Lecture Notes

Overview

• Discussed feedback from office hours, particularly around behavior genetics.
• Focus on understanding heritability and inherited traits.
• Clarified common misconceptions regarding genetics in relation to traits.

Key Concepts

Heritability vs. Inherited Traits

• Inherited Trait: A trait that is passed down genetically (e.g., humans having five fingers).
• Heritability: The extent to which genetic factors contribute to variability in a trait within a population (e.g., heritability for number of fingers is ~0% due to environmental factors).
• Important to distinguish between these concepts to avoid misconceptions perpetuated by media reporting.

Gene-Environment Interactions

• Always present; it’s misleading to separate them.
• Understanding this helps clarify behavioral genetics and its implications.

Approaches to Biology of Social Behavior

• Three approaches:
  1. Evolutionary Biology
  2. Molecular Biology
  3. Behavior Genetics
• Each approach has its own merits; none are inherently wrong but vary in explanatory power.

Epigenetics

• Defined in three levels:
  1. Culture/environment affecting biology.
  2. Environment affecting gene expression (on/off).
  3. Molecular mechanisms (chromatin remodeling, methylation).
• The relationship between culture and biology is complex and multi-faceted.

Behavior Genetics

• Divided into classical and modern behavior genetics.
• Classical: Twin and adoption studies aimed at inferring genetic influences.
• Modern: Integrates molecular biology with genetics to analyze behavioral variability in humans.
• Importance of ruling out environmental factors to assess genetic contributions.

Critiques of Behavior Genetics

• Often misinterpret data (e.g., simplistic genetic percentages).
• Useful for demonstrating less significance of environmental influences in specific domains.

Upcoming Schedule

• Next Lecture: Focus on ethology, a different approach to understanding animal behaviors.
• Catch-Up Lectures: Overview of nervous system and endocrinology, designed for those with little prior background.

New Research Discussion

• Reference to the New York Times article about a study comparing skills in the game "Shoots and Ladders" between populations in Nepal and Belgium.
• Encouraged critical questioning of the study's methodology and implications.

Example Questions for Analyzing Studies

• Sample size, methodology, and controls?
• How significant are the results?

Recognizing Relatives in Animals

• Importance of recognizing kin for evolutionary behaviors.
• Examples of mechanisms for kin recognition:
  • Olfactory cues: Use of pheromones and unique protein signatures (MHC).
  • Innate vs. Imprinted Recognition:
    • Innate: Mechanisms present at birth (e.g., olfactory recognition).
    • Imprinted: Learning through experience (e.g., recognizing smell of offspring).

Human Kin Recognition

• Humans use a cognitive approach to recognize relatives.
• Infants can recognize their mother’s smell and voice shortly after birth.
• Studies show that children raised together often don’t marry due to perceived sibling-like bonds.

Cultural Influence on Kinship

• Research in different cultures indicates strategies of avoiding inbreeding by recognizing kin through social exposure and bonding.
• Cognitive strategies for determining kinship include recognizing consistent caregivers, physical resemblance, and shared experiences.

Conclusion

• Transition to ethology for understanding behavior hardwiring and environmental influence in future classes.
• Emphasis on the manipulability of kin recognition in social contexts, with implications for understanding human behavior, aggression, and cooperation.