PROTO-HUMAN COGNITION IN NON-HUMAN ANIMALS

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PROTO-HUMAN COGNITION IN NON-HUMAN ANIMALS
James R Hurford Language Evolution and
Computation Research Unit, University of
Edinburgh
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Descartes Animals as automata, and humans as
automataReason Darwin Humans are evolutionarily
related to apes and all other animals. Morgan's
Canon In no case is an animal activity to be
interpreted in terms of higher psychological
processes, if it can be fairly interpreted in
terms of processes which stand lower in the scale
of psychological evolution and development.
Anthropomorphism versus continuity
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Seeds of language
precursors of aspects of language in animal life

• object permanence,
• episodic memory,
• metacognition,
• competence with abstract relations,
• transitive inference,
• subitizing,
• the where/what-dorsal/ventral separation,
• global and local attention.
• frame-of-reference' systems,

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Displaced reference Human language enables us to
refer to things distant in time and space. No
animal communication system allows the animal to
refer to distant things, (except
honeybee communication). But many animals can
solve object permanence tasks.
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Relative performance on object permanence
Species Visible/invisible How long?
Domestic chicks Neither
Squirrel monkeys Visible only
Cotton-top tamarins Both
Parrots Both
Dogs Both Up to 4 mins
Chimpanzees Both Overnight
Humans over 3 Both Very long times
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A solipsistic, private view of the origins of
reference. Private attention to objects (visible
or hidden) is the basis for later-evolved public
reference to objects (e.g. via language). Animals
abilities in object permanence tasks are the
evolutionary seed of displaced reference in
language.
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Episodic memory (mental time travel) Humans
describe specific events, often in the distant
past (or future). Tulving (and Suddendorf) claims
that episodic memory is unique to humans. But
there are degrees of episodic-like memory.
Episodic-like memory in animals is usually
restricted to the domains animals are interested
in (e.g. food).
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Clayton et al. Scrub jays remember where they
hid food, of what type and how long
before. Schwartz Evans apes have episodic-like
memory. MacDonald Gorillas could remember where
food was hidden 24 hours later. Schwartz the
gorilla King could remember the order in which he
had been given food items, 5 minutes apart.
(Backwards only!) Schwartz the gorilla King
could remember which of three possible events,
which had no lasting effect, he had seen up to 15
minutes earlier. Menzel The chimp Panzee could
remember the hiding of food several days later.
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Episodic memory a methodological problem Did
Panzee recall the hiding of food (episodic
memory) or where food lies hidden (semantic
memory)? How could we tell the difference? Humans
are inferentially promiscuous (Susan
Hurley) Possible experiment (1) Prominently show
a chimp a key being placed on a high shelf this
should be a salient event, but irrelevant (yet)
to the chimps normal life. (2) Later,
train the chimp to connect the key to the
unlocking of a food cupboard
(3) one day, appear to have
lost the key, and see if the chimp tells you it
is on the shelf.
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Metacognition Humans express propositional
attitudes to states of affairs. E.g.

I (dont) know/believe/think/hope that this
is correct. When an organism knows what it
knows, its actions are different from an organism
that is locked out of its library of knowledge
(Marc Hauser) Uncertainty monitoring Smith and
Washburn Pigeons and chimpanzees trained to
respond Yes, No or Dont know. The Dont
know response typically takes longer than the
more certain responses and is given at the
borderline between categories. Keddy-Hector et
al. Piglets backing out of a maze when they
realize they have made a wrong choice.
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Animals can represent abstract properties and
relations
Alex the parrot. What colour is this?
Red RED(x) COLOUR(RED) Whats same about
these? Shape. SQUARE(x), RED(x),
PLASTIC(x) SQUARE(y), BLUE(y),
WOOD(y) SQUARE(z), GREEN(z), GLASS(z) SHAPE(SQUA
RE)
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Animals can represent abstract properties and
relations
Relations between relations
SAME
DIFFERENT
DIFFERENT
DIFFERENT
DIFFERENT
SAME
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Animals can do transitive inference Baboon social
hierarchy (3160 possible pairs) (X dominates Y
Y dominates Z) X dominates Z Chickens
submit to a chicken who has beaten a chicken who
has beaten them.
Chickens challenge a chicken who was beaten by a
chicken they have beaten. Lab studies on
ordering A gt B gt C C gt D gt E
A gt G E
gt F gt G
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The magical number 4 (Nelson Cowan) Short-term
memory is limited to about 4 objects. Subitizing
collections of objects, up to about 4. Human
sentences are limited to about 3 participants
(subject, direct object, indirect object).
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Watch carefully how many stars are there?
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There is a psychological limit on perceivable
discrete numerosity around 4-5. Short-term memory
(Nelson
Cowan, The Magical Number 4) Many animals can
discriminate discrete numerosities up to about
3-4. (Stanislas Dehaene, The
Number Sense.)
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For any language, the maximum number of
obligatory noun phrases in any sentence (with any
verb) is 3. E.g. Mary awoke
(1 NP) Mary ate breakfast
(2 NPs) Mary put her keys on the
table (3 NPs)
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• A limit of four objects in visual working memory
  (Luck and Vogel, 1997)
• Mean short-term memory capacity in adults of 3-5
  chunks (Cowan, 2001)
• Deictic subsystems are limited to about three
  degrees of difference (e.g. Japanese ano, kono,
  sono).
• Minimal subscenes (Arbib) contain up to about
  four separate participants. The basic clauses of
  languages are adapted to describing such minimal
  subscenes.

