476 terms

Psyc 122 Final


Terms in this set (...)

Mechanisms of evolution:
Natural selection
Sexual selection
Gene flow
Founders effect
What is a theory?
A set of hypotheses that are falsifiable
Evolution is defined as:
a change in the genome of a population or organisms over generations
On the Origin of Species was not published for 20 years (1859) —> why?
-Understood the implications it would have on society
-Didn't want to be ostracized by his family
Alfred Russel Wallace
-naturalist at the same time of Darwin; though to be co-discoverer of natural selection
-Did not come from a wealthy family
-Inspired by Darwin and his writing
-Worked as a collector and sold specimens in order to fund exploration
Tenets of Selection
1. Variability in a trait across a population
2. Heritability of the trait —> has to be passed on to new generations
3. Differential reproductive success —> has to lead to this individual to have more babies than other members of the population
Natural Selection
operates on traits that increase the likelihood of individual survival
Peter and Rosemary Grant
-During the first half of the 70'd the islands received regular rainfall
-In 1977 there was a major draught with an 85% mortality of the species (massive selection event)
-How did the traits of the birds effect whether they survived or not? —> WHO SURVIVED AND WHY??
-All the birds left on the island were a lot bigger
-Only the bigger birds who could open the larger nuts survived
Sexual selection
-is the mechanism that Darwin arrived at when he tried to explain the conspicuous class of traits that defied explanation by ordinary natural selection for improved survival
-The traits are sexual differences
The classic main goal of the theory of sexual selection is
to explain the existence of such traits, the detailed mechanisms by which they are favored and their occurrence and variation among organisms
Sexual selection operates on
the traits that increase the likelihood of reproducing
Tenets of Selection are the _____ for both Natural Selection AND Sexual Selection
Intrasexual selection
competition between members of the same sex for access to mates
Intersexual Selection:
Choosing a mate
intrasexual selection is stronger on ______ while intersexual selection is stronger for ______
males; females
Bower Birds
Male bower birds build intricate bowers
Decorate in order to attract females
Fluctuating Asymmetries:
Deviations in the expression of symmetrical characteristic
Facial Symmetry
-Considered an attractive feature in humans
-Women are better at detecting small variances in symmetry
-Newborn infants will look at a symmetrical face over an asymmetrical one
Gene Flow
-The passive movement of genetic material from one population to another
- ex: Once a river between two populations, then drought, the it was reworked in someway and now the populations can interact in a way they weren't able to before
Mutations that are not deleterious typically manifest as
only small changes in the phenotype —> this effectively increases variability in the population, which selection can then act on
Founders Effect
-Occurs as a result of genetic separation of populations:
1. physical -- separation of species via islands
2. Cultural (amish)
Tungara Frog
-All the males start singing —> number of chucks various across individuals (use air-sacks to make noise)
-More Chucks = More Ladies
-So why don't they just chuck all the time?
BECAUSE the bats who eat frogs respond to the chucks to find them and eat them = BALANCEEEE!
he impetus for Darwin, Wallace & others to discover evolution by natural selection was specifically to answer the question of
why are there so many species
what is a species?
-historically, a species was defined as organisms that can interbreed and produce fertile offspring
biological species concept
a group of reproductively isolated organisms that produce reproductively viable offspring
reproductive isolation can occur through:
- behavior
- habitat
allopatric speciation
-a mode of speciation that occurs when biological populations of the same species become isolated from each other to an extent that prevents or interferes with genetic interchange.
- geographic barrier
parapatric speciation
-It occurs when populations are separated not by a geographical barrier, such as a body of water, but by an extreme change in habitat
- New niche
sympatric speciation
-the process through which new species evolve from a single ancestral species while inhabiting the same geographic region.
- Polymorphism occurs with single inhabitant and it spreads
What is the foundation of niche separation
reproductive isolation through behavior and habitat
the relative position of a population within a particular ecosystem
nonhuman primates of the Kibale forest, Uganda
- A bunch of similar species inhabit a single forest -- how?
- They all live in different ways, feed on different food, have different activity times and different social organizations
adaptive radiation
-the evolution of a single ancestral species into a diversity of species that each occupy an unique niche in an ecosystem
-the diversification of a group of organisms into forms filling different ecological niches.
ungulates: adaptive radiation example
-hoofed mammals
-3 african ungulate phylogenies
- Giraffe, rhino and elephants?
island biogeography
-the study of how species evolve in restricted, isolated habitats
-due to the restricted ecosystem and limited genetic pool, islands are typically associated with intense selection pressures
-historically, island biogeography research was specific to islands,
island biogeography: lemurs
- lemurs evolved in the absence of large land predators
- humans arrived ~2000 years ago and killed off all the largest species, including one the size of a gorilla
flores man
- in existence up to 10,000 years ago
- but stories of Ebu Gogo were told to Portugese sailers in 16th century
- miniaturization occurred on this island in other species, such as elephants
cognitive niche
-the evolution of a species niche includes its cognition
-factors such as the diet, activity time, sociality and mode of locomotion ultimately contribute to selection for cognitive mechanisms that enable individuals to navigate their respective worlds
major component of the primate niche
-social cognition
-primates have intricate social systems
cognitive niche: Dog example
-domesticated from wolves
-selection on their social cognition seems to have been to acutely attend to human social cues
-this suggests that the cognitive niche of dogs includes sensitivity to human social signals
oldest known primate
Plesiadis (60 mya)
- ~4mya
- walked bipedally
- about the size of a chimpanzee
- chimpanzee sized brain
adaptive radiation of Hominids
-from 3-5mya
- argues that cooking enabled easier digestion and an increase in the amount of nutrition, which provided the nutrients necessary for our larger brains
a species' niche includes
Ecological and cognitive factors
human speciation was driven by
a number of ecological factors, as well as utilizing a new high nutrient food source that supported larger brains
niko tinbergen
-there are 4 questions that must be studied in order to fully understand any ethological system
Function question
what is the behavior's utility? how does it impact survival?
Phylogeny Question
what other species also demonstrate the behavior?
Mechanism Question
what processes underlie the execution of the behavior?
Ontogeny Question
how does the behavior develop?
Function+Phylogeny are what kind of questions
Mechanism+Ontogeny are what kind of questions
Evolutionary History
Internal processes
Function of play in dogs: Motor Learning
- play fighting is one of the most common forms of play in dogs
- dominance and submission are not equal in play bouts. dogs tend to try to play with and dominate other dogs
-this type of play is likely functions for:

