Genetics and Evolution Flashcards
genetics
Genetics refers to the study of inheritance and variation in organisms, focusing on how traits are passed from one generation to the next. In social psychology, genetics is often explored to understand how inherited traits influence behavior, cognition, and emotions.
Natural Selection (Darwin, 1859)
Natural Selection is the process by which traits that enhance survival and reproduction are passed on more frequently to future generations. Over time, these beneficial traits become more prevalent in the population.
Adaptations that enhance an organism’s ability to survive or reproduce increase the chances of those genes being passed on to offspring.
Kin Selection Theory (Hamilton, 1964)
Kin Selection is the idea that individuals are more likely to help their relatives because they share a portion of their genetic material. Helping kin increases the likelihood of shared genes being passed on to the next generation.
This is often described as the “inclusive fitness” of helping others who share your genes, even at a personal cost.
Reciprocal Altruism (Trivers, 1971)
Reciprocal Altruism suggests that individuals may help others with the expectation that the favor will be returned in the future, increasing the helper’s reproductive success. This theory explains cooperation between non-kin.
It is often described as “I’ll scratch your back if you scratch mine.”
Parental Investment Theory (Trivers, 1972)
According to Parental Investment Theory, the amount of effort and resources one invests in offspring affects mate choice and behavior.
Females typically invest more in offspring (e.g., pregnancy, lactation), leading them to be more selective when choosing mates.
Males invest less and may compete for access to females, which explains why they are more likely to engage in mating competition and display dominant traits.
Human Mating Strategies
Short-term mating strategies (e.g., casual sex) are more commonly associated with males, as they can increase reproductive success without significant parental investment.
Long-term mating strategies (e.g., committed relationships) are more commonly associated with females, as they require substantial investment in offspring.
Twin/adoption/family studies
These research methods help psychologists separate genetic & environmental influences on behavior and traits.
Types of Studies:
🔹 Twin Studies – Compare identical (monozygotic) vs. fraternal (dizygotic) twins.
High similarity in identical twins = Strong genetic influence.
Example: Identical twins reared apart often show similar IQ & personality, suggesting genetic influence.
🔹 Adoption Studies – Compare adopted children to biological vs. adoptive parents.
Example: If a child is more like their biological parents in intelligence, it suggests genetics play a role.
🔹 Family Studies – Examine traits across biological relatives.
Example: If schizophrenia runs in families, it suggests a genetic component.
Key Findings:
✔ Intelligence: ~50-80% heritability.
✔ Personality: Genetic influence, but environment also matters.
✔ Mental Disorders: Higher risk in biological relatives (e.g., schizophrenia, bipolar disorder).
Heritability of Personality Traits
Heritability refers to the extent to which genetic factors contribute to individual differences in traits.
Studies, particularly twin studies, suggest that many aspects of personality (e.g., extraversion, agreeableness, neuroticism) have a genetic basis.
However, environmental factors also play a role in shaping behavior, indicating a complex interaction between genes and environment.
Genotype-environment correlation
Types of Genotype-Environment Correlations (GxE):
1️⃣ Passive Correlation – Parents provide both genes & environment.
Example: Athletic parents pass on genes for strength & also enroll child in sports.
2️⃣ Evocative Correlation – A person’s genetic traits evoke responses from the environment.
Example: A child with a naturally happy temperament receives more social attention.
3️⃣ Active Correlation (Niche-Picking) – A person chooses environments that match their genetic tendencies.
Example: An extroverted person seeks out social settings like parties and leadership roles.
Key Points:
✔ Explains how genes & environment work together in development.
✔ Changes over time: Passive effects strongest in childhood, Active in adulthood.
✔ Related to Nature vs. Nurture debate—genetics influence how people experience the environment.
Evolutionary psychology
Evolutionary psychology suggests that many human behaviors are the result of adaptations that helped our ancestors survive and reproduce.
Behavioral traits such as cooperation, aggression, parental care, and mate selection are considered adaptive strategies shaped by evolutionary pressures.
Behavioural genetics
The study of how genes and environment influence behavior, personality, and mental health.
Key Methods:
🔹 Twin Studies: Compare identical (100% genetic match) vs. fraternal twins.
