10/23/12 1 Discovery: Psychopaths have 11% less prefrontal volume than healthy subjects. Conclusions? What should we conclude regarding the biology of criminal behavior?
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Discovery: Psychopaths have 11% less prefrontal volume than healthy subjects.
Conclusions? What should we conclude regarding the biology of criminal behavior?
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what is it for?
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what is it for?
the case of the sea squirt
Tadpole phase w/ brain Sessile adult
phase w/out brain
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Mind = software
computational metaphor
Brain = hardware
Brain/mind as: 1- information processor 2- represents the world 3- predictive engine
TRAIT YES NO modularity x cell types x neurochemistry x size x laterality x size-function relations x interfaces between modules x symbolic representations x abstraction from sensation/percept x recursive/combinatorial operations x
uniquely human brain?
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a. functional specialization 1. phylogenetic patterns
2. adaptive design
outline
b. size
a. ecological pressures b. social pressures
3. development
Neurochemical
Neurons Cortical Regions/lobes
Inter-cortical connections
Psychological states
the brain’s mechanisms
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comparative brain evolution
Motor
AuditorySomatosensory
Vision
Space Planning, decision
parietal
occipital temporal
frontal
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granny cells
modularity & swiss army knives:
Danook shows off his swiss army knife
Fodor Tooby & Cosmides
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Domain-specific Fast, automatic processing
Dedicated neural architecture
Characteristic breakdown
Informationally encapsulated
signatures of a module
a face module • fast, automatic
• domain-specific
• informationally encapsulated
• dedicated architecture
• characteristic breakdown
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prosopagnosia:
questions & main points:
Q: what other systems of the brain might be modular?
Q: what systems of the brain are most certainly NOT modular?
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a. functional specialization 1. phylogenetic patterns
2. adaptive design
outline
b. size
a. ecological pressures b. social pressures
3. development
comparative size differences
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Log (Body Weight)
Log (Brain Weight)
1g 10 kg 100,000kg.01g
100kg
Primates/DolphinsOther MammalsSmarter???
brain size: comparative differences
“No one, I presume, doubts that the large proportion which the the size of man’s brain bears to his body, compared to the same proportion in the gorilla or orang, is closely connected with his higher mental powers… On the other hand, no one supposes that the intellect of any two animals or of any two men can be accurately gauged by the cubic contents of their skulls.”
C. Darwin, 1871
hominidae brain evolution
brain capacity (cubic centimeters)
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unlocking the genes thru microcephaly
hominid brain evolution: size again
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Brain size fallacies
BIG brain
SMALL body
Selection The Chihuahua Fallacy
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decreases in brain size
dec. inc. mix
phylogenetic changes in brain size
smaller brains
larger brains
only animal eaters
implications of domestication studies : • selection on X can lead to other, unanticipated changes
• targeted selection can lead to extremely fast evolution
• domestication in humans?
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questions & main points: • Q: why do we plot the relationship between brain and body size?
• Q: what can we infer about the increase in brain size over hominid evolution?
• Q: selection can cause both increases and decreases in brain size. this reflects important aspects of the species’ ecology and social environment.
a. functional specialization 1. phylogenetic patterns
2. adaptive design
outline
b. size
a. ecological pressures b. social pressures
3. development
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our approach
Problems of mechanism can be tackled in isolation, but are best carried out as solutions to adaptive problems. Adaptive solutions are always designed in light of mechanistic constraints.
How microchiropteran bats capture prey
design of a predator’s brain:
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Bat biosonar
100 300
Frequency (Hertz)
SoundPressureLevel(dB)
0
100 Best frequency
neural tuning curves:
Sound Pressure
Level (dB)
Frequency (Hertz)
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co-evolutionary arms races:
Howler monkeys-folivores Spider monkeys-frugivores
ecology & brain design
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questions & main points: • Q: tamarins specialize on insects, marmosets on sap. what would you expect in terms of neural/cognitive specializations?
• brain design is a reflection of social and ecological factors
• due to these socioecological pressures, two distantly related species may have more similarly structured brains than two closely related species living in different environments.
a. functional specialization 1. phylogenetic patterns
2. adaptive design
outline
b. size
a. ecological pressures b. social pressures
3. development
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how mating systems select for sex differences in spatial ability
brain design for spatial memory:
Hippocampus
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Meadow & Prairie
Polygamous Monogamous
voles
Female boundaries
Male boundaries
Typical polygamous mammal
Typical monogamous mammal
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Average day range (meter2) 0 1000
Polygamous meadow voles
Monogamous prairie voles
Female
Male
Female
Male
home range, mating system, & sex diffs:
Maze performance
Prairie voles (monog.): No sex differences
Meadow voles (polyg.): Sex differences -- Males faster
mating system & maze running:
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hippocampus: a key area for memory
Hippocampal volume (mm ) 0 35
Polygamous meadow voles
Monogamous prairie voles
3
Female
Male
Female
Male
hippocampal volume
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comparative applications
Food caching (storing) birds
Parasitic cuckoo birds
Log [Avg. Group Size]
0
100
0 10 Neocortex ratio prosimians
monogamous anthropoids
polygamous anthropoids
hominoids
social life & brain size
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Environment of Evolutionary Adaptedness (EEA)
Hunter-gatherers as windows into our past, and especially, the kinds of social and ecological problems that we faced.
the hyper-social brain:
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questions & main points: • Q: among humans, what careers might favor greater spatial ability, and would this be evident from the neuroanatomy?
• selection for both overall brain size and particular specializations, based on socioecology and experience
a. functional specialization 1. phylogenetic patterns
2. adaptive design
outline
b. size
a. ecological pressures b. social pressures
3. development
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Extreme nurture: blank slates & silly putty
Let us then suppose the mind to be, as we say, white paper void of all characters, without any ideas. Whence comes it by that vast store which the busy and boundless fancy of man has painted on it with almost endless variety? Whence has it all the materials of reason and knowledge? To this I answer, in one word, from EXPERIENCE. John Locke
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1. Innate = fixed, experience irrelevant
2. Innate = universal
3. Innate = early onset
false inferences about nativism:
4. Animal behavior = instinctive; Human behavior = learned
the undebatable issues: • Account for the processes that take a fertilized egg
to some end state in adulthood, replete with species-typical capacities
• The starting state must entail certain genetic givens --- some endowment that has evolved to provide each species with its unique signature
• What mechanisms channel the relevant experiences to cause change over development?
• How is experience mapped into changes in the neural circuitry, to cause stable changes in perception and knowledge of the world?
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Level ofSkill
Onset ofExperience
normal environment
added experience
developmental path-1:
Level ofSkill
Onset ofExperience
developmental path-2:
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Level ofSkill
Onset ofExperience
developmental path-3:
Level ofSkill
Onset ofExperience
developmental path-4:
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Level ofSkill
Onset ofExperience
developmental path-5:
Magnitudeof Trait
Low
High
1 NEnvironments
norm of reaction:
Norm of reaction: the extent to which a genotype exhibits phenotypic variation in different environments.
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Thinking about others’ thoughts
a theory of mind (ToM):
• Eye direction detector (at birth?)
• Shared attention/seeing-knowing (14 mos)
• Pretense (18-24mos)
• Appearance-reality (3 yrs)
• Personal beliefs & desires (3 yrs)
• Intentionality detector (14 mos)
• False beliefs (4 yrs)
• Beliefs about beliefs about beliefs (>5yrs)
Ontogeny of ToM:
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This is Sally This is Anne
Sally puts her ball in the basket
Sally goes away
Anne moves the ball to her box
Where will Sally look for her ball?
Sally & Anne: understanding false beliefs
Does the chimpanzee have a ToM?
D. Premack Sarah
D. Povinelli self-recog seeing-knowing
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Hare et al. (2000, 2001)
Perspective: seeing as knowing
Flombaum & Santos, 2005
seeing as knowing: rhesus monkeys
#Subjects
25
0
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autism and mindblindess:
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Temple Grandin By MARC HAUSER Thursday, Apr. 29, 2010
BACK N
What do neurologists, cattle and McDonald's have in common? They all owe a great deal to one woman, a renowned animal scientist born with autism, Temple Grandin. Though she didn't utter a word until close to her fourth birthday, substituting screams for phonemes, she splashed onto the stage of public awareness in 1995, thanks to the vivid, sensitive writing of the famed neurologist Oliver Sacks. Little was known about autism at the time except that people so afflicted appeared socially isolated, emotionally fragile and difficult to engage. But as with many psychological disorders, autism is a spectrum, and Temple, 62, is on one edge. Living on this edge has allowed her to be an extraordinary source of inspiration for autistic children, their parents — and all people. She is also a source of hope for another mammal: the cow. Using her unique window into the minds of animals, she has developed corrals for cattle that improve their quality of life by reducing stress. And though the fast-food industry continues to use cattle in its patties, it has come to appreciate the ethics and compassion of a Grandin burger.
The 2010 TIME 100
Stephen Wiltshire: Autistic savant
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motion primitives:
Autistics can properly interpret perceptual events (e.g., seeing), but not mental states (e.g., wanting, believing).
seeing vs wanting: perception vs mental states
Johnny
Which one is Johnny looking at?
Which one does Johnny want?
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emotional & imitative deficits:
Autistics have difficulty with self-reflective, social emotions (empathy)
Autistics have difficulty with imitation
mirror neurons:
Mirror neurons fire both when a macaque monkey acts in a particular way and when this same individual watches someone else acting in the same way.
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questions & main points: • Q: what is the hardware vs software distinction in light of the computational metaphor?
• many conserved neurophysiological features
• a small set of uniquely human neurocognitive features generative comp; symbols, interfaces, abstract
• domain-specificity and adaptations for particular cognitive problems
• ecological and social pressures and neural design
• fallacies of brain size
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