- developing fighting muscles and skills
- determining social dominance hierarchies
Function of play in dogs: Social Bonding
- dog play is biased to known individuals
- dog 'friendships' seem to be formed during play bouts (dog parks)
- the nature of play signals and interactions have a learned component that only occurs in a social setting
- dogs with little/no social contact with other dogs have difficulty bonding and playing with other dogs
- play functions as a setting in which to learn to interact with conspecifics
Function of play in dogs: Cognitive Development
- domestic dogs exhibit complex social cognition
- cooperative behaviors likely due to relatedness with wolves
- for example : hunting & play
- play functions to facilitate learning the appropriate usage and context of social signals
Phylogenetic Analysis
-is the cornerstone of the Ethology
- since behaviors do not fossilize, it allows us to use living animals to reconstruct evolutionary history
Shared Ancestry
-if a trait is present in 2 closely related species, it is considered to have a shared evolutionary ancestry
- the trait was present in the common ancestor
Derived Ancestry
-if a trait is present in 2 distantly related species, it is considered to have a derived evolutionary ancestry
-each species evolved the trait independently
- known as convergent evolution
Turtle Play
"object play"; pushing floating balls around
process of producing/perceiving the acoustic signal
communicating information/ideas through a medium (acoustic/gestural/etc)
mechanisms of speech production: Source
- air forced through the larynx
- vocal folds open/close -- source of pitch & harmonics
mechanisms of speech production Filter:
- movement of the tongue, mouth & lips serve to filter sound
- result of this filtering is formant frequencies
- formant frequencies are the primary acoustic cue used in speech
light analogy
spot light is the 'source' the windows are the 'filter'
Primary Mechanisms underlying speech production in humans and other mammals
-the source and filter
- each contributes to how speech in produced by our vocal apparatus
Outer Ear
Ear Drum
Tympanic Membrane
Middle Ear
Inner Ear
mechanisms of hearing
- sound travels into the outer ear and causes the tympanic membrane to vibrate - ossicles move at specific rates causing waves within the cochlea
Cochlea Specifics
- cochlea is a fluid filled structure that transmits sound waves
- hair cells in the organ of corti are tuned to specific frequencies
- high frequency hair cells at the entrance of the cochlea and low frequency is at the apex
- hair cells convert the sound wave into an action potential
once sound is converted to an action potential
it then transmits auditory information throughout the brain
Zebra Finch auditory learning is based on
tudor song
Zebra Finch Subsong Phase
beings sensory-motor learning (practice)
Zebra Finch Plastic Song Phase
the song structure begins to formalize
the ontogenetic development of birdsong
- a template for the song is first learned
- the structure of the song is crystallized through a system of sensory-motor feedback (practice)
- a final crystallized structure is ultimately reached at adulthood
attunement play
- the use of social signals (eye contact, smile, etc) to create a joint experience
- likely the first type of play
- evident in the first weeks of life
- this play 'attunes' individuals to each other
body play
- playing with body movements/motions
- similar to motor-learning play
- begins in infants (playing with arm/leg movements)
- very common in childhood and adolescence
- occurs in adulthood, but must be deliberate
object play
- playing with objects in the world
- begins in infants once they can grasp objects
- continues throughout life, but more common in childhood/adolescence
narrative play
- use story-telling to create a source of information
- young children enjoy being told stories - first-hand storytelling does not become common until later in childhood (~3-4 years)
- is frequently cited as the easiest way for children to learn
- persists for the rest of life for most people
imaginative play
- creating imaginary worlds, friends, etc
- does not become common until later in childhood (~2-3years)
- after 3, it is quite common
- persists for the rest of life for many people
social play
- engaging individuals in playful interactions
- does not become common until later in childhood (~2-3years)
- persists throughout life in one form or another
- some commonly cited subtypes:

- rough and tumble (play fighting)
- celebratory (e.g. birthday party, bachelor party, etc)
why is orgasm relevant to the study of behavior?
1) it is important to consider the evolutionary origins of human behaviors
2) mating/reproduction plays a enormous role in human psychology and biology both today and in our evolutionary history ...and orgasm certainly is significant in mating/reproduction
the female orgasm debate :
does female orgasm play a functional role in conception and/or another element of reproductive success, or is it a genetic biproduct of the male reproductive system?
stephen j gould
- Female orgasm = biproduct
-during embryonic development, the same organ becomes the penis in males and clitoris in females. therefore, the female orgasm is a biproduct of the nerve structure of this organ.
sarah hrdy
-Female orgasm = functional
-female orgasm is a complex and variable event. since orgasm occurs more often with particular males and at particular times of the ovulation cycle, it must play a functional role in determining which males' sperm are best for conceiving a child.
the climax of sexual intercourse characterized by the an intense sensation of pleasure
because male orgasm (ejaculation) is pleasurable,
individual will seek to engage in sex often, thus increasing the likelihood of reproduction
4 Functions of Orgasm
-facilitate conception by sperm retention
-facilitate pair bonding
-facilitate mate choice
-facilitate paternity certainty
Upsuck Hypothesis
- orgasm = sperm retention
-logic = the muscle contractions that occur during orgasm help to bring sperm closer to the eggs
Evidence Needed for Upsuck Hypothesis
(1) intercourse with female orgasm will have higher likelihood of conception
(2) women who orgasm more frequently will have more children
Baker & Bellis (1993)
- studied 32 women, found that orgasms that occurred between 1 min before to 45 after male ejaculation resulted in an increase in the amount of semen in the uterus
- although muscle contractions do occur during orgasms, the available data do not show that they aid in conception. nor do women who orgasm more frequently have more children
Orgasm Pair Bonding Hypothesis
- logic = achieving orgasm during intercourse creates a stronger bond between the individuals in the couple
Orgasm Pair Bonding Hypothesis Evidence Needed
(1) a close relationship between the frequency of orgasm and the type of relationship
(2) a symmetrical relationship between orgasm and strength of bonding
Problems with Pair Bonding hypothesis
con 1 - there is large discrepancy between intercourse and orgasm = - only ~20% of women report having regular orgasm from PVI - rate of intercourse and orgasm decrease over the longevity of relationship