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Animals (dont) have propositional
representations of the world Logically minimal
propositions
E
x LION(x) There is a lion

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• Many animals have simple predicate-argument
  structure.
• The most basic semantic distinction is between
  predicates and arguments PREDICATE (x).
• This asymmetric relation is the first sign of
  semantic structure.
• The innermost brackets in any complex semantic
  formula are those separating predicates from
  their arguments
• believe(john, ( x y (woman(x) man(y)
  love(x,y))))

E
A
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Many animals have simple predicate-argument
structure. A parallel between the
predicate-argument structure PREDICATE(x) and
distinct neural mechanisms for (i)
Attending to an arbitrary object - (x) -
(via the dorsal stream), (ii)
Categorizing an object - PREDICATE(x) -
(via the ventral stream).
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(z)
RED(z)
Dorsal stream locates object
Ventral stream categorizes object
(x)
(y)
(z)
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Posterior Parietal Cortex
Pulvinar
Superior Colliculus
Dorsal Stream
Lateral Geniculate Nucleus dorsalis
Primary Visual Cortex
Retina
Ventral Stream
Infero-temporal Cortex
(After Milner Goodale, 1995)
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... the most primitive contact that the visual
system makes with the world (the contact that
precedes the encoding of any sensory properties)
is a contact with what have been termed visual
objects or proto-objects ... As a result of the
deployment of focal attention, it becomes
possible to encode the various properties of the
visual objects, including their location, color,
shape and so on.'' (Pylyshyn (2000)206)
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• So, I am committed to one-place predicates as the
  basis for representations of scenes/objects/events
  in animals.
• How can at least some scenes/objects/events be
  represented solely in terms of one-place
  predicates?
• (More in my talk at 4.00pm.) But here I appeal
  to two psychological themes
• Global versus local attention
• Frame of Reference

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Global and local attention
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Quick global attention delivers something like
RED
YELLOW
PURPLE
DANCE
GIRL
SKIRT
GIRL
with predicates only approximately bound
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Global and local attention
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Another example
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Quick global attention delivers
KISS
GIRL
BOY
SMILE
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(No Transcript)
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Frame of Reference Judgements are made relative
to their contexts. E.g. What is judged as WHITE
in half-light is judged as GREY in full
light. Jokisch Troje (2003) Fast-striding
animals are seen as relatively small, and
slow-striding animals are judged to be relatively
big. Sarris (1998) Chickens can be trained to
make perceptual judgements such as big for a red
cube and small for a green cube.
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An iconic notation,
taking a cue from event semantics
KISS
AGENT BOY
PATIENT GIRL SMILE
Boxes correspond to individual variables, e, w,
x, y, z.
KISS(e)
AGENT(x)
BOY(x)
PATIENT(y) GIRL(y)
SMILE(y)
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An iconic notation,
taking a cue from event semantics
AGENT GIRL SMILE
Boxes correspond to individual variables, e, w,
x, y, z.
AGENT(y) GIRL(y) SMILE(y)
(No ontological distinction between a
one-participant event/state and an individual
object.)
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Thank you.