1
Q
what does evolution do to psychology?
A
bridges it as a biological science
2
Q
adaptation
A
- biological traits help an individual to survive and reproduce in its habitat
- serve some function to interact w/ environment
- i.e. raccoons have sensitive front paws to discriminate btwn food/non-food in the dark
- i.e. bats echolocation
3
Q
what do cognitive psychologists study?
A
higher mental processes like:
- selective attention
- memory encoding
- memory retrieval
4
Q
what do adaptations emerge in development as a result of?
A
activation of relevant genes in interaction w/ relevant aspects of environment
5
Q
natural selection (charles darwin/alfred russel wallace)
A
the differential survival/reproduction of organisms as a result of heritable differences btwn them
6
Q
4 basic mechanisms of evolution
A
- natural selection
- mutation
- genetic drift
- migration
7
Q
three essential components of natural selection
A
- individual differences: significant individual diffs within pop’n
- differential reproduction: those differences impact individual chances of surviving/reproducing
- heritable differences: traits tht give rise to differential reproduction have a genetic basis
8
Q
natural selection: there r many fish in a sea. blue fish camouflage and red fish stand out. what happens?
A
- red fish get eaten more often
- blue fish survive n reproduce more often than red fish
- blue fish tend to have blue fish babies (heritable trait)
- over successive generations pop’n fully blue bc favourable traits r passed on
9
Q
what kind of selection have researchers observed in wild populations?
A
stabilizing selection
10
Q
stabilizing selection
A
- selection against any sort of departure from the species-typical adaptive design
- keeps traits stable over generations
11
Q
darwin’s finches:
finches on an island. drought occurred in 1977. food was scarce, small seeds got eaten, large/tough seeds left (which they didn’t usually eat). wht happened?
A
- display natural selection over one generation
- birds with big/heavy beaks could eat the hard seeds and survived the drought
- birds with small beaks died and large beaked birds reproduced: offspring inherited big beals
- btwn 1976 and 1978, beak length increased from 9.4mm to 10.2mm
12
Q
what happened to the finshes’ beak size after the drought ended and small seeds were produced again?
A
average beak depth returned to pre-drought sizes
13
Q
is natural selection about “survival of the fittest?”
A
- no
- fitness is referring to reproductive success NOT physical fitness
14
Q
darwinian fitness
A
average reproductive success of a genotype relative to alternative genotypes
15
Q
evolution
A
change in gene frequencies over generations, in part due to the introduction of new gene variants via mutations
16
Q
in the fish example: wht if a new predator emerged which could see bluefish easier than redfish?
A
- red fish has higher fitness
- so, gene pool shifts towards red phenotype
17
Q
how do new gene variants arise?
A
mutations
18
Q
what happens when natural selection acts on mate-finding/reproductive behaviours?
A
sexual selection
19
Q
sexual selection (darwin)
A
the component of natural selection that acts on traits that influence an organism’s ability to obtain a mate, resulting in differential reproductive success
20
Q
darwinian fitness in peacocks
A
- peacocks have large tails (shed after mating season)
- cons: energetically expensive, hard to hide from predators, hard to move, increases risk of dying
- BUT: increase chance of mating so it stays
21
Q
darwinian fitness in elk
A
- stags fight, winner monopolizes harem of female elk
- only males have heavy antlers, so they lack stamina and can get stuck more often
- negative impact on survival
- increased chances of sexual mating
22
Q
types of sexual selection
A
- inter-sexual: female choice/interaction btwn sexes (peacocks)
- intra-sexual male competition/interaction in same sex (elk)
23
Q
how do we know if a trait is sexually selected? what kinds of sexually selected traits exist?
A
- display features and weapons
- if anatomical trait different btwn sexes
- if sex difference only exists/is exaggerated in breeding season
24
Q
what kind of tails do peahens prefer?
A
- experimentally shown that they prefer tails with more eye spots (even just 1-2% more)
- prefer good left/right symmetry
25
mate choice preferences (why do these preferences exist?)
- female choice picks out males with best resistance to disease
- want best genes for being healthy for kids
26
types of species-typical behaviours
- movement (topography): how they hop/fly
- habitat preference
- group size
- mating preferences: monogamous/polygamous/active parents
27
how can we confirm that behaviour evolves?
- selection experiments (also called behavioural genetic studies)
- keep animals in captivity and selectively breed those that have a specific behaviour (i.e. aggressive)
- can change animal's typical behaviour in a few generations
28
what is the most popular animal to use in behavioural genetics?
- fruit fly: drosophila
29
how are cognitive processes/behaviours similar to physical traits?
they are also subject to selective pressures to meet particular goals
30
altruism in animals
honey bees:
- most don't have reproductive organs/never reproduce
- instead spend life servings queen's eggs
ground squirrels:
- whistle blowing squirrel alerts others of predator while putting itself in danger
humans:
- spend time helping one another
31
what level does evolution act at?
