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Artificial Intelligence
PSY 152
5/17/2007
Preliminary Questions
• Will this material be on the test?– Yes.
• Is this material in the textbook?– No.
• Will you put these slides on the course website?– Yes, eventually.
http://psy.ucsd.edu/~jasonjones/sp07psyc152.html
• What if I have a question?– Ask now or come to my office hours.
Lecture Overview
• Why are we talking about AI in this class?
• What is AI?
• How do we know if an artifact is intelligent?
• How should we build intelligent systems?
• Is human intelligence exceptional?
Conceptions of Intelligence:Artificial Intelligence
Artificial Intelligence
• “the science and engineering of making intelligent machines”
• “the use of programs to enable machines to perform tasks which humans perform using their intelligence”
• “Multidisciplinary field encompassing computer science, neuroscience, philosophy, psychology, robotics, and linguistics, and devoted to the reproduction of the methods or results of human reasoning and brain activity”
Artificial Intelligence
• “A branch of computer science whose goal is the design of machines that have attributes associated with human intelligence, such as learning, reasoning, vision, understanding speech, and, ultimately, consciousness”
• “Computer software that can mimic the learning capability of a human”
• “An algorithm by which a computer gives the illusion of thinking like a human”
Artificial Intelligence
• Definition by consensus
• The endeavor to create artifacts that display behavior a reasonable person would describe as intelligent
Artificial Intelligence
• Definition by example– Defeating the best human chess players– Driving hundreds of miles through the desert
unaided– Parallel parking– Chatting in internet chatrooms– Examining x-rays for tumors
How do we know if an artifact is intelligent?
• The Turing Test
• A user chats with two unseen entities:– Human– A.I.
• The user must identify the human
Problems with the Turing Test
• The ability to converse is only a subset of intelligence
• Some humans would not pass the Turing Test– e.g. young children or illiterate adults
Demo
• Talking to Eliza:
• http://www-ai.ijs.si/eliza/eliza.html
When Eliza Worksyoung woman: Men are all alike.
eliza: In what way?
young woman: They're always bugging us about something specific or other.
eliza: Can you think of a specific example?
young woman: Well, my boyfriend made me come here.
eliza: Your boyfriend made you come here?
young woman: He says I'm depressed much of the time.
eliza: I am sorry to hear you are depressed.
young woman: It's true. I'm unhappy.
eliza: Do you think coming here will help you not to be unhappy?
young woman: I need some help, that much seems certain.
Demo
• Twenty questions
• Succeeds by limiting the scope of inquiry
How do we know if an artifact is intelligent?
• Deep Blue defeats Gary Kasparov
• First game won: February 10, 1996
• First match won: May 11, 1997
• Kasparov suspected humans were “coaching” Deep Blue
How do we know if an artifact is intelligent?
• Is your thermostat intelligent?• Is your dog intelligent?• When your alarm first goes off in the morning,
are you intelligent?
How do we know if an artifact is intelligent?
• Dichotomy vs. Continuum
• Dichotomy: Is this entity intelligent – yes or no
• Continuum: Where should we place this entity on the scale of possible intelligence
Rock
Calculator
ASIMO Robot
Cat
Dog Human
How do we know if an artifact is intelligent?
• Dichotomy vs. Continuum
• Dichotomy: Is this entity intelligent – yes or no
• Continuum: Where should we place this entity on the scale of possible intelligence
Rock
Calculator
ASIMO Robot
Cat
Dog Human
Your TA
How should we build intelligent systems?
Jacques de Vaucanson’s duck automaton1737
How should we build intelligent systems?
• Intelligence by design– Deep Blue does not play chess the way
humans play chess
• Intelligence by simulation– Neural networks
How should we build intelligent systems?
Build a system to calculate the exclusive or (XOR)
A xor B
Truth Table
A B A xor B
0 0 0
0 1 1
1 0 1
1 1 0
How should we build intelligent systems?
XOR Circuit XOR Neural Net
How should we build intelligent systems?
Design
Pros:• Design may be “whatever
works”• Can be directly inspired by
statistics, computer science and engineering
Cons:• The “AI Effect”• Designing intelligent systems
from scratch may be more difficult than copying existing systems
Simulation
Pros:• Learning about how the brain
may work is a byproduct• Can be directly inspired by
neuroscience and psychologyCons:• Limited to biologically plausible
approaches• Computational power needed
to simulate an intelligent system may exceed power needed to simply behave intelligently
Is human intelligence exceptional?
• Make and use tools
Is human intelligence exceptional?
• Self-aware
Is human intelligence exceptional?
• Use language to communicate
Is human intelligence exceptional?
• Defeating the best human chess players
• Driving hundreds of miles through the desert unaided
• Parallel parking
• Chatting in internet chatrooms
• Examining x-rays for tumors
Is human intelligence exceptional?
• The AI Effect – Whenever a feat of intelligence is accomplished by a man-made system, it is no longer seen as truly requiring intelligence.
"Every time we figure out a piece of it, it stops being magical; we say, Oh, that's just a computation."
Rodney Brooks
"As soon as someone gets a computer to do it, people say: 'That's not what we meant by intelligence.' People subconsciously are trying to preserve for themselves some special role in the universe."
Michael Kearns
Demo
• Class vs. Claude Shannon’s mindreader
• http://seed.ucsd.edu/~mindreader/
Is human intelligence exceptional?
Strong AI – It is possible for machines to truly reason, to represent and interact with the world and to become self aware.
Weak AI – The above is impossible or unattainable, and the focus should be on task-specific AI systems
Is human intelligence exceptional?
• The Chinese Room thought experiment– John Searle (1980)
Is human intelligence exceptional?
• Rebuttals to the Chinese Room– Perhaps the system as a whole can be said to
“understand” Chinese– Neurons don’t “understand” English
Is human intelligence exceptional?
• Computers will reach the processing speeds necessary to simulate brains within 30 years– Raymond Kurzweil
Is human intelligence exceptional?
• Kurzweil’s $10,000 bet that a computer will pass a rigorous form of Turing Test by 2029– http://www.longbets.org/1
Summary
• Intelligence is better thought of as a continuum rather than a dichotomy.– The range of human intelligence is a small subset of the range of
possible intelligences
• It remains an open question whether human intelligence is exceptional in kind or only in degree.
• Creating intelligent systems can be approached through design or through simulation.– A better understanding of the concept “intelligence” will follow
from both
Artificial Intelligence
PSY 152
5/17/2007
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