con 2 - although a bond may occur, it may not be symmetrical - women produce the hormone oxytocin during orgasm - this hormone is known to be involved in imprinting/bonding - men do not produce this hormone
Orgasm Mate Choice Hypothesis
logic : orgasm will be achieved specifically with higher-quality men
Evidence Needed for Orgasm Mate Choice Hypothesis
women will have orgasms more often with men possessing high-quality traits than men possessing low quality traits
women report orgasm more frequently during intercourse with:
1. Symmetrical Men
2. Men with larger incomes
3. Extra-pair partner
Orgasm Paternity Confidence Hypothesis
logic - signals satisfaction to the male and makes the male be more certain of faithfulness
Evidence needed for Orgasm Paternity Confidence Hypothesis
(1) women who fake orgasm are more likely to seek out additional partners
(2) men will be more likely to invest in a child following intercourse with a woman who orgasms during intercourse
Which orgasm functions have the most evidence?
Function 3 = mate choice and Function 4 = paternity confidence
Female Orgasm Twin Study
- Spector et al. (2005) conducted a study of ~4000 women in England
- 1/2 identical twins
- 1/2 fraternal twins
- 34% of the variation in frequency of orgasm was inherited
Swedish Brown Trout Typical Mating Pattern
- the female digs a gravel pit for the eggs
- when she is ready to mate, she signals the male by opening her mouth and quivering
- a male comes and swims next to her and repeats the same behavior
- the male ejaculates & female then releases her eggs
-58% of the time, the female fakes it and does not release her eggs -- if she detects the male not to be good enough, she saves her eggs for a more suitable suitor
mechanism: male orgasm
stimulation of the penis results in rapid contractions of the sphincter, prostate and penile muscles which force sperm through the urethral opening (ejaculation)
mechanism: female orgasm
stimulation of the clitoris (& vagina) resulting in rhythmic contractions of the of the pelvic striated circumvaginal musculature, often with concomitant uterine and anal contractions
male orgasm functions
to drive males to pursue frequent sexual encounters
first orgasms typically occur during
early puberty or just prior
the primary function of recognizing food is to
determine which objects in the world are edible and provide sustenance
therefore we would expect that our ability to recognize food would be heavily influenced by
natural selection - traits that increase the likelihood of individual survival
Thompson's Gazelles
-stotting behavior
- healthier animals are able to stot higher
- healthy animals are better able to avoid predation
- predators should recognize this cue to determine who to attack
-failure to recognize this cue leads to unnecessary expenditure of energy
Examples of Avian Carnivores
1. Harpy Eagle
2. Crowned eagle
Examples of Mammal Carnivores
1. African Lion
2. Siberian Tiger
3. Polar Bear
White Fronted Capuchin Eating Category
- fruits, insects, small mammals, birds, bird eggs
Gorilla Eating Category
- Herbivorous
- Primarily planet materials
- Lowland gorillas consume large quantities of fruit due to availability
a precise system for food recognition is necessary because
of the dangers of recognition errors
although birds and mammals are separated by millions of years of evolution, each phylogenetic group recognizes
similar objects as food sources (fruit, insects, etc.)
Primate Diet Categories
- omnivory - frugivory - folivory - carnivory
salient features
-color texture shape size location smell
-depending on the species may be purely innate or require learning
Honey Bee mechanism of recognition
-Primary food: pollen & nectar
-looking for flowers
-Vision (ultraviolet)
Bats mechanism of recognition
-Primary food: flying insects
- audition (echolocation = bisonar)
- first discovered by Donald Griffin (1944)
- the animal produces a high-frequency pulse of sound and listens for the echo to determine the location of objects & prey
- the system is so precise, bats can recognize the type of insect from echolocation alone
- the primary salient feature is the wing flutter of the insect species
Shark Mechanism of Recognition
-Primary food: fish
- somatosensation (lateral line)
Lateral Line
- highly sensitive to environmental perturbations
- detects vibrations from movement in water
- may also detect electrical impulses and magnetic fields
Dogs mechanism of recognition
-Primary food: carnivores & other
- Olfaction
olfaction (vertebrates)
- receptors in the nasal epithelium detect molecules specific to particular smell
- dogs have ~100 times more receptors than humans
Types of social learning
-goal emulation
- appears in some form for most vertebrates species
Imitation :
when the sequence of motor actions and goal outcome are learned from a demonstrator and performed exactly the same way by an observer
goal emulation :
-the observer produces the same end result (goal) as the demonstrator but using a different, individual specific, motor pattern
-this contrasts with 'imitation' because although the same goal is achieved, a different motor pattern is employed
Rake Experiment
-demonstrator performed either the 'efficient' or 'less efficient' method
-then the rakes were given to the subjects (chimp or 2 yr old human)
- children imitated demonstrators method - chimpanzees used rakes to reach for food but employed a method independent of the demonstrator
teaching :
a demonstrator intentionally modifies its behavior in the presence of naive individual so as to facilitate their learning.
Caro & Hauser (1992) 'Necessary Conditions for Teaching'
(1) a teacher incurs some cost as a result of modifying its behavior when in the presence of naive animals
(2) the modified behavior of the teacher causes naive individuals to acquire some behavior more rapidly than they would otherwise
Food Timing Importance
knowing where and when food will be available is important for many animals who consume temporally and spatially varying foods
Sooty Mangabey Food Timing Example
-looking for figs
- ripe vs unripe fruit (have grubs inside)
-both mangabey species seem to have a spatial map of the fig trees in their range
-will travel directly to fruiting tree even when out of sight
-appear to be inspecting trees to test for ripeness of fruit and plan a later time to feed
hunting and prey recognition in cheetahs involves
social learning & salient features
stages of learning to hunt
1 - mothers pursue and knock down prey, wait for cubs to arrive before the final pursuit and kill
2 - carried live prey back to cubs, allow them to chase
3 - wound prey and allow cubs to make the final kill
types of prey pursued by cubs
- young : birds, lizards
- middle aged : larger birds, small carnivores (jackals), small mammals
- old : small carnivores, small & medium sized mammals
rhesus monkeys are able to live in a diversity of habitats because
they eat a diversity of food .... omnivorous
Rhesus Monkey preferred food
laurie santos experiment (rhesus monkey)
Condition 1:

1. displayed eating an apple
2. test = orange vs apple
3. result = bias to approach the same
4. conclusion = prefer "eaten" item

Condition 2:

1. Displayed eating red ball
2. blue cylinder vs red ball
3. result: bias to approach the same (color and shape)
4. conclusion = prefer eaten item

Condition 3:

1. Displayed tapping of red ball on ground
2. blue cylinder vs red ball
3. Result: no diff in approach behavior
4. conclusion: arbitrary action does not elicit the same behavioral response
Data suggest that monkeys use ____ to decide which item is food but only items placed in mouth are considered food
social learning
laurie santos experiment: Salient features specific
Condition 5a:

1. Displayed eating red ball
2. blue ball vs red ball
3. result: prefer same color

Condition 5b:

1. Displayed eating red ball
2. red cylinder vs red ball
3. Result: no difference in preference

Conclusion: monkeys attend to color over shape for 'eaten' items

Condition 6:

1. Displayed eating red ball
2. red cylinder (diff shape, same color) vs blue ball (same shape, diff color)
3. Result: prefer same color

Conclusion: monkeys attend to color over shape
laurie santos experiment Tools (not food)
Shape over color
laurie santos experiment on young monkeys
monkeys attend to color over shape independent of the type of action
______ was central to the potato washing behavior of Japanese macaques
social learning
rhesus seem to utilize ______ for food recognition
salient features and social learning
one of the most commonly cited reasons for going to a party is
to meet a potential significant (or insignificant) other
he primary function of a mate recognition system is to
identify a suitable individual with whom to reproduce (therefore we would expect that our ability to recognize mates would be heavily influenced by sexual selection - traits that increase the likelihood of reproducing )
why do we consider some individuals more attractive than others?
a relationship will exist between the traits that are perceived as 'attractive' and the traits that will likely increase an individual's reproductive success
reproductive success (RS):
effectively passing on one's own genes to a subsequent generation (includes both direct and indirect fitness)
all of your own offspring count at
direct fitness
because you share 1/2 of your DNA with siblings, you get ______ for each of their offspring
indirect fitness
classic view of mate recognition
-ideal male - provides good genes
-ideal female - provides willingness to mate
the function of male mate recognition
is to recognize available females
the function of female mate recognition
the function of female mate recognition
Function of mate recognition relates to reproductive success because :
1. a male + 3 females = 3 kids (quantity over quality)
2. a female + 3 males = 1 kid (quality over quantity)
the first step in mate recognition is
recognizing that the potential mate is a member of your own species
hat species look for in a mate is determined by
their mating system
polygyny :
- Type 1: Social Group: 1 male - multiple females

- Type 2: Social Group : multiple males - multiple females (potentially)