- level of genes
- natural selection favours the "selfish gene"
32
4 types of social behaviours
- cooperation
- altruism
- selfish
- spite
33
cooperation
positive effect on actor and recipient
34
spite
negative effect on actor and recipient
35
selfish
- positive effect on actor
- negative effect on recipient
36
altruism
- negative effect on actor
- positive effect on recipient
- behaviour in which the actor incurs a cost to provide a benefit to a recipient
37
why aren't we always selfish?
- sometimes, cooperation reaps more benefit than selfishness
- i.e. one bad team player: cost of teaching them is worth the payoff of winning more
38
is adaptations for the good of the group/species?
- no
- for the good of the gene
- favouring the good of the group is more of a side effect
39
foraging in groups for food
- increases personal success for obtaining food
- even though others may sometimes take some from bird, there is higher net opportunity to take food from others
ALSO:
- heads are down and attn is divided when eating
- in groups, others can look for predators
40
what do the graphs for foraging/scanning look like?
- individually: as flock size increases, head jerks up decrease
- flock: as flock size increases, head jerks up increase
- each individual gets more time to eat but the flock is more vigilant altogether
41
can selection be for the good of the group even if the helpful genes involved suffer?
no
42
does foraging/vigilance in groups count as altruism?
- no
- actor gains from performing the behaviour
43
what do altruists do while helping others?
decrease their own fitness
44
lemmings
- small rodents
- die by suicide when pop'n becomes too large (altruistic act) so others have enough food
- two genes exist: altruistic suicide and selfish restraint
- altruistic gene dies, selfish one continues
- unless... genes involved in altruistic behaviour produce more copies of themselves
45
eusocial hymenoptera
- in this lvl of social organization, most individuals spend lives serving colony w/o reproducing
- all ants, some bees/wasps
46
W.D. Hamilton's insight on altruism
genes for altruism could be successful if they helped identical copies of themselves
47
types of fitness (W.D. Hamilton) + inclusive fitness theory
- direct fitness: fitness from personal reproduction
- indirect fitness: fitness from the reproduction of close genetic relatives
- theory: we can increase our own fitness by helping kin raise their offspring even if it reduces our direct fitness
direct + indirect = inclusive fitness
48
hamilton's inequality that summarizes the concept of inclusive fitness theory/when an inequality will be favoured
rB > C
r: degree of relatedness btwn two individuals
B: reproductive benefit to recipient
C: reproductive cost to actor
49
what can drive the evolution of altruism?
shared genes btwn relatives
50
relatedness
- probability that actor and recipient share gene in question
- depends on how genes were inherited
- i.e. gene tht leads actor to be altruistic
51
wht is our degree of relatedness to each parent? each full sibling?
- r = 0.5 to each parent
- r = 0.5 to each full sibling
- 50% chance each parent also passed gene down to ur sibling (0.5x0.5=0.25)
- 0.25 + 0.25 = 0.5 (bc two parents)
52
degree of relatedness to half siblings, aunts, and uncles?
r = 0.25
53
degree of relatedness to first cousin?
r = 0.125
54
what does Hamilton's rule tell us?
- theoretical adaptive behaviours
- helps us make predictions abt behavioural tendencies
55
why do some individuals in eusocial hymenoptera not reproduce?
- relatedness
- colonies founded by few individuals, so they are very close relatives
56
what else does relatedness in colonies also explain?
- levels of aggression btwn colonies
- i.e. argentine ants live in large colonies w/ several nests. aggression is higher when nests are less genetically similar (less shared alleles)
57
relatedness in cases of aggression/abuse in humans
homicide:
- 25% of homicides committed by relatives (but this included in-laws and bfs/gfs)
- 6% of homicides were committed byb GENETIC-relatives
child abuse:
- rates r higher amongst stepchildren than biological children
58
cinderella effect
- after socioeconomic status/family size/maternal age are accounted for
- stepchildren r victims of abuse more often than genetic offspring
59
in organisms w/ limited migration after sexual maturity, who is the kin?
- neighbours
- ppl who live close to u
- simple rule: be altruistic to ppl close to u, rather than needing a mechanism to recognize kin
60
how do parasitic species, like cuckoo birds, take advantage of the rule to treat close neighbours as kin?
- cuckoo birds lay their eggs in nests of other birds
- their eggs get taken care of by other birds
61
cues of kinship in humans
- mother's association (infants can distinguish mother by smell)
- co-residence with other children
- phenotype matching
62
which ground squirrels give the alarm calls when a predators comes nearby?
