Soccer

• http://youtube.com/watch?v=ICgL1OWsn58

• http://youtube.com/watch?v=N8Q15Uc-Ygo

• http://youtube.com/watch?v=1JJsBFiXGl0

CIS 197Computers in Society

Professor John Peterson

Quiz Recap

How does IBM make money with free software?

Contrast ODF and OOXMLWhat’s a Turing machine?What is Lady Lovelace’s objection?

How does it relate to the chess articles?

Why doesn’t Dennett believe people will consider Deep Blue intelligent?

Slashdot Time

Watch out for Chinese Hackers!

Reading Assignments

For Thursday, the reading is from Wikipedia.

It’s a little dense but make sure you get the basic ideas clear before class Thursday.

Poker

• Did the poker programmers need a special “super computer” to play a good game of poker?

• Why would poker be harder to play than chess?

• What is notable about the computer strategy in checkers?

• Why are researchers interested in poker?

• What poker game does Polaris play?

Poker

• What was the format of the tournament?

• What key aspect of poker was missing?

• What is a “bot”?• What did the human players think of

the computer opponent?

Soccer

• What sort of players did the CMU team field in robot soccer?

• What is the stated goal of the robot soccer movement?

• What is the biggest problem facing the robots?

• Can humanoid robots move with the same agility as humans?

• Should we fear a robot rebellion?

Artificial Intelligence

What is it?What might it be?Drew McDermott

The Brain As a Computer

• The brain is made up of billions of neurons

• A neuron is a cell that can send signals to its neighbors

• The signals depend on inputs from its neighbors

• Ultimately, input from senses, output to muscles

What If Each NeuronIs Computing Something?

Examples:• Visual cortex: Some neurons match

up images from left and right eyes and compute the disparities --- the differences in depth

• Hippocampus: In mice, some neurons become more active when mouse is in a particular place (computing degree of match)

Where is the Mind?

Brain Mind

Do some neurons have “invisible inputs”?

Is the brain nothing but a

computer?

Cognitive Science

• An alliance of disciplines: psychology, philosophy, linguistics, neuroscience, computer science

• All dedicated to exploring computational models of mind*

*Within each field, not everyone is a

“computationalist” about mind --- yet.

AI

• Within CS, AI is the subdiscipline that attacks very hard problems using empirical methods.

• We try algorithms and see how they work.

• Alas, we have no general theory of intelligence. We have theories about language processing, speech recognition, game playing, plan creation and execution, robotics, vision, inference, ….

AI Is Not Psychology

• Computationalism in psychology is known as cognitive psychology.

• It differs from AI in that it is looking for verification that people’s brains actually compute what their models say they could compute.

• It’s less concerned with the details of the models.

• Experiments with people vs. experiments with computers.

Computer Vision

• How do you get from an image to recognition of an object or a person, or control of object manipulation?

• An image is an array of numbers (recording light levels). (Compare retinas.)

• Vision feels easy --- it’s not.

Place Recognition

Where was this taken?

Remember: We’re

comparing arrays of numbers.No two

images are

exactly the

same.

Solution:

• Adjust for light levels• Adjust for scale (zoom)• Find the point where the sum of

differences of light levels is minimal; if low enough, report “I’ve been here before!”

Computer Chess

• The best programs can beat almost every human player

• They do it by searching through game trees

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

Minimax Algorithm

• Assign numbers to ending positions (“leaves” of the game tree): 1 if I (computer) win, -1 if I lose, 0 if draw

• For other nodes of tree, assign number of minimal child at opponent’s nodes, maximal child at my nodes

• Choose move with highest number

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

1

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

1

1

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

1

1 1

1

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

1

1 1

1

-1

0

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

1

1 1

1

-1

0

0

x

xo

o

x

xo

o x

xo

o

x

x

x

xo

o

x

x

xo

o

xoo

x

xo

o

xox

x

xo

oxo

x

xo

oxo

x

X

X X

OO

Tic-tac-toe Game Tree

1

1 1

1

-1

0

0

1

Big Amendment

• In real games, like chess, we can’t look all the way to the end of the game.

• So we cut the tree off after a few moves, and use a heuristic evaluation algorithm to estimate how good the position is based on board features (e.g., how many rows I have two of my marks in vs. how many such rows opponent has).

• Then apply minimax to pass numbers up.

Real Intelligence?

• Are all the separate subfields of AI going to achieve real computer intelligence?

• Right now, it depends on what the target turns out to be. People think their minds are single entities with general skills, but we’re discovering more and more specialized modules in the brain.

• Genius is rare and perhaps unpredictable

Computer Consciousness

• When they build an “artificial nose,” can it really experience the smell of garlic? Does it know what turpentine smells like? Would it have the same experiences we have?

• Answer: It wouldn’t experience anything!

But…

• When we know exactly how information flows through the brain, will we conclude that we can’t experience anything?

• Guess: Consciousness will turn out to be a matter of modeling oneself as having experiences.

The Self-Modeling Nose

• Suppose the nose is connected to a robot that can make inferences about what it thought it smelled and what was probably there.

• It must distinguish between appearance and reality. Appearance in this case is “the way things seem to smell.” At this point it’s helpful to have the concept of “odor”

Qualia

• We know what “red” looks like, and how it differs from “green.” But there’s nothing much else to say.

• The brain’s theory of itself stops with these ultimate qualia of things because it has to stop! Robots will have to do the same thing (although the details will differ a lot).

Don’t Get the Wrong Idea…

Most AI people hate to talk about consciousness. It’s too fuzzy.

This is not what the field is about.

It’s about algorithms and experimentation.

Summary

• The brain computes things• Perhaps that’s all it does• Cognitive science explores this

hypothesis• AI is the branch that explores

algorithms for difficult computational problems

• If cognitive science succeeds, it may even explain consciousness