Slide#1
What have we learned about human knowledge by
studying its origins?
Slide#2
1. Cognition begins with domain-specific systems of core
knowledge
Foundations Of Mind:
--space
--objects
--persons
--numerosity
--language etc.
Conclusions and Questions
Each system works on a specific set of inputs
Each system performs a specific set of computations
Each system yields a specific set of representations
Experiments reveal the signatures of each system.
What have we learned about human knowledge by
studying its origins?
Slide#3
Phylogeny: The biological birth of the mind
2. Common signatures in human infants and in non-human animals
provide evidence that many core knowledge systems evolved
before humans, in ancestors common to humans and other
animals.
space perception: in every animal tested (e.g., visual cliff)
object perception: in human infants, monkeys, & chicks
geometric representations for navigation: in human
toddlers & rats
What have we learned about human knowledge by
studying its origins?
Slide#4
Phylogeny: The biological birth of the mind
Possible exceptions:
language: syntax and morphology are unique to humans
(speech perception & word segmentation are not)
joint attention and observational learning: aspects of
these abilities may be unique to humans.
disgust? moral sense?
large, approximate numerosity: in every animal tested
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What have we learned about human knowledge by
studying its origins?
Slide#5
Ontogeny: The developmental birth of the mind
object representations in infants and adult subitizing &
multiple-object tracking.
approximate numerosity in infants and adults
persons and goal-directed action in infants’ perception &
adults’ moral intuitions
Slide#7
Where infants and adults have a common set of core systems,
studies of infants can shed light on mature cognitive capacities.
Four reasons:
(1) Adults have amassed extensive knowledge; infant studies
reveal which aspects of this knowledge are most central.
(2) Adults can combine core representations together; infants
reveal the boundaries of different core systems.
(3) Adult knowledge reflects a mix of universal and culturespecific capacities. Infant studies suggest how to distinguish
these.
(4) Adult knowledge reflects a mix of rigid and flexible
capacities. Infant studies suggest how to distinguish these.
Slide#6
Because infants and adults share core knowledge systems, infants
can communicate with adults and learn from them:
3. Common signatures in human infants, children & adults provide
evidence that core knowledge systems persist over development.
The importance of studying infants
What have we learned about human knowledge by
studying its origins?
Word learning: complementary dispositions in infants and adults
--talk about objects at basic level
--rabbits, not undetached rabbit parts
--common assumptions about communication
Observational learning: tool use, rational action, learning about
food, snakes, moral taboos.
Successful learning requires a common set of concepts.
What have we learned about human knowledge by
studying its origins?
Slide#8
4. These Core Systems are the “Foundations” upon which the
mind is built.
Because our minds rest on these common Foundations, we can see
the ways in which our minds are the same:
Your mind is similar to other animal minds
Number
Space
Objects
Your mind is similar to an infant’s
Your mind is similar to the humans that built Stonehenge,
to aboriginal tribesmen
to a terrorist
to a homosexual (if you happen to be straight)
to the friend that you believe to be an enemy
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Slide#9
Conceptual change: going beyond core systems
Slide#10
Conceptual change: going beyond core systems
The capacity to go beyond core knowledge and combine together
distinct kinds of concepts may account, in part, for uniquely
human cognitive achievements:
From what we’ve seen, conceptual change is probably unique to
humans. (e.g. no number explosion for Ai the chimp)
Examples:
math & science
measurement & technology
economics & politics
law & explicit moral rules
cooking, baseball, movies, ….
What have we learned about human knowledge by
studying its origins?
Summary
1. Cognition begins with domain-specific systems of core
knowledge
2. Shared with animals
3. Shared with infants, and constant over development
4. Uniquely human concepts may arise by combining together
aspects of core representations to construct new concepts and
systems of concepts (“theories”).
--natural numbers
--left of the blue wall
Mechanisms of combination:
language (words & rules)
possibly others
Slide#11
Slide#12
A final, speculative question: Are core principles
always true and useful?
Some core principles aren’t strictly speaking true:
Euclidean geometry: false at large & (maybe) small scales
universe as non-euclidean?
sub-atomic space as >3 dimensional?
Object continuity & solidity: false at small scales
But: Core representations of space and objects are close-to-true at
the middle-sized scales at which we (mostly) reason: close enough
to be useful for navigation and commonsense physical reasoning.
Are there aspects of core knowledge that aren’t even close to being
true? That impair human cognition and action?
--could happen, if false core notions that were useful in early
human environments no longer are.
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Slide#13
Evidence for false and misleading core “knowledge”
systems?
Slide#14
Core “knowledge” of human kinds
Humans may have a core system for distinguishing among
different groups of humans as social partners and moral
patients.
The perceptual bases of the distinction may be open to variation
across cultures and history but include race, ethnicity, common
language and customs.
None.
At the core of this distinction may be the notion that members
of different groups that differ in their appearance and actions
also differ in their inward nature: their concepts, attitudes,
beliefs and values.
This notion may guide a spectrum of behaviors toward, and
inferences about, other people.
But let’s speculate.
This notion may be both false and harmful.
Slide#15
Is there a core belief in human kinds?
Hints from the past:
-hominid evolution: the notion of distinct human kinds was
true until c. 30,000 years ago, e.g. Homo Floresiensis
(Flores Man) lived 93,000 B.C. to 10,000 B.C; Neanderthal
Man (150,000 - 28,000 B.C.) had an average life span of forty
years, practiced burial rights and may have interbred with
homo sapien sapien.
-human prehistory: small groups, inter-group conflict
-human history: slavery, more inter-group conflicts
Hints from the present:
-Haidt/Rozin on universal emotions: ethics of community
(loyalty/fidelity to friend/family/group)
Slide#16
Is there a core belief in human kinds?
The thesis that humans have a core system for reasoning about
human kinds is an empirical claim: could be true or false; the
above hints are suggestive but not conclusive.
The thesis needs to be investigated, through all the kinds of
research we’ve discussed in this course.
--studies of infants
--studies of animals
--studies of cognitive development
--studies across cultures
--studies of mature brain & cognitive function
-current human events: ethnic wars and conflicts
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Does this belief have a basis in reality today?
Slide#17
Slide#18
Core Knowledge and Conceptual Change
Evidence from this course: Reports of human
differences are greatly exaggerated.
Suppose all this is true:
-Though differences exist, they are dwarfed by the commonalities
in concepts, beliefs, and values across all humans.
Examples of Universality:
(1) Natural language:
-- Universal Grammar
(2) Conceptions of space:
-- In/On vs. Tight Fit/Loose Fit
(3) Moral reasoning
-- Trolley problem intuitions, In-Group/Out-Group
A possible analogy from our understanding of the
universe
The visual cliff: core representations of supporting surfaces.
(a) Humans have a core system for reasoning about other humans
that leads us to categorize humans into different kinds and to
attribute fundamentally different beliefs and values to each kind.
(b) These concepts and beliefs are both false and harmful.
Would this be a hopeless situation? Would people be doomed to
pursue destructive and self-destructive inter-group conflicts?
A hope: The power of science and discovery to overturn our
incorrect beliefs about the world.
Slide#19
Slide#20
A possible analogy from cosmology
These core representations support a conception of the earth as flat.
Everyday experience seems to confirm this conception.
Children hold such conceptions.
--earth as a pancake
--earth as a hollow sphere
--etc.
The conceptions impair children’s learning about the shape of the
earth and the force of gravity.
Support from below.
Supporting surfaces are horizontal.
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Slide#21
Slide#22
Slide#23
Slide#24
A possible analogy from cosmology
A possible analogy from cosmology
By adulthood, however, everyone knows that the earth is round.
This knowledge is used in everyday life (planning trips, etc. etc.)
The flat earth concept is gone. Why does it go away?
Contradicted by 2500 years of scientific study.
Round earth is obvious from many, many centuries of
technological innovation:
e.g., marine exploration and navigation
telescopes, planes, satellites, …
A possible analogy from cosmology
Why are intuitive notions of human kinds still here?
Although questions about human nature and core knowledge have
a long history (Plato, Descartes, Helmholtz), direct experimental
studies of core knowledge are very recent (c. 50 years).
These studies have yet to spawn widely accepted insights or
innovations:
In our daily lives, the evident differences between people continue
to be very obvious; the underlying commonalities are less so.
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Slide#25
Slide#26
A parting hope
Foundations Of Mind
As we continue to study human knowledge and human nature, the
commonalities between all people will become more evident.
False conceptions of human subgroups that differ in their core
nature may be replaced by doing the science that reveals what we
all have in common.
The End
Thanks for a wonderful semester!
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