- females bc they stay in natal territory for life
- males disperse to establish their own territories
63
phenotype matching
- an evaluation of relatedness between individuals based on an assessment of phenotypical similarity
- btwn yourself and someone else = self-referential phenotype matching
- btwn someone else and a known family member
64
is phenotype matching necessarily a conscious decision?
no
65
DeBruine's Investment Game:
- 2 players
- player 1 doesn't trust player 2 = divide money equally ($4/2)
- player 1 trusts player 2 = player 2 divides money however they wish ($5)
- SO: player 1 can get more money by trusting player 2, and player 2 can get more money by betraying player 1
DeBruine predicted that individuals would exhibit more prosocial behaviours when interacting w/ people who resemble kin.
In experiment, player 2 was a computer generated strategy. Six rounds total. Player 1 saw pictures of either stranger of lookalike of kin.
What happened?
- players were more trusting of player 2 when player 2 resembled themselves
- thus, facial resemblance (form of phenotype matching) modulates behaviour in ways predicted by Hamilton's inclusive fitness theory
66
does inclusive fitness entirely explain altruistic behaviours?
- no
- we are also altruistic w/ ppl we know aren't our kin
67
why do we help those who don't look like us?
reciprocity
68
types of reciprocity
- direct reciprocity: individuals help each other, both benefit
- indirect reciprocity: when individuals help those who have helped others (helping = good reputation)
- people known to be selfish are often punished by others
69
when are people more generous/less likely to break rules?
when being observed by others
70
why does altruism exist?
- such pro social behaviours have been adaptive over evolutionary history
- wht is altruistic from individual's perspective is selfish from gene's perspective
71
do women prefer the scent of men who are genetically (MHC genes) similar or dissimilar to themselves?
- if on the pill: prefer genetically similar
- if naturally cycling: prefer genetically dissimilar
72
evolutionary theory
- our brains r a part of biology
- thus: brains nd behaviour r also subject to evolution
73
evidence for evolution
fossil record
74
what can fossil records be used to make?
phylogeny: pattern of evolutionary development of distinct lineage from common ancestors
75
what else can phylogenetic trees be constructed using?
- anatomical similarities in embryos prior to birth
- similarities in DNA sequences (transcribed or non-transcribed DNA)
76
is evolution fast or slow?
- usually slow
- “rapid” evolution of brain size in Homo took millions of years
- SOMETIMES: occurs fast in microorganisms
77
adaptive radiation
- the diversification of a group of organisms into forms to fill diff. ecological niches
- i.e. finches in galapagos became many types of finches (woodpecker/vampire) bc there were few animals that preceded it in galapagos
78
darwin’s term for evolution
descent by modification
79
does natural selection always lead to evolutionary change?
- no
- stabilizing selection happens when pop’s r well-adapted to their ecological niche
- changes only occur when necessary
80
heritable variants can be ____ or _____
physical or psychological
81
what is behaviour a combination of?
psychological mechanisms + input from environment
82
the prisoner’s dilemma
- 2 ppl rob a bank and hide money
- cops need someone to confess
- prisoner A and B can confess OR remain silent
- if they both remain silent, only go to prison for 1 year
- if one confesses, confesser gets no time and other gets 20 years
- if both confess, both go away for 5 years
when r we likeliest to be selfish?
more likely to be selfish if we know we won’t see other person again
83
which snacks r we likelier to eat? why?
- sweet/fatty/salty/protein ones
- i.e. we eat the wings before veggies
- we evolved during food scarcity, so sweet/salty/fatty gives us the nutrients we need
84
why do we prefer maternal grandmother over paternal grandfather?
- priori prediction: parental certainty directs bonding
- mothers are 100% sure that they are related to offspring, same with maternal grandmother (she knows grandkids are 100% genetically related to her)
- paternal grandfather hopes father is his child, and father hopes child is his child
- we love people who invest more time/resources into us AND ppl invest more into ppl they can guarantee are genetically related to them
85
what do women and men look for in romantic partners? why?
- women: possession of resources, qualities linked to resource acquisition (confidence), commitment
- men: youth, health, attractiveness
because:
- diff. selective pressures
- females have more metabolic demands in reproduction
- parental investment: males r investing more now BUT females still invest the most on time/energy basis
- genetic cuckoldry: females always know their kids r theirs but males can’t always know
86
romance in the friend zone: how is friendship perceived differently btwn men and women
are you attracted to your friend?
is ur friend attracted to u?
would u date ur friend?
- all were friends who never dated. diffs btwn men and women?
1.
women: no
men: yes
2.
women: no
men: yes
3.
women: no
men: yes
87
who is more likely to have a sexual overperception?
- males
- males don’t want to miss out
- males r likelier to think females r into them
88
outcome variance
- low variance: when most people do good bc mean is gathered in the centre (along x-axis)
- high variance: greater range in how ppl do (along x-axis)
89
kalahari-san: population that has natural fertility
what is the diff in reproduction btwn sexes?