🔹 Adoption Studies: Separate nature (biological parents) vs. nurture (adoptive parents).
🔹 Genome-Wide Studies: Identify specific genes linked to behaviors.
Key Findings:
✔ Heritability: Intelligence (~50-80%), personality traits (~40-60%), mental disorders (e.g., schizophrenia ~80%).
✔ Gene-Environment Interaction: Environment influences how genes are expressed (epigenetics).
✔ Polygenic Traits: Most behaviors result from multiple genes working together, not just one.
Examples:
✔ Mental Health: Genetic predisposition to depression, but environment (stress, trauma) can trigger it.
✔ Addiction: Some people have genetic vulnerabilities to substance dependence.
✔ Personality: Twin studies show that traits like extraversion and conscientiousness have genetic influences.
Social neuroscience
The study of how the brain processes social interactions, emotions, and behaviors using neuroscience and psychology.
Key Brain Areas Involved:
🧠 Prefrontal Cortex – Decision-making, empathy, self-control.
🧠 Amygdala – Processes fear, aggression, and emotional responses.
🧠 Mirror Neurons – Help us understand others’ emotions by mimicking their feelings.
Key Concepts:
✔ Theory of Mind (ToM): Understanding others’ mental states.
✔ Empathy & Emotional Contagion: Feeling what others feel.
✔ Oxytocin (“Love Hormone”): Strengthens social bonds & trust.
✔ Social Rejection & Pain: Brain processes rejection similarly to physical pai
Universality of emotions
The idea that basic emotions are recognized and expressed similarly across all human cultures due to evolutionary adaptation.
Proposed by:
🔹 Paul Ekman (1970s) – Identified six universal emotions.
Key Universal Emotions:
😃 Happiness – Smiling, raised cheeks.
😠 Anger – Furrowed brows, tense jaw.
😨 Fear – Wide eyes, raised eyebrows.
😢 Sadness – Downturned lips, teary eyes.
😲 Surprise – Raised eyebrows, open mouth.
🤢 Disgust – Wrinkled nose, closed eyes.
Key Points:
✔ Cross-cultural research shows people from different backgrounds recognize these emotions.
✔ Evolutionary Basis: Emotions helped early humans communicate survival-related feelings (e.g., fear → danger).
✔ Facial Feedback Hypothesis: Expressions can influence emotions (smiling makes you feel happier).
Disgust & Disease avoidance
Disgust evolved as a psychological mechanism to protect humans from disease and harmful substances.
Key Points:
🔹 Evolutionary Function: Avoiding spoiled food, infections, and parasites increased survival.
🔹 Pathogen Disgust: Reacting strongly to things like rotting food, feces, or vomit.
🔹 Moral Disgust: Feeling disgusted by unethical behavior (e.g., cheating, lying).
🔹 Sexual Disgust: Avoiding behaviors that might lead to harmful consequences (e.g., incest avoidance).
i.e., stronger disgust feleings in pregnant people
Nature vs nurture
The debate over whether genes (nature) or environment (nurture) play a bigger role in shaping who we are.
Key Points:
🔹 Nature (Biology): Genetic inheritance influences personality, intelligence, and mental health.
🔹 Nurture (Environment): Upbringing, culture, and experiences shape behavior.
🔹 Interactionist Approach: Both nature & nurture interact (e.g., genes may make you talented in music, but practice is needed to master it).
Examples:
Language Development: We’re born with the ability to learn, but exposure to language is necessary.
Addiction: Genetic predisposition + environmental triggers (stress, peer pressure).
Mental Health: Schizophrenia runs in families, but stressful life events can trigger it.
Can specific gened predict outcome?
Genes influence traits like intelligence, personality, and mental health, but they interact with the environment.
Key Points:
🔹 Genes set potential, but environment shapes expression (Epigenetics).
🔹 Polygenic traits – Most behaviors are influenced by multiple genes, not just one.
🔹 Twin & adoption studies show genetic influences on personality, IQ, and disorders.
🔹 Gene-Environment Interaction: Stress can trigger genetic predispositions (e.g., depression).
Examples:
Height is mostly genetic, but nutrition affects growth.
A person may inherit a risk for anxiety, but a supportive environment reduces its impact.
Identical twins raised separately show similarities but also differences due to experience.