- Type 3: No Social Group/No Territory: [LEK] multiple males - multiple females
one female - multiple males
elephant seals relationship type
1. Polygyny Type 1
-intrasexual selection - males typically are physically much larger than females (50%) -intersexual selection - females prefer males based on size and ability to protect young
baboon relationship type
1. polygyny type 2
-intrasexual selection - males typically are physically larger than females (~30-40%)
-intersexual selection - females prefer males based position in the dominance hierarchy (higher ranking males receive more matings)
Monogamy Mammals vs birds
rare in mammals but fairly common in seasonal birds
Monogamy mate choice
Typically males display to females, and females choose a mate based on the salience of the display and territory quality
why mate with only a single female?
mate guarding : by staying with the female, the male can assure that he is the only one to mate with the female
mate assistance
mate assistance : the male provides parental care and helps the young survive
for most birds who practice polyandry, females prefer
for most birds who practice polyandry, females prefer a stable mate who provides - resources
- parental care
- territory defense
and an extra pair mate who provides:
- good genes
- more compatible genes
- additional resources
Gelada males are looking for
willing females + sometimes will adopt young female to mate with them during first estrus
Gelada females are looking for
protection from infanticidal males + predators
Dominant males looking for
willing females, expanded range
Subordinate Males looking for
isolated females
mating in the majority of taxonomic groups consists of:
1) male-male competition for access to females (intrasexual competition)
2) female choice (intersexual competition)
females possess mechanisms that allow them to
discriminate between the male variance; able to detect subtle differences in the meaningful 'attractive' male traits
There is a relationship between traits that are perceived as "attractive" and ....
traits that will likely increase an individual's reproductive success
handicap principle
in order for the signal to be reliable, it must be costly to the signaler - the signal must 'handicap' the signaler (classic example : male peacock )
logic of the signaler
'even though i am incurring this huge cost, i am so great that it does not affect me'
have crazy long tail feathers; the exaggeration of this trait only in males suggests that it is an important mate recognition cue
Mechanisms of female choice of males
visual - bright feathers
tactile - twelve wired bird of paradise?
acoustic- humpback whale songs
olfactory - smell
Humpback whale mating
- songs have been recorded at up to 2000 miles away, but can probably transmit further
- speculate that most whales in an ocean can hear each other
- the song changes (evolves) slowly over time
- males add novel elements to the song to attract females
canaries mating
- each breeding season, male canaries learn a new song
- females listen to the songs produced by males in an area
- choose based on song complexity & length
Grey Tree Frog mating
longer call = more likely to get female; this suggests that call duration is a reliable cue indicating good genes
baboon female mate choice
-although dominant males do receive a larger amount of matings, lower ranked males also receive some mating opportunities (why?)
- too many female's come into estrus at the same time for the dominant male mate with all of them
- baboons live in stable groups, meaning individuals develop long-term relationships
- males and females form 'friendships'
- females with male friends will often choose to mate with them during ovulation independent of the male's rank
waved albatross mating
- both males and females use the elaborate courtship dance to decide on a mate
- since both invest in young, both must be discriminating
sexual maturity in peacocks is marked by
the presence of the large iridescent feathers; usually takes 2-3 years to develop (signal of maturity)
sexual play in primates
- involves both males and females
- can include mounting with or without thrusting
- either sex can be in either position
- typically there is no penetration
in species with exclusive female choice, males tend
to evolve elaborate courtship displays
species with female and male choice for mating tend to require
two individuals for successful rearing of the young
- here both males and females often engage in some courtship ritual together
what a species is attracted to is related to their
mating system
modern humans mating system
'socially monogamous'
what percent of societies permit polygamy?
~ 75% of societies permit polygamy
sexual dimorphism of body size
the difference in size between the two sexes; avg height in US : men - 5'8", women - 5'3

