Connecting Brain, Purpose & Language: Understanding Language Behavior as the Control of Perception
Gary A. Cziko University of Illinois at Urbana-Champaign
g-cziko@uiuc.edu; garycziko.net
(start recording)
Apologies (5)
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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 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
• • Without Miracles (1995): Darwinian The Things We Do (2000): Bernardian
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
• From the simplest unit of perception, thought &
“Presence of mentality”
(read-along quote)
“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”
The rubber-band demo
What is the subject doing?
Computerized RubberBand Demo
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)
“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”
Demo 2; Step G; “closing the loop”
– Explain components – Behavior with open loop – Close loop – Vary reference level (purpose)
Step Continuously
Characteristics of Perceptual Control
Provides a model of purposeful (intentional) behavior
Perception (“stimulus”) affects behavior (“response”) AND behavior affects perception
Perceptual control shown by LOW correlation between perception (“input”) and behavior (“output”)
– Circular rather than lineal (one-way) causation – Test of the “controlled variable”
– Internal reference level (goal, purpose, objective, intention) essential
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
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1. More complex behavior seen as control of more complex perceptions 2. Inputs from lower-level perceptions combined to form higher-level perceptions
• not new, e.g, complex cells, neural nets
3. Outputs from higher levels sent to levels as reference levels (goals, purpose)
• new
Demonstration of Hierarchy
Volunteer maintains arm parallel to ground Told to drop arm to side when hand pushed from above Predictions?
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
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
• How am I saying these sentences right now?
Applications of PCT to Language
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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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4. Language behavior is usually successful despite many disturbances (e.g., environmental noise; objects in mouth)
auditory intensities > phonetic features > phonemes > morphemes > lexemes > phrases > clauses > discourse Hierarchy of control from articulation to pragmatics
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 (3)
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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)
Control Systems Group website:
– Without Miracles (1995) – *The Things We Do (2000)
Joel Walters (English, Bar-Ilan U)
– www.ed.uiuc.edu/csg (these & other computer demos)
– 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
g-cziko@uiuc.edu; garycziko.net
“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
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)