Evolutionary

Edited by me

Tnebergen's 4 Level's Of Behaviour Explanation

Contemporary Object of Study

1. Mechanism (cause): What triggers the behaviour in that moment?

> Immediate biological processes/situational triggers (e.g. hormones, stimuli, social, neural)

2. Adaptive Value (function):

> Immediate function of behaviour in context

> How does behaviour enhance survival or reproduction?

Chronicle (Historical) Object of Study

3. Ontogeny (development): How does behaviour develop over lifespan of individual?

> Maturation & learning

4. Phylogeny (evolution): How did behaviour evolve across species to manifest in this species?

NOTE

> Proximate = How? (Mechanism & Ontogeny)

> Ultimate = Why? (Adaptive value + Phylogeny)

Explain the Biological Basis of Behaviour

> Behaviour can be specifies-specific

> Behaviour has an evolutionary history (e.g. homologous = shared by related species)

> Behaviour is influenced by developmental changes

> Behaviour is affected by biological conditions (e.g. tumours, drugs)

> Behaviour is genetic (heritability/familial risk)

Describe the False Dichotomy Between Genes & Environment

Behaviour is shaped by the interaction of neurobiological mechanisms + environment!

> Political aspect: Lives can be improved by changes in social/developmental conditions

> “Just-so” Theories: Eugenics (e.g. some are poor due to innate inferiority)

Fitness in Evolutionary Theory

Trait/reproductive success relative to competitors within the species/population

• You hold traits that are likely to be inherited by your offspring, carrying the same traits as you into next generation, these traits provide you with a higher level of fitness

Darwin's Theory of Evolution

Species evolve over time through natural selection: individuals with traits that are conducive to fitness & reproduction survive environmental pressures & pass on genes.

Three Components of Natural Selection

1. Variation of traits between individuals (mutation)

2. Selection of traits that confer reproductive success

3. Heritability of traits

Describe Evidence For Evolution of Mental Abilities

Comparative Psychology

> Related species (families) have behavioural similarities (e.g. felines stretching)

Comparative Neuroanatomy

> Brains of humans most like primates (e.g. frontal lobe)

> Primates have highly developed visual cortex vs. dolphins (e.g. hunting vs sonar)

> Brains of humans homologous to other mammals                

> Differences in sizes of regions are a function of sensory/motor needs of species

Describe Evidence of Evolved Mental Abilities Regarding SSDR

Species Specific Defensive Responses

Freezing & survival time when exposed to different predators differ between sub-species of deer mice due to innate differences in threat reactivity produced by evolutionary pressures of ecological niche

> Bred in lab to observe innate differences in SSDR expression between sub-species

> Woodland = More freezing in response to weasels & cats

> Desert = More freezing in response to snake

> Desert = Higher survival time when fed to snake due to defensive behaviours including being out of striking range (avoidance) & leaping away during striking (escape)

Describe Evidence of Artificial Selection of Mental Abilities

Artificial selection is not only applicable to physical characteristics but also mental abilities!

E.G. Tolman's rat maze: Cross-breeding rats who made lots vs. little errors shows cognitive abilities can be artificially selected

Conclusion Natural selection applies to psychology:

1. Variation of traits between individuals (mutation)

2. Selection of traits that confer reproductive success

3. Heritability of traits

Describe the 4 Types of Fitness Exchange

Behaviours confer costs & benefits to the initiator & recipients differently:

1. Mutualism or reciprocity (benefit for recipient + initiator)

2. Selfishness (benefit for initiator, cost for recipient)

3. Altruism (cost for initiator, benefit for recipient)

4. Spite (cost for recipient + initiator)

Altruism

Behaviour which benefits recipients at the expense of the initiator!

Evolutionary Theory: Views altruism as one of two genetic variants of an exchange strategy trait which is contrasted with selfishness

Hypothesis: Altruism should be bred out of gene pool of a population because selfish people receive help without paying a cost.

Inclusive Fitness

Total fitness = direct fitness (own offspring) + indirect fitness (offspring of others with same trait

The total effect an individual has on proliferating its genes by (1) producing its own offspring and (2) providing aid that enables relatives/offspring to survive & reproduce.

How Can Inclusive Fitness Explain Evolutionary Conservation of Altruism

Altruistic traits can survive because altruistic individuals support the survival of offspring and other relatives who hold the same trait & therefore increase their chance of survival & reproduction

How Does Kin Selection Protect Altruistic Traits?

The cost (c) to the individual initiator is outweighed by their altruistic behaviour benefiting (b) the survival and reproductive success of genetic relatives (r), ultimately increasing the conservation of genes related to altruism at the population-level (r x b > c).

E.G. Self-Sacrifice Instinct in Bees

> Bees die upon stinging predators

> BUT bees have high relatedness (all workers are 100% related to fathers & 50% related to Queen, making siblings 25-75% related)

> Sacrifice causes individual death but in protecting the highly genetically-related hive, ensure the propagation of altruism

How Does Reciprocity Protect the Survival of Altruism?