more % dimorphism means more polyganous
testes size effect on mating
bigger testes means more females copulated with per ovulatory period
What percent of men and women cheat during marriage?
paternity uncertainty
several studies report 5-15% of children are not sired by their expected father
average age of men:
- People's Sexiest Man Alive since 1985 = 40
youngest: John F Kennedy Jr, 27
oldest: Sean Connery, 59
average age of women :
- People's Most Beautiful People 2009 = 27
- FHM 100 Sexiest Women 2009 = 26
- AskMen Hottest Women 2009 = 29
- Maxim Hot 100 2009 = 27
average age at first marriage has ____ overtime
women prefer men ____ in age
men prefer women ____ in age
who is our closest living phylogenetic relative?
chimps prefer ____ females
Why does chimps prefer older females?
live in a fission-fusion society with polygynous mating system; there is no paternal care or investment; older more experienced females are more likely to have offspring survive
age preference for younger females in humans may indicate
long-term investment in a particular mate and offspring
cues for peak fecundity are
primarily physical:
- facial symmetry
- youthful features: skin, breasts, lips, eyes
- low Waist-to-Hip Ratio (mostly independent of body mass)
WHR is an indicator of
reproductive health
-women with WHR around .7 become pregnant more easily and have better long term health
Lassek & Gaulin (2007)
- found a relationship between mothers WHR and intelligence of offspring
- mothers with WHR ~.7 had children who scored higher on cognitive tasks
cues for high-quality genes are mostly
physical, but not exclusively:
- facial symmetry
- musculature
- height (4-6" difference)
- intelligence
face symmetry
- is an accurate indicator of male health - shows good genes for fighting illness
alcohol consumption significantly impairs women's
ability to judge symmetry
traits valued in women for short term mating...
cues for peak fecundity are primarily physical:
- facial symmetry
- youthful features: skin, breasts, lips, eyes
- low Waist-to-Hip Ratio
traits valued in men for short term mating...
cues for high-quality genes are mostly physical, but not exclusively:
- facial symmetry
- musculature
- height (4-6" difference)
- intelligence
importance of physical appearance in partner:
men - 48% women - 19%
minimum desired earning capacity in partner:
men - 40th percentile
women - 70th percentile
traits valued in men for long term mating...
genes & resources
traits valued in women for long term mating...
overall fecundity & resources
women are more likely to cheat during
peak ovulation
- suggests a mixed strategy ...
- long-term partner provides resources - short-term partner provides good genes
classic thinking was that sexual attraction
- began with gonadarche (onset of puberty)
- growth of sex-specific gonads
- ~11 girls (ovaries)
- ~12 boys (testes)
- and was a quick development
sexual attraction
the subjective state of feelings of desire or fantasies about another person
early in development attraction is more of a
psychophysiological arousal, not sexual arousal & desire in the way adults experience it
Stages of Sexual Attraction Development: 10 yrs old
- first reports of sexual attraction & awareness
- commencement of andrenarche (adrenal development)
- increase in sex hormone production (androgen)
Stages of Sexual Attraction Development: 11-13 yrs old
- initial development of secondary sexual characteristics
- commencement of gonadarche
- some sexual arousal evident
Stages of Sexual Attraction Development: Adolescence
- continued physical/psychological sexual development
naturalistic fallacy
it is false to assume that what exists in nature is inherently right
is/ought distinction
just because this is what our biology tells us, does not mean we ought to behave that way
humans mating can be classified as
pair-bonding with moderate polygyny/extra pair matings
the function of mate recognition in humans is to
identify the features of individuals that correlate with both short-term and long-term mating strategies
phylogenetic evidence suggests that the age asymmetry in mate preference
may relate to paternal investment in offspring
Social Living Benefits
- more bodies: earlier detection of food and predators
- repeated interactions: increased opportunity for helping and reciprocity
- opportunity for cuckoldry
Social Living: More Bodies
-predator detection & defense
-an increase in the number of individuals means there are more individuals who can detect predators and defend against them
-find sparse food sources
Social Living: Repeated Interactions
-opportunities help & reciprocity
- the members of a cohesive social group have the opportunity for repeated interactions
- thus favors by one individual can be reciprocated
- reciprocal altruism (unrelated individuals)
- kin altruism (related individuals)
Reciprocal Altruism
- helping an unrelated individual may incur a cost, but the chance of it being reciprocated later provides a benefit
Kin Altruism
- helping a related individual may incur a cost, but because that individual is related the helper is increasing their inclusive fitness
chance for cuckoldry
-when multiple males and females live in a single social group the dominant animals are less able to co-opt all receptive females
-leaving mating opportunities for low ranking animals
-the benefit is for the low ranking males
Social Living Costs
- more bodies: easier detection by predators and increased competition for food (the more individuals in a group, the more mouths there are to feed)
- repeated interactions: increase chance for social deception and manipulation
- potential for cuckoldry
increased chance of deception and manipulation
repeated interactions with other group members provides opportunity to deceive and manipulate others by providing false information
vervet monkeys
- individuals will approach a subordinate to groom
- once the subordinate is relaxed, they will attack them
- similar behavior observed in other NHP species
- in a few small cases, low ranking vervets were observed to alarm call in the absence of a predator when near a preferred food source
increased chance of deception and manipulation experiment
- play 'leopard' alarm calls from individual A in the absence of the predator
- switch to 'leopard' alarm call from individual B - response increases
- switch to 'eagle' alarm call from individual A - response returns
african elephant
-during the mating season (musth), males fight for dominance and access to females
-the most dominant gets most of the mating, but it is difficult to control access to all females
-the cost here is to the dominant males
ultimately, selection on a species will find the
most beneficial balance between the costs and benefits of social organization
types of social organizations
- solitary
- communal
- eusocial
spends most time alone, unless mating
lives in a cohesive social group with constant interactions
share a common nest with division of labor, overlapping generations & cooperative care of young
example of solitary animal
Leopard and giant anteater
Example of communal animal
grey wolf and sociable weaver birds
sociable weaver birds
- a type of song bird
- live in groups of up to 400-500
example of eusocial
bugs, naked mole rat
Eusociality is defined as species that have:
1- reproductive division of labor
2- overlapping generations
3- cooperative care of young
all primates live in
communal social organizations
Pair-bonded social organization
Gibbons, marmosets, titi monkeys
Multi-male/female social organization
vervet monkeys, japanese macaques, yellow baboons
Harem social organization
gorillas, geladas, hamadryas baboons
Fission-Fusion organization
-Chimps, bonobos, spider monkeys
-the group will come together when high-quality food is abundant and separate when such food is sparse
critical mechanism for living in social groups
-mediating social interactions
- this is accomplished primarily with communication signals (visual, acoustic, olfactory)
- many species use a combination of all 3 sensory signaling pathways
waggle dance language
-Figure-eight-shaped waggle dance of the honeybee
-includes information about the direction and energy required to fly to the food goal
social coherence is maintained through a system of
social rules, which govern how individuals can interact
What is at the heart of social rules?
dominance hierarchy
dominance hierarchy
typically there a separate hierarchies for males and females
the chimpanzee male dominance hierarchy
- linear
- to reach the top, individuals must rise up using a combination of strength and social relationships
more dominant chimps can :
- take food from more subordinate animals
- receive grooming from subordinates, but never actually groom subordinates
- alpha male has priority to estrus females
Male bonobo dominance hierarchy
- linear, but less strict
-the society is highly matriarchal. a male's position in the hierarchy seems to be inherited from their mothers
More dominant bonobo's can
- lead the group to feeding areas
- grooming seems fairly symmetrical and rank independent
- alpha male has somewhat more priority to estrus females
Female baboon dominance hierarchy
-a strict linear matrilineal hierarchy
- when approaching a subordinate female, a dominant female (D) will produce a grunt, the subordinate female (S) will then produce a fear bark
Cheney&Seyfarth (1995)
-test whether baboons understood the social rules that governed the interactions of the group
- conducted playback experiment
- Dom grunt --> sub fear bark
- Sub grunt --> dom fear bark (more looking time)
- suggests that baboons understand not only the relative dominance of females, but the social rules that dictate the nature of their interactions
terrestrial herbaceous vegetation (THV)
-THV is present in the diets of both bonobos and chimpanzees
- is more abundant in bonobo habitat
- THV abundance is speculated to contribute to the differences in the social organizations of chimps and bonobos - less competition for food
how would two species, similar in size and diet evolve different social systems?
- Spider (social) v gibbons (monog)
- higher abundance of fruit in spider habitat
prey animals often have
high population densities
predators live at
low population densities
many of the animals in a social group are often
coefficient of relatedness (r)
- the percentage of genetic information shared between individuals
-offspring : r = .5
-siblings : r = .5
-grandparents : r = .25
-1st cousins : r = .125
individuals stand to increase their
inclusive fitness by helping those relatives
inclusive fitness
- the amount of direct fitness and indirect fitness that is the result of the individual's support
bees live in a
eusocial society
since only one female breeds, how can this benefit the individuals that do not?
-because males are clones, the DNA from the male chromosome will be identical for all individuals + 50% of of the DNA from the mother (r = .75 )
- even though do not have direct fitness, they have high inclusive fitness
male american bison (changing roles)
-stay with mother ~3 years
- leave group and join bachelor group - rise up in dominance
- during mating season, bachelor group will rejoin main herd, mate and defend the young from predators
female american bison (changing roles)
- stay with maternal group for life
- upon sexual maturity, begin mating and having offspring
- eventually take on leader role as age
how do adults perceive the changing role during ontogeny?
- adults are generally more permissive of young for wrong behaviors
- adults also seem aware that juvenile's are not always accurate
bonnet macaque
- alarm calls produced by adults elicit fleeing response
- alarm calls produced by juveniles elicit only a vigilance response
all societies have a social hierarchy structure often based on
sex-specific dominance
the ecological habitat of a species places a big constraint on
their social system as the amount and distribution of resources dictates the number of animals that can find food in a certain area
how individuals interact in society
changes over the course of their life
How many cheetahs worldwide?
around 14,000
Fastest land animal
- 0-65mph in 3s
- top speed ~75mph, but has been recorded at over 100mph
How much do cheetahs weigh?
80-125 pounds
How do cheetahs live socially?
sometimes in social groups, other times solitary
Cheetahs: Time in groups
mothers & cubs (months)
adolescent sibling groups (months) adult males (years)
male/female mating (days)
Cheetahs: Time Alone
pregnant females
single adolescents
single males
cooperative hunting
by hunting together, cheetahs can increase the size of the animals they are able to kill
hunting in cheetahs is ____ coordinated than in other felid species (lions)
predator defense in cheetahs
-multiple species prey on cheetah cubs. groups of cheetahs are more effective at avoiding predation than single animals
- mothers can sometimes defend cubs against potential intruders but their relatively small size makes it difficult
-- by 6-8months cubs can outrun lions and other predators
predator avoidance in cheetahs
-multiple species prey on cheetah cubs. groups of cheetahs are more effective at avoiding predation than single animals
-mother's vigilance also was affected by the number of cubs (as the # of cubs increased so did the amount of vigilance)
- coalitions are three times more likely to establish a stable territory
- this in large part was due to the greater number of animals who could fight with current residents
- single males do occasionally establish a territory, but it more likely the result of a vacancy
Cheetah Mating
- one type of short social groupings in cheetahs occurs during mating
- these associations may last from a few hours to a few days
Only feline to live in permanent social groups
American lion
-Extinct Phylogeny
- went extinct about 10,000 years ago - ranged from alaska to peru
- weighed double than of extant lions (1100lbs)
- largest cat to have ever lived
American Cheetah
-Extinct Phylogeny
- similar in body morphology to modern cheetahs
- but does not seem to be a close relative (convergent evolution)
- is argued to be the reason pronghorn antelopes run fast
Pride (of lions)
- 1-3 males
- these males are often related
- 5-6 females
- typically all related, but unrelated to males
- upon sexual maturity, males leave natal group
Nomads (lions)
often brothers travel together until they can displace resident males in a pride
coordinated hunting
- primarily performed by females
- each female plays distinct roles in the hunt
- males will sometimes participate for very large prey
- once kill is made, males dominate the carcass
defense against intruders experiment
- a set of playback experiments were conducted to test strategies for territory defense of lions
- Condition 1 = play roar of single male
- Condition 2 = roaring of 3 males
- Approach speaker in C1 but avoid in C2
Most common social groups in cheetahs
1. mother-cub groups
2. all male groups
kin altruism (in mother-cub)
- offspring contribute direct & inclusive fitness
- as cubs age, offset vigilance for predators and prey
- benefits outweigh costs
Social learning in mother-cub
impart knowledge of hunting technique & location
Social Signals in mother-cub
- olfactory signals - signal reproductive state of female

