Evolutionary Psychology Flashcards
What is an Adaption?
-Physical or psychological trait that consistently features in a species’ history
- At a previous point in species’ evolutionary history it solved a particular problem that had a fitness-maximizing consequence
- Complex and well-organized
What isnt an Adaption?
Some traits can be down to chance through
- genetic drift – e.g., natural variation & frequency of a trait down to mathematical chance
- by-product of some other trait (sickle cell anemia)
- random
- vestigial trait - e.g., appendix,wisdom teeth, goose bumps
What is a Hominin?
Humans, extinct human species &ancestors
Hominids= great apes
What separates hominins (homo) from other hominids?
Bipedal locomotion:
- Shaped by environment
- Different diet – more varied covering wider area
- Feet developed better arches for bearing weight of torso
- Diet/ different shaped jaws and skulls
Early hominids: Australopithecus afarensis
- Eastern Africa
- 3 million years ago
- Shares some traits with chimps (long arms,curved fingers for living in tress, flat nose, brow ridge)
- Fairly short (around 4 foot)
- Small canines & bipedal
- Lasted 900K years
Early hominins: Homo habilis
-2.2 – 1.15 MYA Sub-Saharan Africa
- Stone tools
- Face less protruding & small canines (change in diet)
- Larger brain than Australopithecus
- Use of tools reflect abstract thought (tools solve problems)
Early hominins: Homo erectus
- 1.9mya – 150kya
- Africa now migrated into Eurasia (possible speciation due to ecological niche – h.heidelbergensis & h. ergaster)
- Long legs and short arms
- 4.9 – 6.1 ft
- Growth rate similar to humans
- Increased brain size – “encephalisation” – can handle and process complex info to own advantage, hunting – exploit the environment in more than one way
- Acheulean technology stone tool technology
Early hominins: Homo heidelbergensis
- 600 – 200 KYA
- Africa, Europe & West Asia
- Ancestor to anatomically modern humans (in Africa)and Neanderthals (in Europe)
- Bigger brain (frontal and parietal lobes – language and touch)
- Taller
- Parabolic jaw shape (change of diet)
Early hominins: Homo neanderthalensis
- 400-40 KYA
- Europe & Eurasia
- Complex stone & bone tools
- Hunting
- Evidence of symbolism (manifest abstract thought)
- Art
- Buried the dead- awareness of own mortality, ritual
-Flutes (from bone) – creating music
Other hominin species
- Denisovans (East Asia)
- Homo floresiensis (Indonesia) – contemporary hominins also died out around same time as Neanderthals
- Many more species emerging – phylogenetic tree of hominins is lot more complex than originally thought
Anatomically modern homo sapiens
- From 200 kya?
- Left Africa into Europe about 75 kya
Differences from Denisovans & Neanderthals:
- No occipital bun
- High forehead
- Smaller teeth and jaw
- Less robust skeleton
- Longer maturation rate
History of symbolism: beginnings
Shell beads from Blombos caves in South Africa, 77-100 thousand years ago(engraved pigment, up to 100 kya
Ostrich shell engravings, 60kya, also South Africa
Using ochre as body paint – alteration of the self to make an impression – signal enhancement
Caves of Altamira (Spain) and Lascaux (France): 25-30 kya
Venus of Willendorf: 22 – 24 kya
Significance of symbolism
- A “diagnostic trait” of humans; “self-domestication” –watershed moment in human history
- Complex sociality, increased cognitive complexity: accumulation of understood associations require episodic memory
- Future planning
- Aspects of cultural traditions embodied in the material replication of forms
- Thinking “at a distance” (between the meaning & object it represents)
- Indicate a “downloading” of object information into the abstract
Language & symbolism
- Impossible without language (external symbolic storage)
- Info conveyed without need for demonstration
- Language is the nexus of symbolic cognition
- Relies on ability to blend concepts to produce new concepts of increasing complexity
- Symbols eventually became systematised, from which grammar emerged
- Underlies humour, spiritual and religious imaginary, appreciation of aesthetics
- Requires neural complexity and dedicated areas of the brain
Development of Theory of Mind
- Ability to understand intentions of others at increasing levels of complexity
- Others’ minds are like our own; similar thoughts and intentions
- Others also see that in us
- Hunting would have required this (Boxgrove site 500 kya; Homo habilis, hand axes)
- Apes have some ToM but appear not to use it collaboratively
- Recursive process (reflect and change) leading to the expectation and reciprocation of help
- Mutual cooperation led to social structures that govern sociality
- Crucial for language (and symbolism)
Social Intelligence Hypothesis (Chance & Mead, 1953; Jolly, 1966; Humphrey, 1976)
Selective pressures caused by social environment- competition & cooperation with conspecifics important factor in evolution and shaping of brain and cognition in animals
Psychological arms race between conspecifics – “Machiavellian” strategies (i.e., ability to manipulate other people) led to large brains and distinct cognitive abilities in primates
Complexity of social interactions in groups = cognitively demanding
Theory of Mind – the ability to put yourself in the mind of someone else
Social Brain Hypothesis (Barton &Dunbar, 1997)
- Correlation between relative brain size (neocortex) and social group size
- Predation is related to group size
- Social cohesion needed to avoid predation
Social Brain Hypothesis
- Sociality is incredibly cognitively demanding
-Extension of pair-bonding relationship maintenance from mate to friend
- Brain developed in response to social demands rather than ecological demands, although ability to exploit a variety of environments also important
Neocortex
- where complex thinking goes on
- not just about regulating basic functions
What does Neocortex size correlate with?
