Voles in Love: Proximate & Ultimate Descriptions

The New Psychology

• “In the distinct future…psychology will be based on a new foundation, that of the necessary acquirement of each mental power & capacity by gradation.”

• It’s easy to think as things from biological standpoint

• That mental things we subjected to evolution too

• Variation (random), selection (best fit), heredity (passed to offspring; was weak in Darwin's (OTOOS) book)

The Modern Synthesis

• The Modern Synthesis: historical unification of Darwin’s theory of natural selection w/ genetic theories

  • Disregards Lamarck’s inheritance of acquired characteristics

  • disregards blending theories of inheritance

1. We Know Enough - all known evolutionary phenomena explainable w/ current genetic mech.

2. Population thinking - population genetic diveristy is key; ecological factor include niche occupation, (isolation) barriers to gene flow

3. Evolution is (mostly) graudal - small genetic changes can lead to new species, though geological separation & extinction

   1. new species: different species can’t reproduce w/ each other; aka can’t rpduce fertile offspring

4. Selection Rules - by far the main mechanism of change; slight advantages in phenotype to surrounding environment

5. The Bones say Yes (Palentology) - know fossils provide historical observations consistent w/ evolution

Ethology: Konrad Lorenz

• Ethology: branch of biology emphasizing the study of proximate mechanisms & adaptive value of animal behavior

  • reaction to behaviorism that dominated American psychology (e.g., Skinner)

• One of the founders of ethology Lorenz is known for famous studies of imprinting in geese

  • goslings imprint on the first big moving object they see after hatching

Konrad Lorez, Nike Timbergen & Ethology:

• “…our cognitive & perceptual categores, given to us prior to individual experience, are adapted to the environment for the same reasons that a horse’s hood is suited for the plains before the horse is born, & the fin of a fish is adapted for water before the fish hatches from its egg.”

• lots of inborn cognitive/perceptual that are form before visual

• Timbergen’s Level of Analysis (→ to fully understand behavior, look at each level):

1. Proximate (genes, brains, stimuli) → what triggers it? (from environment)

2. Ontogentic (life history) → @ what age/time does it start (in development)

3. Phylogenetic (species history) → timing ancestory/trying to reconstruct history

4. Ultimate (adaptive value) → how did it give advantage?

Niko Tinbergen: Four Levels of Description for Behavioral Traits

• individual organism

  • proximate → mechanism

    • how does it work? (genes, chemistry, brain areas, stimuli that trigger the trait)

  • ontogentic → development

    • when does it develop? (during lifespan; birth? childhood? sexual maturity?)

• species/population

  • phylogenetic → historical

    • where did it come from? (sequence of events leading to the trait)

  • ultimate → adaptive value

    • why did it evolve? what does it do? (trait’s function in providing survival or reproductive advantage)

Voles in Love? A tale of 2 species:

• prairie voles

  • monogamous

• meadow/montane voles

  • polygynous

Proximate level: voles

• oxytocin & vasopressin hormones may create bonding by activating brain areas for pleasurable feelings, e.g., ventral pallidum

• more amount/spread out in prairie voles compared to meadow voles

• If artificially inserted vasopressin can artificially create bond w/ female never mated with

• if vasopressin antagonist, can prevent bonding after mating

Phylogenetic Level: Vole Mating Systems:

• in history, where did behavior come from?

• how did environment affect mating behavior?

Adaptions & Natural Selection:

• “The significance of an adaptation can only be understood in relation to the total biology of the species”

• Adaptations: heritable species → typical traits that have evolved to directly enhance survival & reproduction; Williams said that true adaptations should be:

  • reliable: regularly develops in all species members & performs dependably

  • efficient: solves some adaptation problem well

  • economical: works w/o huge costs to the organism

• By-products: traits that have no direct adaptive value themselves, but appear to be carried along by an adaptive trait

• Noise: random effects from chance variations in genes, environment, or development; not an adaptation nor thought to be tied to one as a by-product

• EX: Why do men have nipples:

  • adaptations:

    • nipples on mammals, esp. females (mammary glands)

    • the umbilical cord

  • by-product:

    • nipples on males

    • the belly button

  • noise:

    • shape of individuals' nipples

    • shape of the belly button

EvoPsych: The Santa Barbara School & the “5 Principles”

• Principle 1 - the brain is a physical system. It’s computer-like circuits are designed to generate behavior appropriate for your environment

• Principle 2 - our nerual circuits were designed by natural selection to solve problems our ancestors faced during our species evolution

• Principle 3 - consciousness is just the tip of the iceberg; most of what goes on in your mind is hidden from you. Your conscious experience can mislead you… Most problems that you experience require very complicated neural circuitry (to solve)

• Principle 4 - different neural circuits are specialized for solving different adaptive problems. These circuits are often terms Evolved Psychological Mechanisms (EPMs)

• Principle 5 - Our modern skulls house a stone age mind. Much of the human mind (behavior formed as adaptations to conditions in the late Pleistocene era (about 150,000 years ago)

• cosmides & tooby

Evolbed Psychological Mechanisms (EPMs)

• EPM’s: Specific functional structures of the human mind (“algorithms”) shaped by natural & sexual selection to solve survival & reproductive problems

  • Core properties of EPMs:

    • input-sensitive: triggered/activated by specific environmental or intentional cues (e.g., sight of a predator or potential mate)

    • decision rules: process information w/ internal “If-then” logic

    • adaptive output: generate physiological, cognitive, or behavioral responses aimed at solving an ancestral problem

    • domain-specific: unlike general learning, EPM’s are shaped to tackle distinct challenges (e.g., avoid insects, choose unhealthy partners, detect cheaters)

• Environment of Evolutionary Adaptedness (EAA): all the selection pressures caused by adaptive problems that led to adaptations (including EPMs)

  • positive selection → leads to a trait spreading in a population

  • negative selection → reduces (or eliminate) traits presence/influence

• balancing selection: doesn’t provide advantage but doesn’t harm → stays in gene pool

• Evolutionary Time Lag’s (“Mismatch”): beneficial adaptations from a species past may be costly or even maladaptive in their current environment (natural selection generally can’t operate as fast as environmental change)

  • recall Principle #5 about living in a modern age w/ a stone-age mind