- visual signals - communicate information between mother&cubs: play

- acoustic signals - communicate information between mother&cubs: danger
Kin Altruism (all male group)
- coalitions tend to be brothers from same litter
- can aid each other in a host of tasks (hunting, defense, etc)
- increases indirect & inclusive fitness
ecology in all male groups
coalitions have the best permanent territories
Social Signals in all male groups
- olfactory signals - signal territory boundaries

- visual signals - communicate information between individuals : coordinate hunt

- acoustic signals - communicate information between individuals: presence of danger or prey
cheetah hunting behavior over time
- after 6mo, cubs accompany mothers on ~90% of hunts
- hunting behaviors increase linearly over time
mothers facilitate hunting
1 - mothers pursue and knock down prey, wait for cubs to arrive before the final pursuit and kill
2 - carried live prey back to cubs, allow them to chase
3 - wound prey and allow cubs to make the final kill
Cheetah vigilance over time
- cheetah cubs became incrementally more vigilant over time
- older cubs become more adept at sighting predators
social groups serve several functions, such as:
- cooperative hunting
- protection against predators (mother/cubs)
- establish a permanent territory (coalitions)
the mechanisms that underlie social living in cheetahs include
- genetics (relatedness)
- ecology
- social learning
living in a social group means interacting with
conspecifics on a regular basis
social success often means
-Being good at keeping track of relationships, social rules, previous interactions
-being good at each of these and knowing when to manipulate others knowledge
social cognition functions -
- monitor the actions of others
- maintain mental record of past interactions with conspecifics
- predict others' actions
- plan own actions based on short and long term social goals
- manipulate social setting
western scrub jay seed caching behavior
-seed caches are susceptible to pilfering
-when caching seeds, monitor whether other jays are around
-if other jays are present, will return later and re-cache seeds
Lioness social cognition
- lioness lives in same group whole life
- females are related (mother, sisters, etc)
- must know under what circumstances particular individuals are ok to interact with based on dominance, degree of relatedness
- with males, must know how to interact with them
Meerkat social cognition short term goals
- avoid predation --- stand sentry, participate in mobbing
- find mate --- appeasement behaviors
- form friendships --- appeasement behaviors
Meerkat social cognition long term goals
- achieve high status --- build friendship network
- increase reproductive success --- achieve high status
social tool use
- utilize individuals to reach particular goals
- instigate conflict between others
- build alliances to back rise in ranks
- scapegoat
tactical deception
'acts from the normal repertoire of the agent, deployed such that another individual is likely to misinterpret what the acts signify, to the advantage of the agent. '
types of tactical deception
- concealment
- distraction
- attraction
- creating an image
- use social tool
- deflection
social cognition contrasts with physical cognition because
it pertains to the ability to act on social events rather than physical objects
most examples of social cognition come from
studies of birds and mammals, with primates showing the most sophistication
a group of things defined by a set of shared observable properties/features
an abstract mental representation that is derived from specific examples and generalized to broader terms
social cognition categories
understanding of each relatedness would be individual family specific


these two are brothers because they have the same parents, i must experience how they as individuals will behave to predict their future behaviors
social cognition concepts
could generalize how a particular social type (i.e. brothers) are likely to behave