- Grooming cliques
- Rates of tactical deception
- High male ranking reproductive success (negatively) where lower males have to use social deception to attract mates
- The amygdale- part of brain that deals with emotion processing
Neocortex and group size
- Species with large average group sizes are the most corticalised
- As group size increases individuals have to remember more info about dyadic interactions and relations
- Exponential increase in strategic possibilities within polyadic interactions and relationships
Dunbar’s number- Social brain hypothesis
- Calculation that humans have cognitive capacity/ constraint for meaningful info held of 150 individuals
- Not just about memory but integrating and managing info about the constantly changing relationships between individuals within a group
Dunbar’s number
Hierarchical groupings of info held about 150 individuals:
- Clique (3-5 individuals)* Sympathy group (12-20 individuals) (special ties, contacted typically once a month)
- Affinity group/Bands (30-50 individuals) (hunter-gatherer societies – overnight camps)
- Active network/ Clan/ regional group (150 individuals)
- Larger scale groupings – megaband (500 – tribe/1000-2000k linguistic group)
- More than 150 requires formal laws and police force; kinship &affinity become insufficient for social cohesion (Forge, 1972)
Communication in social networks
- Effort required to maintain relationships
Tied to:
- Emotional intensity of relationship
- Likelihood of receiving support from that network member
- Likelihood of relationship decaying in emotional intensity over time
What does relationship quality depend on?
- Time invested in relationship
- Time spent on communication daily is 20%
- Maintaining relationships is highly cognitively demanding (needs more brain)
- Relationships cognitively costly – if you get it wrong it can cost you in terms of survival and reproduction
Birth of evolutionary psychology
- Charles Darwin – “The Descent of Man, and Selection in Relation to Sex” (1871)
- Still relatively young subject field – early 1990s
- Seminal work of Tooby & Cosmides, also Stephen Pinker & David Buss
Tooby & Cosmides (1992) – theoretical background
- Rooted in cognitive psychology information processing approach
Integrated Causal Model:
- Beyond Standard Social Science model which separates culture and other human phenomena from biological, or evolutionary causes
Tooby & Cosmides (1992)- Processing mechanisms
Evolved info processing mechanisms adaptations specialised for behaviours involved in mate selection, language acquisition, family relations & cooperation:
- Generates human culture e.g., religion, art and language
- Basis universal but uniquely shaped depending on specific features of environment like ecology,economy, demographic and inter group social contexts
- Adaptations based on demands of our unique evolutionary history
What is a psychological adaptation?
- ”Reverse engineering” – engineered problem-solving mechanism
- Behaviour is regulatory output from incoming info from environment being processed by the brain
- Shaped by natural and sexual selection
Environmental of Evolutionary Adaptedness (EEA)
- Neural modules/ mechanisms shaped by the Environmental of Evolutionary Adaptedness (EEA)
- Solve problems consistently posed in environment: Domain specific cognitive specialisations:
- Cognitive abilities such as types of sensory perception, preferences for visual and facial stimuli etc., seen in infants from a very young age
- Different adaptive problems over life course –mechanisms emerge according to when needed (e.g.,language acquisition
- Also varies according to sex
How are psychological adaptations designed?
- Emotions and emotional communication
- Humans interact in a mutually beneficial way with non-relatives
- Complex social interaction
- Long-term planning
Different aspects of evolutionary psychology
- Personality
- Altruism & kin selection
- Parental investment theory & parenting
- Mate choice
- Language
Personality as an adaptation- Big 5
- Conscientiousness - reliability
- Extraversion – social adeptness
- Agreeableness - cooperation
- Openness – flexibility
- Low neuroticism- confidence
Personality as an adaptation- “dark traits”
- Psychopathy – evolutionary stable strategy
- Narcissism
- Antisocial behaviour
Altruism
- Poses problem because it increases fitness of another individual at your expense
Kin selection
- Someone from your family benefits
Parenting: Parental Investment Theory
- Level of consideration given to potential mate is a function how much energy is expended in childcare
- Women automatically primary care-giver:9 months given to child-bearing at least
-Men can do absolutely the minimum if they want
Parenting: Parental Investment Theory- Conditions
Short term mating:
- good genes are better (physical characteristics)
Long term mating:
- good “parenting” traits more important
Condition of environment matters:
- High vs Low mortality and morbidity
Parenting in humans
- Humans cant be born anymore developed
- Trade off between big brains and being bipedal (giving birth is still dangerous)
Parenting in humans: Children
Human babies and children incredibly energy/ resource consuming:
- Somatic development
- Learning needed for effective functioning
Parenting in humans: Bi-parental
Bi-parental care beneficial:
- Depends on quality of the mate
- Wider family and community help essential
- Wider family (helpers in nest)
- Allo-parenting (Grandparents)
Trivers- Willard effect (1973)
How a mother apportions energy/ resources to children depending on the quality of the environment
- Males take up more energy/resources and are more sickly
- Mothers in poor condition will have preference for female offspring
- Mothers in good condition are able to invest in male offspring
- E.g., Cigany (Hungarian Gypsy);Mukogodo of Kenya
Mate-choice
Intrasexual (competition between males)
Intersexual (females choose their fellas)
Fisher’s runaway selection (1930)
A physical trait becomes more extreme because it is reliably selected for by females(e.g., Peacock’s feathers)
Hamilton-Zuk’s good genes hypothesis (1982)
Females prefer males who are resistance to parasites – good genes cannot be observed directly, therefore signaled through secondary sexual traits (e.g., plumage – peacocks
Zahavi’s handicap principle (1975)
- Only those with good genes can withstand costly traits (e.g., testosterone)
How EP can explain “abnormal psychology”- Depression
- Adaptive rumination hypothesis (Andrews & Thomson, 2009)
- Signal for help? (e.g., post-natal depression, Watson & Andrews, 2002)
- Might be part of creativity But might be a result of empathy?
How EP can explain “abnormal psychology”- Anxiety/ Neuroticism
- Avoid dangerous predicaments
- Why women are higher in anxiety – related to being primary child-carer
How EP can explain “abnormal psychology”- Schixotypy
Creativity (O-Reilly, Dunbar, & Bentall, 2001)
How EP can explain “abnormal psychology”- Anti-social beh
Adaptive response to hostile environment
How EP can explain “abnormal psychology”- Psychopathy
Cheater strategy – exploit the altruists (Mealey, 1995)
EP & “Abnormal psychology”
These traits work on a spectrum basis – extreme ends are pathological & problematic
- E.g., depression leading to suicide
- Autistic traits leading to severe autism
- Most extreme traits only affect a small majority of the population (5% or less)
- Some operate on a frequency dependent basis:* E.g., psychopathy, can’t have too many cheaters
- Potential mismatch between environments
What is “abnormal” anyway?
- Culturally constructed – culture itself constructed through evolutionary pressures, cultural practices someway solves some evolutionary problem
- Cultures deferentially accept certain behaviours
- Potentially starting point for traits that do eventually become of everyone’s psychology
Controversies in EP
- “Just-so stories”
- After Rudyard Kipling’s book
- Animal physiology explained by random explanation – e.g., camel got his hump because he refused to work, but giving hump where he could store food, meant could work for days
- Evolutionary theory is such that it can be stretched beyond all recognition into explaining psychological phenomena
-Genetic determinism
Controversies in EP- justify racist/ sexist sterotypical views
- Rushton – race & IQ
- Men are from Mars, women are from Venus
-It’s just the way men and women are
- Explanations of rape… Spousal violence… Why step-parents are more likely to killtheir step-children..
Theoretical criticisms of EP
- How do we know how our stone-age ancestors addressed adaptive problems?
- Tooby & Cosmides: there are standard adaptive problems like finding a mate,securing the best possible mate, avoid dying, provide optimal care for offspring
Theoretical criticisms of EP
We cannot know the pre-existing psychology of our ancestors – would have contributed to their interaction with the environment and subsequent psychological development
- Tooby & Cosmides use this as part of their rationale – two-way relationship between environment shaping psychology and psychology shaping environment
Theoretical criticisms of EP
- We don’t know the environment in which our ancestors lived in
- Don’t have other homo species to compare with - - - - Similarities with other species
- Commonalities between cultures –we’re probably a lot more similar than we think
- Pace of technology has outstripped human evolution (Fermi paradox)
Methodological criticisms of EP
- We can’t time trave
-Use of psychometrics
- But are able to generate testable hypotheses
- Other psychology studies completely subject to same methodological problems (general ecological validity and generalisability)
Some genetic basis for homosexuality
- Same-sex alliances
- Seen in other species
- Males who were bred to exhibit same sex-behaviour produced daughters with higher rates of reproduction
- Seems to make sense that there is some level of bi-sexuality – being at one end or the other of this spectrum is just that – there will be variation
