PSYA01 CH. 3

Understanding the concepts of nature and nurture is critical for psychological studies.
- Nature: Refers to genetic inheritance and biological predispositions.
- Nurture: Involves environmental factors and experiences.
The modern view emphasizes the intertwined relationship between nature and nurture, countering the historical debate of "nature versus nurture."
Francis Galton (1869): Credited for introducing the term "nature versus nurture" and believed intelligence was largely hereditary.
The contemporary perspective considers intelligence to be shaped by both genetic and environmental factors.

The human body has approximately 37 trillion cells, each containing two copies of the genome.
- Genotype: An individual's unique genetic makeup.
- Phenotype: The observable characteristics resulting from the genotype interacting with the environment.

Humans have 23 pairs of chromosomes, with each chromosome containing many genes.
Genes exist in different forms called alleles.
- Each individual inherits two alleles for each gene (one from each parent).
- Example of blood type alleles: A, B, and O, leading to types AA, AO (Type A), BB, BO (Type B), AB (Type AB), and OO (Type O).

Dominant alleles express traits in both homozygous and heterozygous states, while recessive traits only express in a homozygous condition.
- Example: Freckles (dominant) vs. no freckles (recessive).

SERT (Serotonin Transporter Gene): A study shows the interaction between gene types S (short) and L (long) concerning response to bullying.
- Genotypes: SS, SL, LL; neither allele dominates, and their interaction affects emotional disturbance levels.

Approximately 500 individuals in Canada remain missing annually.
In March 2018, Canada initiated the National Missing Persons DNA Program to match DNA records for missing persons with unidentified remains.

Relatedness refers to the probability of sharing alleles across generations.
- Example: 50% chance of sharing alleles with siblings, and 12.5% with first cousins.

Females (XX) have two X chromosomes, while males (XY) have one X and one Y.
- The Y chromosome has significantly fewer genes compared to the X.

Hemophilia is a recessive condition found on the X chromosome.
- Females can be carriers while males who inherit the recessive allele express the condition directly.

Understanding human evolution is crucial for psychology.
- Natural Selection: Darwin's theory indicates survival and reproduction favor traits.
Research shows shared genes across species (e.g., humans share genes with chimpanzees) and specific genetic mutations relevant to unique human attributes.

The study of genes related to psychological traits and disorders, using tools such as genome-wide association studies (GWAS).
- Example: MAOA (Monoamine Oxidase A) gene linked to antisocial behavior, with low activity associated with higher impulsive actions.

Heritability measures the proportion of observed variation in a trait attributable to genetic factors.
- Understanding heritability requires considering environmental influences.

Genetic ancestry testing has raised ethical concerns regarding privacy and the use of genetic information from Indigenous populations.

Evolutionary psychology examines how human behavior develops through survival advantages.
Adaptation can refer to both the physical attributes and behavioral strategies that enhance survival.

Examples of altruism in nature demonstrate the complexity of social behaviors shaped by evolutionary pressures, such as cooperation for mutual survival benefits.

Understanding the intricate relationships between genetics, environment, and evolution is essential for comprehensive insights into human behavior and psychological science.
Future research should focus on integrating genetic findings with social and environmental considerations to address complex human behaviors.