- both have same mean of 2 kids
- females: 6.5 variance, so most females generally do good
- males: greater than 9 variance, some males do very bad and some do very good
90
which gender is likelier to take risks for social competition and material competition?
- men
- to meet reproductive element (outcome variance, men need the payoff)
- also likelier to engage in risky behaviour and murder
91
are you likelier to kill ppl if ur employed or unemployed?
- unemployed men
- peaks at 20-24
92
water flea, Daphnia magna
- engages in phototactic behaviour (when sun is visible, Daphnia sinks lower in water to avoid being spotted and eats when sun has set)
- likelier to act phototactically when water contains chemicals excreted by fish predators SO if sun is out but no chemicals, Daphnia will stay out
describe the study done with Daphnia
- phototactic behaviour evolves as a function at the risk of predation
- offspring laid from eggs that were laid when no fish chemicals were around responded less to light in presence of fish chemical cues
- offspring laid form eggs that were laid when fish chemicals were around responded more to light
- in presence of fish chemicals: Daphnia with genes that caused them to behave phototactically are likelier to survive/lay eggs
- no threat of predation: Daphnia without gene to behave phototactically are more likely to lay eggs
93
russell jackson/lawrence cormack: made a hypothesis about a psychological adaptation that humans have to protect us from height
wht was it?
- people overestimate vertical distance, and the overestimation increases as we go higher up and look down
- they proved tht to be true
- we do not overestimate distance horizontally
94
are adaptations perfect?
- no
- they just passed down bc they performed better than other traits
- environment can change
95
cues for fertility/quality
- fluctuating asymmetry: bilateral traits tht are symmetrical over a population, but not in an individual (higher symmetry = more desirable AND healthier)
- cues of health (i.e. symmetry)
- degree of femininity/masculinity
- waist-to-hip ratio (strongly sexually dimorphic) (waist divided by hip) (lower ratio = more fertile)
96
men vs. women about infidelity/jealousy
- men: more prone to sexual jealousy (desire to guard mate)
- women: more prone to romantic jealousy (prevent male from leaving and forming new relationship)
97
finn observed this abt the behaviour of men in a caribbean village (regarding jealousy)
men mated to fertile women (not pregnant but can become pregnant) = more conflict in relationship and w/ sexual rivals ESP if relationship isn’t sexually exclusive
98
how can sexual jealousy in men be dangerous?
- sexual jealousy is common motive for domestic violence
- adultery against husband is illegal, but not against women in many places
99
example in the real world of inclusive fitness:
- venezuela: Ye’Kwana
- individuals put in effort to tend to neighbour’s gardens
why?
positive correlation btwn amnt of help and degree of relatedness
100
social darwinism
- arose out of beliefs that natural selection is abt survival of the fittest
- used to justify colonialism, class division, and inbreeding
- NOT TRUE
- falls under naturalistic fallacy: assumption that natural = good/should be preserved
101
eugenics
- promotes selection of desired traits through constraints on reproduction
- current concern bc of prenatal screening and genetic testing
- we can’t rlly define desirable traits/violate human rights
102
cues of kinship: what is it called when older siblings learn to recognize younger siblings as the offspring of their mother? what abt younger recognizing older?
- older: maternal-perinatal association
- younger: co-residence duration
103
what does much evidence for maternal-perinatal association and co-residence duration come from?
- incest aversion
- aversion to mating w/ close relatives bc of kin recognition mechanisms
104
real world populations that avoid reproducing w/ people they were reared with
- israel: kibbutzim = community of infants cared for together, when adults, they almost never marry each other
- taiwan: ‘minor’ marriages where fams adopt a child as a future groom/bride for their own kid BUT the longer the child stayed, the likelier they were to divorce and the fewer children they produced
- since older sibling was there longer, they can ALSO use maternal-perinatal association as well as co-residence duration SOOOO older member is always averse regardless of how long they lived tgthr
105
is maternal-perinatal association or co-residence duration more powerful?
study:
- uni students asked abt aversion to sexual intercourse btwn siblings
- results?
- those who had older opposite-sex siblings: co-residence duration predicted their aversion
- those who had younger opposite-sex siblings were averse to the situation in general and co-residence duration did not further predict aversion
106
Triver’s parent-offspring conflict: competition for resources
- WE believe we are twice as valuable as our siblings from our point of view bc we have r=1 for ourselves and r=0.5 to siblings
- however, mother’s perspective is that she is most valuable and each sibling is equally valuable
- thus: maximizing parent fitness differs from what would maximize offspring fitness bc parents want to split evenly but offspring want to compete for more resources
107
triver’s parent-offspring conflict: an evolutionary arms race
- competition for fitness among offspring
- most fruitful in maternal-fetal interactions
- i.e. babies who beg louder may get more food, so all babies begin begging louder BUT THEN mother evolves to discount the signal
- as such, babies r wasting resources
psych 1xx3
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