Summary of "AP Psychology: 2.1-2.2 Heredity, Environment, and the Endocrine System"

This video lesson by Dr. Swope provides an overview of key concepts in AP Psychology related to heredity, environment, and the endocrine system. The content is structured around four main topics and integrates review, explanations, and application exercises.

Main Ideas and Concepts

1. Heredity and Genetics in Behavior

Genetic Instructions and Brain Development:
- About 30% of human genes (~8,000 of ~24,000) are dedicated to brain development.
- Most genes are shared among humans, with only a small percentage accounting for individual differences.
- Genes act like blueprints for building the human body, but these blueprints are not always followed exactly due to environmental influences.
Genes Are Not Destiny:
- Genetics influence behavior but do not rigidly determine it.
- The relationship between genes and behavior is bi-directional: genes affect behavior and environment can affect gene expression.
Epigenetics:
- The study of how environmental factors (e.g., stress, nutrition, toxins) can turn genes on or off without changing the DNA sequence.
- Epigenetic changes can occur prenatally and continue throughout life.
- Example: The 5-htt gene affects serotonin reuptake, which is linked to mood and depression.
- Evidence suggests environmental factors in collectivist societies may reduce depression rates via epigenetic mechanisms.
- Animal studies (e.g., stressed rats) show that fear responses can be inherited epigenetically.
Polygenic Traits:
- Most behaviors and traits (e.g., intelligence, mental illness) are influenced by multiple genes, not a single gene.
- Caution against oversimplified media claims about "the gene for" complex traits.
Research Methods in Genetics and Environment:
- Experiments controlling genetics (e.g., monozygotic twins raised in different environments) are ideal but often unethical.
- Case studies of naturally occurring twins raised apart provide insight into genetic vs. environmental effects.

2. Key Scientists and Theories

Charles Darwin:
- His theory of evolution by natural selection underpins much of psychology’s understanding of behavior.
- Traits and behaviors are adaptive and serve evolutionary purposes.
William James:
- Known as the father of American psychology.
- Developed functionalism, emphasizing that behaviors and traits serve specific functions related to survival.
- Explored consciousness and its purpose, linking evolutionary theory to psychology.
Evolution and Behavior:
- In animals, instincts (e.g., spider web building, bird migration) are clear examples of inherited behavior.
- In humans, it is difficult to isolate inherited behaviors due to environmental and societal influences.
- Some basic behaviors like feeding and facial expressions may have instinctual components.

3. The Endocrine System and Behavior

Overview:
- The endocrine system uses hormones as chemical messengers traveling through the bloodstream to regulate bodily functions and behavior.
- Compared to neural communication (fast, like the Internet), hormonal communication is slower (like snail mail).
Interaction Between Nervous and Endocrine Systems:
- Some chemicals (e.g., epinephrine/adrenaline) function as both hormones and neurotransmitters.
- Hormones can influence neurons and vice versa, showing a complex interaction.
Key Components:
- Hypothalamus: A brain region that regulates the Pituitary Gland and controls basic drives like hunger, fear, anger, and sexual behavior.
- Pituitary Gland: Often called the "master gland," it regulates other glands.
- Adrenal Glands: Produce adrenaline, which is critical in fear and stress responses.
- Testes: Produce testosterone, linked to aggression (though causation is not definitive).
- Pancreas: Monitors blood sugar and influences hunger.
- Ghrelin: A hormone that signals hunger by causing stomach growling.
Behavioral Examples:
- Fear and anger involve hormonal feedback loops between the Hypothalamus, Pituitary Gland, and Adrenal Glands.
- Hunger is influenced by both brain signals and hormones like ghrelin.
- The relationship between hormones and behavior is interactive and complex, not simply cause and effect.

4. Application and Exam Practice

The video concludes with an applied scenario involving a fictional teenager, Freddie Schmidlap, who struggles with motivation, nervousness, anger, and hunger.

Students are prompted to write paragraphs explaining how epigenetics, the Hypothalamus, and the pancreas relate to Freddie’s situation, emphasizing: