Lectures 5 & 6: Human Evolution

Nativism

Knowledge of the world is mostly innate, and determines certain abilities

• this view is associated with the idea that nature (genes) determines behavior

Empircism

At birth, mind is a tabula rasa (empty state), nothing in terms of behavior and knowledge is inherited; al is learned

• this view is associated with the idea that nurture (environment) determines behavior

Interactionism

Certain basic abilities and knowledge are innate, but can be influenced by experienced, which in turn can change what innate behaviors are expressed, which influences what will be experienced, and so on. This view is supported strongly by the available evidence

Genotype

The compete set of an organisms’ genes

Phenotype

The overt characteristics of an organism (the properties we can observe resulting from what genes are expressed)

• phenotype is product of genotype and environmental factors, and experience

  • Example: skin color in humans. Our genes determine how much melanin we produce, but exposure to UV-B radiation can increase melanin production, which darkens the skin because melanin is black

Monozygotic twins growing up together

Provide data for equal “nature”, similar to”nurture”

Monozygotic twins growing up apart

Provide data for equal “nature”, different “nurture”

Dizygotic twins growing up together

Provides data for similar “nature”, similar “nurture”

Dizygotic twins living apart

Provides data for similar “nature”, different “nurture”

Siblings growing up together

Provides data for similar “nature”, similar “nurture”

Individuals not related to each other living apart

Baseline control group. Provides data for genetically unrelated, separately living individuals that should correlate in IQ scores randomly

Dizygotic (fraternal) twins

Two sperms fertilize two eggs

Monozygotic 9identical) twins

One sperm fertilizes one egg and the zygote splits in two

The multiregional hypothesis

Proposes regional continuity with gene flow maintaining one species

Out of ΑFrida hypothesis

Argues modern humans originated recently in Africa, replacing archaic populations elsewhere

Domain

Broadest division of life; based on cell type and molecular structure

• ex: eukaryotic (cells with nuclei)

Kingdom

Groups organisms with basic body organization and nutrition

• ex: animalia (multicellular, heterotrophic)

Phylum

Groups organisms with major structural features or body plans

• ex: chordata (notochord, meaning “back cord”, or dorsal nerve cord)

Class

Subdivision of phylum; shares more detailed traits

• mammalia (hair, mammary glands)

Order

Animals sharing major adaptive traits: mammals with grasping hands/feet, forward-facing eyes, large brains relative to body size) is primate

Family

(Animals generally originating from common ancestor with more detailed morphological similarities) is hominid are (“great apes”, consisting of chimpanzee, gorillas, orang-tuna’s, bonobo)

Genus

(Subdivision of a family — closely related species that evolved from recent common ancestor) is Homo

Species

Animals that can interbreed and produce fertile offspring is sapiens

Cognitive revolution

Started about 70k years ago

• Mind’s Big Bang (50,000 years ago). Rapid shift to symbolic behavior, art, ornaments, complex tools, long-distance exchange, possibly trade

  • Cave art and music, indicating the capacity for symbolic cognitive processing, imagery

  • They used beads and other body ornaments, which suggests awareness of social identity, and the need for cultural expression

  • They improved weapons and tools, which made hunting safer and more efficient, and it knowledge was preserved and transmitted between generations

  • Likely these humans had their of mind and were highly cooperative, implying significant complexity

  • Language enabled new forms of memory, teaching, gossip, and coordination

• Possible consequences of increase in brain development affecting our mind/behavior are:

  • We spend more time looking for food to provide energy for brain

  • Muscle atrophy to help feed energy needs of brain

  • Human premature bright due to bigger brain of newborn and smaller pelvis of mother (upright walk)

    • Babies are very plastic and not “set” in their way: highly adaptive

    • Human children are helpless for a long time

    • Requires raising child by help of group; evidence for “kindergartens” as early as homo neanderthalensis

  • Cooking (handling fire, started around 300K years ago), which increases nutritional density of food and dramatically improves digestion speed

  • Humans have a language that is unparalleled compared to the languages of other animals

    • Ability to communicate knowledge about world planning complex actions (avoiding predators)

    • Ability to communicate about social structure: larger groups of humans can live together (up to 150, after that information cannot be shared effectively about everyone)

    • Ability to communicate about things that do not exists (such as myths, laws, rules, concepts)

      • Friendliness, cooperation of strangers (myths, concepts)

      • Rapid innovation of social behavior (laws, traditions)

      • Increasing size of functional human society’s from kinship tribes to villages, cities, nations

Agricultural (or Neolithic) revolution

STarted about 12k years ago

• for 100k years hominids depended on hunting and gathering for survival

• Humans followed their food around, camped around protective sites and waterholes

• Bit about 12k years ago agriculture emerged, annals were domesticated

Consequences of agricultural lifestyle

• concept of ownership

• Instead of kinship tribal bands, villages and cities and nations became default social structures

• Diet change from wholesome and varied to monocultural. Nutrition-related diseases occurred, such as tooth caries

• Settled humans have reduced knowledge about the wider surroundings, such as animals, plants, geography compare to nomadic humans

• Sedentary lifestyle due to spending significant more time on working for food compared to hunter and gatherers. Work-related diseases emerged

• Evolutionary psychologists argue that our minds remained hunter-gatherer minds and our behavior reflects this. We are not yet adapted to the settled lifestyle

Scientific revolution

Started about 500 years ago. Galileo, Bacon, Descartes and others developed scientific method to understand nature with the aim to control it (an old human dream , perhaps born it of our past animal in the middle of the food chain)

Industrial Revolution

Started about 200 years ago

Anthropocene

Maybe since 12k years, maybe since the 1960s. Proposed new epoch. Outcomes of agricultural and scientific revolution led to a new era in Earth history, characterized by human ability to modify entire biosphere, changing climate, geology, ecosystems