Acts which appear altruistic in the short-term but involve future benefit if it is later reciprocated. Conditions of reciprocal altruism:

1. Propinquity (increased chance of future encounter)

> Don’t need to both benefit immediately if you encounter recipient later (e.g. trade & also to detect cheating)

2. Slow Discounting of Delayed Rewards

> Allows inter-temporal choice to favour altruism

> Delayed rewards are not discounted when cost of altruism is low & future benefit appears closer

3. Exchange of low cost for high benefit

> Trade benefits everyone if benefit to you – cost to you > 0 & benefit to them – cost to them > 0

4. Self-regulating

> Detecting/punishing cheating + instinct for fairness)

E.G. Trade Surplus of Blood Observed in Vampire Bats

> Recently fed vampire bats give blood to starving bats because they have a surplus of survival time

> 10mg is only 8 hours of survival time if recently fed but 20 hours if near starving (low cost to donor, high benefit to recipient)

> Reciprocation = net gain in survival time for colony if every bat supports each other

Evolution of Social Contract

In cooperative social groups, individuals who receive benefits must pay an proportional cost to maintain common good

> Common good = benefits to everyone who live in a cooperative social group

> Selfish individuals have a fitness advantage

Maintaining cooperative group requires

a) Mechanism to ensure that benefits go to those who contribute to common good

b) Need to detect selfish individuals who cheat

E.G. Evolution of Fairness in Primates

> Monkeys share food rewards when noticing differential treatment by experimenters

Explain the "Punishing Cheaters" Study

Motivation to maintain common good depends on punishment in humans!

> Each round, Ps are given some money & choose to donate some to a common good & keep the rest

> Everything that’s donated is doubled and then equally shared among players

> People start to contribute to common good money pot when punished

Describe the social theory of intelligence in evolution

Cohesive social groups provide overall advantages to fitness to the members of the group

Humans display prosocial behaviour towards strangers and without expectation of direct reciprocation. How is this maintained? By benefits of reputations and benefits from a culture of trust. There is an importantance of protecting prosocial culture and social norms

Proposes that benefits of cooperation are so strong that humans have evolved enhanced ability & motivation to detect & punish cheaters!

Equally, because the benefits of cheating are also strong, so people have evolved ability to cheat!

What Does Performance on the Wason Selection Task Show?

Humans have innate motivation to detect cheating!

> WST = Cognitive test of logic

> "Is the card following the rule?" Pick which card to check to see if rule was broken

> Ps more likely to solve WST when rules are presented to detect cheating (e.g. "if a person is drinking beer, they must be over 18" > "if p on one side, q on the other"

What Does The Locust-Grasshoper Case Study Show?

Role of epigenetics!

Locusts & grasshoppers are genetically identical only difference is phenotype (green vs. black).

Locusts turn black & start swarming/become aggressive in response to high population density & food deprivation

What Does the "Dull-Bright Rats" Study Show?

Genes are affected by environment!

> Restricted early environment eliminates difference in dull vs. bright rats (both become dumb)

> Enriched early environment helps dull catch up to bright

Fixed Action Pattern

Sequence of behaviour which is innate & carried out in full once elicited by sign stimulus (e.g. egg-rolling in Geese).

Sign Stimulus Triggers fixed action pattern (e.g. egg to geese, courtship behaviour in fish, red under-belly = aggressive behaviour in fish)

Supernormal Stimuli Exaggerated sign stimuli elicits proportionally exaggerated instinctive response.

Tinbergen's Explanation of Instinctive Behaviour

Hierarchical model of explaining instinctive behaviour in which motivation/drive is the top level

1. Motivation-Drive (defence, reproduction)

> Different drives compete & inhibit each other

2. Specific action patterns

> Selected once motivation reaches threshold

> E.G. fighting/mating

3. Fixed Action Patterns

NOTE CRITICISM!

> Many instinctive behaviours involve mastery of previous behaviours & thus not purely instinctive (e.g. maternal behaviour in rats)

> Species-typical instincts can be modified by experience

(e.g. language in humans, song in birds)

> Limited application to humans (no evidence of FAP)

What is Important About Lorenz' Imprinting Studies?

Shows that learning is not always gradual or flexible but time-limited by critical periods!

Critical Period Concept Specific, limited window in early development where things must be learned (e.g. imprinting in ducks).

> Time-limited: If opportunity missed, behaviour may develop abnormally

> Species-specific: Often linked to survival (e.g. recognising parents)

Explain Why Equipotentiality is False in Learning/Conditioning?

Conditioning assumes equipotentiality (all stimuli have equal chance of association with any outcome) BUT the brain is not a “general-purpose learning device”

1. Taste Aversion

> Develops despite low contiguity (high inter-stimulus interval) between food & later illness!

2. Biological Preparedness

> Seligman's theory that organisms have a biological readiness to form certain associations based on evolutionary relevance.

> Phobia of ancestral threats are learned faster & resist extinction

E.G. Monkey & snakes vs. flower

E.G. Human & snakes/spiders/heights(ancestral threat) vs. cars(modern threat)

E.G. Rats preferentially associate poisoning with flavour vs. audio-visual stimuli (Garcia & Koelling, 1966).

How Does Motivational Drives Affect Instrumental Learning?

When stimuli are related to instinctive drives, instinctive behaviours dominate over learned behaviours!

1. Breland (1961) “Misbehaviour of Organisms”

> Pigs can be easily shaped to pick up coins BUT harder to teach to drop coin because picking up coins are food-like objects & triggers hunger motivation

2. SSDR & Avoidance Learning

> Threat activates defensive motivation, so avoidance learning is easiest when required behaviour matches natural defensive response (e.g. easy to teach rats to run away from shock but hard to press lever to avoid shock).

Pinker's Modern Definition of Instincts

Instincts are based on the urge/pressure to learn & innate competence!

> Evolution provides drive, urge & preparedness to learn

> Culture teaches when to express that behaviour