Transcript Connecting Purpose, Brain, and Language: Understanding

Connecting Brain, Purpose &
Language:
Understanding Language
Behavior
as the Control of Perception
Gary A. Cziko
University of Illinois at Urbana-Champaign
[email protected]; garycziko.net
(start recording)
Apologies
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(5)
Not a brain or neuroscientist
Will not summarize or synthesize findings
from neural science
Theory and computer simulations I will
present are not my own (Wm. T. Powers)
Relativity little research has been done to
support theory and arguments I will
make
Don’t have fancy PowerPoint slides
Excuses
(3)
1. Am interested in biological bases of complex
human behavior: education & language
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Without Miracles (1995): Darwinian
The Things We Do (2000): Bernardian
2. Will share with you a fundamental building
block for understanding how mind might be
created from neurons
3. Will do some research, simulations and data
analysis with you to demonstrate some
behavioral phenomena and their possible
underlying neural basis
Goals of presentation
(4)
1. Explain how we can get human language from
neurons (in well under an hour!)
2. Provide a different perspective on behavior
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Neither behavioristic (S-R)
nor cognitive (S-O-R) (lineal A -> B causality)
Behavior as purposeful (circular causality)
3. Offer preliminary implications for
understanding language and its underlying
neural basis
4. How we might get mind from neurons
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From the simplest unit of perception, thought &
“Presence of mentality”
(read-along quote)
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“The pursuance of future ends and the
choice of means for their attainment are …
the mark and criterion of the presence of
mentality in a phenomenon. We impute no
mentality to sticks and stones, because they
never seem to move for the sake of anything,
but always when pushed, and then indifferently
and with no sign of choice. So we unhesitatingly
call them senseless.”
--Wm. James, 1890 (American psychologist)
Behavior demonstrating
“presence of mind”
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The rubber-band demo
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What is the subject doing?
Computerized RubberBand Demo
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Powers’ computer demo of
compensatory tracking (Demo 1; Step
F)
– Correlation between (visible) Cursor and
Handle (S-R)
– Correlation between (invisible)
Disturbance and Handle
Towards a model
(read-along quote)
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“What we have is a circuit, not an arc or
broken segment of a circle. This circuit is more
truly termed organic than reflex, because the
motor response determines the stimulus, just as
truly as sensory stimulus determines movement.
Indeed, the movement is only for the sake of
determining the stimulus, of fixing what kind of
a stimulus it is . . .”
--John Dewey, 1986 (American psychologist &
educator)
A model of
“compensatory tracking”
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Demo 2; Step G; “closing the loop”
– Explain components
– Behavior with open loop
– Close loop
– Vary reference level (purpose)
Step
 Continuously
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Characteristics of
Perceptual Control
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Provides a model of purposeful (intentional) behavior
– Internal reference level (goal, purpose, objective, intention) essential
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Perception (“stimulus”) affects behavior (“response”) AND behavior
affects perception
– Circular rather than lineal (one-way) causation
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Perceptual control shown by LOW correlation between perception
(“input”) and behavior (“output”)
– Test of the “controlled variable”
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Behavior understood as a means of controlling perception
– Not vice versa as in both behaviorism(S -> R) & cognitive psychology (S
-> O -> R)
– No clear “independent” or “dependent” variable
– Circular not straight line (lineal) causality
A Hierarchy of Perceptual Control
(3)
1. More complex behavior seen as control
of more complex perceptions
2. Inputs from lower-level perceptions
combined to form higher-level
perceptions
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not new, e.g, complex cells, neural nets
3. Outputs from higher levels sent to levels
as reference levels (goals, purpose)
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new
Demonstration of Hierarchy
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Volunteer maintains arm parallel to ground
Told to drop arm to side when hand pushed from
above
Predictions?
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Change in reference level from horizontal to vertical
Lower level will perceive push before upper level
perceives it and is able to change the reference level
for the lower system
Watch what happens!
The Whys and Hows of Behavior
(2)
1. Answers to “why” questions about
behavior found by going up to higherlevel perceptual control systems
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Why am I saying these sentences right now?
2. Answers to “how” questions about
behavior found by going down to lowerlevel perceptual control systems
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How am I saying these sentences right now?
Applications of PCT to Language
(4)
1. Language behavior is purposeful, intentional,
functional, goal-directed
2. Provides a social means of controlling one’s
perception
3. Language is hierarchical
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auditory intensities > phonetic features >
phonemes > morphemes > lexemes > phrases >
clauses > discourse
Hierarchy of control from articulation to pragmatics
4. Language behavior is usually successful
despite many disturbances (e.g.,
environmental noise; objects in mouth)
PCT provides a particular form of a
connectionist model (3)
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Circular perceptual control systems
arranged hierarchically
Neurons can compute (perceptrons) and
transmit information (senory and motor
systems)
Neurons can act as a comparators (using
inhibitory and excitatory synapses)
PCT provides an architecture for
research & discovery (4)
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Sensory (afferent) systems combining signals
from lower levels
Motor (efferent) systems sending reference
levels to lower-level comparators (desired
perceptions, not motor commands)
Comparators (comparing upper-level outputs
with lower-level inputs, with difference sent as
reference level to lower level)
Evidence of control: behavioral and neural
(controlled variable)
Conclusions
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Advances in neurosciences are providing
details at the micro level
An understanding of behavior as the
control of perception provides a macro
framework for understanding the microlevel details
Combining the two provides new
important insights into the connections
among brain, behavior, language and
human purposes
Resources
Powers, W. T. (1973). Behavior: The control of
perception. Chicago: Aldine de Gruyter.
 Gary Cziko’s books (full text online via
garycziko.net)
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– Without Miracles (1995)
– *The Things We Do (2000)
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Control Systems Group website:
– www.ed.uiuc.edu/csg (these & other computer
demos)
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Joel Walters (English, Bar-Ilan U)
– Application of PCT to understanding bilingualism
Connecting Purpose, Brain, and
Language:
Understanding Language
Behavior
as the Control of Perception
Gary A. Cziko
University of Illinois at Urbana-Champaign
[email protected]; garycziko.net
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“What we have is a circuit, not an arc or broken segment
of a circle. This circuit is more truly termed organic than
reflex, because the motor response determines the
stimulus, just as truly as sensory stimulus determines
movement. Indeed, the movement is only for the sake
of determining the stimulus, of fixing what kind of a
stimulus it is, of interpreting it.”(J. Dewey 1986, p. 353)
”It is possible to step back and treat the mind as one big
monster response function from the total environment
over the total past of the organism to future actions.“-Allen Newell (1998).
(Overview)
Introduction
 Demonstration & model of purposeful
behavior
 Hierarchies of perceptual control
 Applications to language
 Implications for neural science
 Resources for further exploration
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Demonstration & Model of
Perceptual Control (overview)
Rubber-band demo
 Powers’ computer demo of compensatory
tracking (Demo 1; Step F)
 Dewey quote
 Powers’ computer model of compensatory
tracking (Demo 2; Step G; “closing the
loop)
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