these two are brothers, therefore i predict that they will behave in a certain way because that is what 'brothers' generally do
dominance hierarchy social cognition
Transitive Inference (social cognition)
If A>B & B>C then A>C
defining an infinite statement using finite components
Who talks more: men or women?
women 2-3x more
social rank & volubility relationships
positive correlation
neurobiology of individual species is shaped by
selection for species-specific demands
encephalization quotient
brain size-body size ratio
Why have humans brains increased in size?
- seem to relate to an increase in social complexity and the respective cognitive demands (social group size is pos. corr. w brain size)
Theory of Mind
the ability to attribute mental states [beliefs, intentions, desires, knowledge, etc] to others. an ability to understand that other individuals can have mental states that are independent from their own.
when do children develop TOM
~4-5 years of age
data suggest that more communicative individuals may
achieve a higher social rank
David Premack & Guy Woodruff
- 1978 Does the chimpanzee have a theory of mind?
when the sequence of motor actions and goal outcome are learned from a demonstrator and performed exactly the same way by an observer
the competitive paradigm: Dominant-door
- Brian hare
- Dominant: retrieves jointly visible food then hidden food
- Subordinate: no food
The competitive paradigm: Door-Door
-Dominant: retrieves all food
-Subordinate: no food
The competitive paradigm: Subordinate
-Dominant: retrieves jointly visible food
- retrieves hidden food
what has been argued to be the precursor behavior to theory of mind?
gaze following
there was uncertainty about the social cognitive abilities of chimpanzees until
the competitive paradigm
mechanisms for social cognition in chimpanzees
imitation, cooperation and theory of mind
gaze following develops ____ in the chimp
Chimp cooperativeness _____ as they age
for communication to occur
1. a signal is emitted by one individual (signal producer) that can be
2. understood by a second individual (signal receiver)
communication functions to:
- elicit a particular behavior response in conspecifics
- provide conspecifics with shared information (cooperative)
- manipulate the actions of conspecifics (competitive)
Communication: cooperative context
- signal used to bond with individuals - warn conspecifics of danger
- provide important information for shared utility (good food source)
Communication: Competitive context
- provide false information
- attempt to elicit behavior that is harmful to receiver
- signal mate value to same-sex conspecifics
communication signals in each modality provide
distinct functional advantages
Communication Modalities: Visual
- temporally fast
- short time between signal/reception - signaler and receiver close
- small # of receivers
hippopotamus open mouth threat
functions to communicate threat and/or potential for fight
birds of paradise ornate plumage and ritualized dancing
functions to communicate genetic value for mating
Communication Modalities: Acoustic
- temporally fast
- short time between signal/reception - signaler and receiver close or separated
- can disguise location
- multiple receivers
white crowned sparrow song
functions to communicate mate value to females and as territory defense to males
hoolock gibbons song duets
functions to communicate to strengthen bond and as territory defense
Communication Modalities:
- temporally slow
- long time between signal/reception - signaler and receiver separated
- can disguise location
- multiple receivers
wolves scent marking
functions to communicate territory boundaries of pack
cheetah females pheromones
functions to communicate sexual receptiveness
every organism communicates with
males use visual signal to
-display size/strength to other males and defend a territory
- threat signals are used primarily to reduce the number of actual fights
- even if won, a fight can leave individuals injured and/or exhausted
many species employ vocalizations to
attract mates and repel intruders
acoustic communication is used to
coordinate social interactions and maintain group dynamics
Dolphin whistles
-produce individual signature
- conspecifics will match the structure of this whistle
- appears to function to engage the animals in vocal interactions
- whistles may act as individual's 'name'
how do returning penguin parents locate their chicks?
parents and offspring each produce an individually distinctive call that they use to find each other
how do ants know others are dead?
-when an ant dies, it excretes a chemical known as oleic acid
-when this chemical is smelled, ants will carry the carcass out of the colony
universal facial expressions
macaque monkeys open mouth threat
communicates threat and/or potential for fight
chimpanzee fear grimace
-communicates submission
-fear grimace is an evolutionary precursor to a smile
primate vocalizations are used to communicate:
- aggression
- appeasement
- bonding
- mating
- contact
- food
- predator
functional reference
- the vocalization communicates information about an object or event (referent) in the world that is independent of the acoustic structure of the call
common marmoset olfactory communication
scent mark to indicate territory and aid in reproductive suppression of subordinate females
women can judge facial symmetry/attractiveness of men by smell alone
Avian Signalar mechanism question
how is song produced?
Avian environment mechanism question
how is the signal transmitted effectively through this medium
Avian receiver mechanism question
how is song perceived and recognized?
avian syrinx
-air is expelled from the lungs and passes through the syrinx
-membranes are loosened/tightened to change the pitch
-each side of the syrinx works in coordination to produce notes
Avian song could only be interrupted
between syllables
songbirds are able to hear their song when they sing how does this affect song?
delayed auditory feedback
3 acoustic problems of signal transmission
1. degradation of signal
3.predator detection
degradation of signal
- recorded the songs of birds in each of these three habitats
- found that birds in the pitch of the songs correlated with the density of trees in the habitat
- lowest frequency pitch in dense forest birds
- highest frequency pitch in grassland birds
studies of forests with multiple species have found that they avoid interference by:

- being most active at different times of the day
- change pitch to avoid the same frequency used by other species
predator detection
-produce calls that acoustically difficult to localize
- tonal signals with little frequency modulation
Role of thalamus in hearing
- relay station between cortex and subcortical structures
- neurons show selective responses to birdsong
[inferior colliculus]
- early responses to complex acoustic features
- initial sensitivity to specific features of birdsong
primary auditory cortex]
- first stage of auditory processing in cortex
- complex responses to conspecific sounds (song and other vocalizations)
- recognition of key features
Auditory System
1. Cochlea
2. Cochlear Nucleus
3. MLd (inferior colliculus)
4. Ovoidalis (thalamus)
5. Field L (primary auditory cortex)
how do birds recognize that a sound is a song?
this occurs by recognizing a particular combination of acoustic features in the sound
swamp sparrow call recognition
-song consists of 6 different types of notes

-in new york populations, respond more strongly to their respective geographic variant than to the minnesota variant, and vice versa

-primary difference between the populations is in the prevalence of note types

- in NY, type 1 notes start the song, while type 6 notes end it

- the Minnesota population is the opposite
Swamp Sparrow call experiment
-an experiment tested whether birds perceived these differences as gradual or categorical
-found that sparrows perceive a categorical boundary between dialects
sensory exploitation
occasions when a novel feature is preferred due to a pre-existing sensory bias in receivers
swordtail fish sensory exploitation
-experiments show that females of species without a swordtail, prefer males that possess the trait
-this suggests that a pre-existing sensory bias existed prior to the evolution of the trait
tungara frog sensory exploitation
-papilla in the female ear showed a higher sensitivity to frequencies below the normal chuck
- could be exploited by males who produced calls in that range
how do young squirrels learn to respond correctly to snake alarm calls?
-playback of snake alarm calls to pups, showed that they responded more strongly when adults around them also responded
-pups not near adults showed little response
-it appears that the pups first are responding to the tension of adults, and later learn to associate that with particular alarm calls
vervet monkey communication ontogeny
-adults produce acoustically distinct alarm calls to 3 different predator classes: eagles, snakes and leopards
-how young vervets respond to these calls changes over early ontogeny
-initial response is to simply run to their mother, but they slowly learn the correct response (i.e. to look up in the sky in response to an eagle call)
-at first they produce an 'eagle' alarm call to any thing in the sky
-over the first year of life they refine their behavior to only produce an 'eagle' call when sighting a martial eagle.
ontogenetic changes occur in communication systems that are a function of
experience with conspecifics and the objects/events in the world
the primary function of language is to
communicate with conspecifics; language also functions as our medium for conceptual thought
- have no words for precise numbers
- words for 1, 2, many
- cannot count or perform math
a disorder in which there is an impairment in producing and/or comprehending spoken and/or written language
Broca's aphasia
pertains to impairments in language production
Wernicke's aphasia
pertains to impairments in language comprehension
Alfonso Caramazza and colleagues
- reported on Broca's aphasia patients with complementary deficits:

- in one study, one patient could produce vowels, but not consonants
- one patient could produce consonants, but not vowels

-in a second study, one patient could produce nouns, but not verbs
- one patient could produce verbs, but not nouns
vervet monkey alarm call system
- Each alarm call elicits a different behavioral response
- Eagle = look into sky
- Snake = survey the ground
- Cheetah = run into bush
are vocalizations that communicate a functional referent similar to words?
they differ in at least two important respects:

(1) referential vocalizations are natural signs of their referent (restricted contextual usage), while words are symbolic of their referent

