance?
- Humans populate the entire planet, but:
- Bacteria are the most abundant life form.
- Insects and nematodes dominate in numbers.
### 2. Farming?
- Humans farm plants and animals, but:
- Leafcutter ants farm fungus.
- Wood ants "herd" aphids for secretions.
### 3. Technology?
- Humans invented the wheel, but:
- Bacterial flagella function as rotary engines.
### 4. Weapons?
- Humans have advanced weapons, but:
- Bombardier beetles eject explosive 100°C fluid.
### 5. Art?
- Humans create art, but:
- Bowerbirds construct elaborate, aesthetically arranged displays to attract mates.
### 6. Intelligence?
- Human Strengths:
- Problem-solving, tool use, working memory, symbolic reasoning.
- Animal Counterexamples:
- Chimps outperform humans in short-term visual memory tasks.
- Chimps solve novel problems (e.g., using water displacement to retrieve peanuts).
- Douglas Adams’ Quote:
- Humans assume they’re smarter than dolphins because of technology, but dolphins might think the same for opposite reasons.
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## The Great Leap Forward (~40,000 Years Ago)
- Sudden Advancements:
- Proliferation of tools (needles, fishing hooks, arrowheads).
- Cave art, symbolic representation, jewelry.
- Possible Causes:
- Not Brain Size: Neanderthals had larger brains.
- Not Tool Use: Tools existed for millions of years.
- Language Hypothesis:
- Lowering of the hyoid bone enabled complex vocalizations.
- May have triggered cultural and technological explosion.
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## Evolution and Decision-Making
### 1. Disgust and Social Conservatism (Paul Rozin & David Buss)
- Evolved Disgust Mechanism:
- Originally avoided disease (rotting food, bodily fluids).
- Now extends to moral judgments (e.g., associating "evil" with contamination).
- Political Exploitation:
- Linking disgust to social issues (e.g., anti-gay marriage campaigns using foul smells).
### 2. Cheater Detection (Cosmides & Tooby)
- Wason Selection Task:
- Abstract Version: Poor performance (20% correct).
- Social Cheating Version: High performance (75% correct).
- Evolutionary Explanation:
- Humans evolved a "cheater detection module" for reciprocal altruism.
- Explains outrage over social violations (e.g., queue-jumping).
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## Challenges to Simple Evolutionary Psychology
1. Gene-Environment Interaction:
- Traits develop from interactions, not just genes (e.g., ocular dominance columns in the three-eyed frog).
2. Overemphasis on "Cavemen" Hypotheses:
- Social explanations (modern stressors) may suffice without invoking ancestral environments.
3. No "Gay Gene":
- Bem’s Exotic Becomes Erotic Theory:
- Childhood gender nonconformity → play with opposite-sex peers → unfamiliarity → sexual attraction.
- Explains both heterosexuality and homosexuality via social learning.
4. Culture Shapes Evolution:
- Humans uniquely shape their environment, making simple evolutionary explanations insufficient.
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## Key Takeaways
- Avoid Anthropomorphic Bias: Humans are not the "pinnacle" of evolution.
- Evolutionary Mismatch: Traits optimized for past environments may not fit modern ones.
- Complex Interactions: Genes, environment, and culture interact in ways that defy simple evolutionary stories.
- Critical Thinking Needed: Evolutionary explanations should be evidence-based, not just speculative.
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## Further Questions
- How much of human behavior is truly "hardwired" vs. culturally shaped?
- What other species challenge our assumptions about intelligence and uniqueness?
- How does language bridge the gap between biology and culture?
End of Notes.