Tool Manufacturing and Evolution

Tool Manufacturing

• Previously, humans were considered the only tool-makers; primates also utilize tools like hammers and fishing spears.
• New Caledonian crows create two types of tools: one involves sticks with hooks for insect extraction, the other uses pandanus leaves.

Convergent Evolution

• Represents independent evolution of similar traits in different species due to natural selection favoring similar adaptations.

Natural Selection Requirements

• Variation in traits exists among individuals.
• Traits must be heritable for future generations.
• Some variants are better suited for survival than others.
• Competition for limited resources leads to the survival of advantageous traits.

Process of Natural Selection

• Mutation introduces genetic variation.
• Unfavorable mutations are eliminated.
• Reproduction and mutation continue to create variation.
• Favorable mutations have higher survival rates, leading to their propagation in subsequent generations.

Nim Chimpsky

• Demonstrates attempts at language acquisition in apes.
• Apes can learn isolated symbols but lack mastery of complex language structure (syntax and semantics).

Types of Intelligence

• Domain-specific intelligence: Tailored to specific tasks.
• Domain general intelligence: Applicable across various contexts.

Basic Terminology

• Genotype: Set of inherited DNA responsible for traits.
• Phenotype: Observable characteristics resulting from the genotype.
• DNA: Contains genetic information in cells' nuclei, structured in 23 pairs of chromosomes.
• Chromosome: Thread-like structures in the nucleus; each is a DNA molecule.
• Gene: Segment of DNA coding for specific proteins.
• Allele: Variations of a gene at the same position.
• Locus: Location of a gene on a chromosome.
• Homozygous: Two identical alleles for a trait.
• Heterozygous: Two different alleles for a trait.
• Dominant: Allele that expresses its effect in both homozygous and heterozygous states.
• Recessive: Allele that is expressed only in homozygous conditions.
• Polygenic inheritance: Traits influenced by multiple genes, common in psychological traits.

Genetic Inheritance and PKU

• PKU is a metabolic disorder linked to a recessive gene on chromosome 12, leading to intellectual disabilities.
• Manifestation of PKU requires two copies of the gene from both parents; produces high levels of phenylketones in urine.

Genes and Aggression

• The "warrior gene" on the X chromosome affects Monoamine oxidase A production, linked to neurotransmitter metabolism.
• Inadequate metabolism of neurotransmitters like serotonin and dopamine correlates with heightened aggression, particularly among maltreated children.

Dictator Game

• A social-economic experiment where one player decides how much to share from a sum of money with another player.
• Cultural differences in generosity reveal variations, e.g., Americans donate 47% on average, while African hunter-gatherers like the Hadza donate approximately 25%.

Muller-Lyer Illusion

• An optical illusion where two lines appear different in length despite being equal; highlights how perception of length varies culturally.

Psychology’s Population Bias

• A 2008 survey revealed that 96% of subjects in top psychology journals were from Western industrialized countries, indicating a potential research bias.