(2) referential vocalizations can be learned through general associative learning, while words learning employs a more sophisticated learning mechanism (language acquisition)
Broca's Area
language production
wernicke's area
language comprehension
while broca's and wernicke's areas are involved in language processes,
(1) neither is an exclusive language area
(2) language engages many other areas of cortex
neural mechanisms underlying language has two pathways
1. Dorsal Pathway : sensory-motor integration
2. Ventral Pathway : sensory object integration with word meaning
- a philosophical approach arguing that all behaviors can be scientifically studied without recourse to internal psychological events (thoughts, concepts, minds, etc)
- approaches the study of behavior through conditioned learning
- dominated psychology until the 1950s
BF Skinner
-argued that all language learning could be explained through simple associative learning and imitation mechanisms
-thought that at birth, the mind is a 'blank slate'
noam chomsky
argued that Skinner's book was inadequate for explaining the more complex forms of language acquisition (grammar & syntax)
Chomsky's critiques
1. Poverty of the stimulus
2. constraints and principles cannot be learned
3. pattern of development is universal
poverty of the stimulus
- while children learn typically incomplete sentence inputs in their environment, they all produce grammatically correct sentences (generalization and extrapolation)
- can produce an infinite number of sentences from finite number of examples
constraints and principles cannot be learned
- children produce first word around 1year old, complete grammatical language 5-6
- at this age, they do not have the cognitive ability to understand the principles of grammar
- therefore, the process of learning language is guided by an innate learning mechanisms specific to this task
pattern of development is universal
- the course of language development is the same all around the world
- if children only learned what they were taught, there would be more variability
universal grammar
- the linguistics theory that certain core principles govern the acquisition of syntax
- parameters are innately specified and generalizable, but require experience
animal communication systems possess
potential evolutionary precursors for language, such as functionally referential calls and syntax, but both are qualitatively different from language and unlikely to be based on similar processes
tool use definition
the use of an external object as a functional extension of mouth, beak, hand, or claw, in the attainment of an immediate goal
social cognition
the encoding, storage, retrieval and processing of social information related to conspecifics
physical cognition
the encoding, storage, retrieval and processing of feature information related to objects
one key function of physical cognition
recognizing objects in the world
spatio-temporally bounded units in the world
a second function of physical cognition is
determining the causal relationships between objects in the world
albert michotte (1964)
- the first to examine the core principles of causality - investigated the temporal and spatial features that underlie our perception of causal events
understanding causal relationships between objects is
necessary for tool use, but not sufficient; one must understand that particular features of an object have a particular causal function
Woodpecker Finch physical cognition
use sticks to extract insects from inside trees
bottle nose dolphin sponge use
(1) hold it in their mouth as they swim along and stir up sand to make camouflaged fish try to flee
(2) wrap sponge around their mouth so they can stick their mouth is sharp coral or rock holes to forage for fish
california sea otters
place clam on their belly and use a stone to crack it open
orangutan physical cognition
- insect foraging
- spearing fish
- nest building
gorilla physical cognition
- using a stick to wade across a river
- rare instances of food procurement
- nest building
bonobo observed tool use
- leaf sponge
- nest building
- stone throwing
- vegetation seat
(no evidence of tool use for food procurement)
chimpanzee observed tool use
- termite fishing
- sticks to break apart termite mounds
- spears for hunting
- stone use (hammer/anvil/wedge)
- ball up leaves and use as sponges
- cleaning with 'sponges'
- throwing stones/sticks as weapons - nest building
jane goodall
- first observation of chimpanzee tool use in 1960
- ended the 'man the tool user' uniqueness argument
Tool Use Paradox
Bonobos, Gorillas and Orangutans exhibit little tool use in the wild, but extensive tool use in captivity
the more complex forms of physical cognition, such as tool use, are based on
the more general processes of object perception and causality
Most extensive tool user
Chimps; known to use tools in a diversity of contexts for both food procurement and other functions.
3 core principles of object perception
cohesion continuity contact
principle of cohesion.
a moving object maintains its connectedness and boundaries
Motion in violation with cohesion
1. connectedness (where they split)
2. Boundedness (where they come together)
principle of continuity.
a moving object traces exactly one connected path over space and time
principle of contact.
objects move together if and only if they touch
Tunnel Effect
the ability to track object spatial and feature information through occlusion
mechanisms underlying object perception
are not necessarily sensory specific
amodal completion
the perception of objects in the presence of occlusion in the absence of sensory information
by 12 months of age, children know
the nouns for the objects. this seems to facilitate object parsing
Caro & Hauser (1992) 'Necessary Conditions for Teaching'
(1) a teacher incurs some cost as a result of modifying its behavior when in the presence of naive animals
(2) the modified behavior of the teacher causes naive individuals to acquire some behavior more rapidly than they would otherwise
phonemic restoration is an example of
amodal completion in the auditory system
experiments with tamarins suggest that
an understanding of the causal relationship between features and outcome may be present even in species that do not use tools in the wild
the understanding of causal relationships underlying physical cognition appear to develop
early in nonhuman primates.
the function of physical cognition
to recognize objects in the world and their causal relationships
one area in which ravens excel is
understanding causal relationships
Raven meat experiment
-tied meat to the end of a string and tested how each individual solved problem to retrieve the food
- more than one strategy was used
- each individual appeared to solve the problem in a unique way
lots of bird species
Covids excel in
physical cognition and other cognitive processes
western scrub jay seed caching
- can have up to 2000-3000 seed caches
- 30,000 seeds
- will remember locations up to 6 months later
- even when buried under snow/leaves
Corvids also show tool use that
extends beyond what is observed in other Avian species
last common ancestor of mammals and birds
-was ~350MYA
- any similarities in cognition and behavior would be evidence of convergent evolution
the significant differences in neuroanatomy make the parallels between corvids and primates a
particularly interesting case of behavioral convergence and neural divergence over evolution
Human v pigeon shape recognition
humans and pigeons use the same relevant features of shapes for recognition
parsing objects in audition
- work by Prof. Tim Gentner (UCSD) indicates that starlings use the sequence of individual motifs in the song to recognize the individual identity of the caller
- this suggests that starlings are able to rapidly group different syllables into motifs (meaningful auditory objects)
Prof. Tim Gentner (UCSD)
- aimed to test the relationship between motifs and individual recognition

- Experiment 1 presented subjects with different numbers of motifs and tested subjects' ability to recognize the identity of the caller --> found that recognition increased with the number of motifs, but recognition could also occur with a relatively small number of motifs

- Experiment 2 masked different numbers of motifs with white noise and tested subjects' ability to recognize the identity of caller --> found that recognition declined with an increase in noise masking, but recognition was still possible with a relatively few number of motifs
mesopallium & nidopallium (cortex)
areas of the avian brain associated with higher level cognitive abilities - both are larger than expected in Corvids (particularly ravens and crows)
Level 1 Tool Use
- 1 object utilized for a goal
-example: twig for termite extraction
Level 2 Tool Use
- 2 objects utilized for a common goal
-example: usage of a hammer and anvil stone for cracking nuts
Level 3 Tool Use
- 3 objects utilized for a common goal
-example: usage of a hammer, wedge and anvil stone for cracking nuts
- chicks will imprint to
the most salient visual object are present at birth.
the chicks will show a preference to associate with
the imprinted object
Chicks show a preference for
self-propelled objects
how does object manipulation and tool use develop in ravens?
- an overall increase in this tool use behavior occurs
- most prevalent for 'tutored' birds
- although 'tutoring' seemed to help birds learn tool use, it was not necessary.
- isolated birds were able to learn the same tool use behaviors.
the mechanisms underlying physical cognition in ravens relate to their
ability to parse the world into meaningful units (objects) and causal reasoning
although isolated birds appear to develop tool using behaviors, the presence of a
tutor serves to facilitate this process