lecture 4 Flashcards
Dennett’s cognitive wheel
The fact that you can invent something that works does not guarantuee that you have learned something about nature.
Intelligence
Ability to deal with difficult and novel problems
o Adaptivity
o Very close to creativity
Time scales of adaptive behavior
- Extremely slow (evolutionary)
e.g., cuckoo - Slow (operant conditioning)
e.g., skinner box - Fast (problem solving)
intelligence
Think aloud protocols
Write down what people think during chess and replicate these processes
Drosophilia idea
o By building AI for chess, we hopefully learn how chessplayers think
o This failed.
why is chess difficult
- Explosion of possibilities (novel positions)
a. Combinatorial explosion - What is a good position?
simple problems
Problems for which the time to solve the problem does not increase fast when the problem becomes bigger
Polynomial time
hard problems
The solution times increases very fast
o Takes infinite amount of time
o Same with chess
Bc it checks all the positibilities
Non-polynomial time
If you solve one, you solve everything
classic AI solutions to solving problems
- Tree algorithms
- Evaluation function
- Build in a huge opening book
- End game table bases
Alpha-beta pruning
Stops evaluating a move when at least one possibility has been found that proves the move to be worse than a previously examined move
so they don’t follow the whole tree
this way they can go much deeper
deep blue
Hardware + 4 tricks (previously mentioned)
Kasparov lost against Deep Blue
is a cognitive wheel because this is not how humans solve problems/learn
Learning in AI
- Deep learning
a. Supervised and unsupervised learning
b. Neural networks - Reinforcement learning
a. Learn interations that are rewarded
Q learning
Fill out the q-table by randomly walking and sometimes it gets a reward. This creates the fastest pathway to the goal.
There is also exporation vs exploitation in these tables
Having sub goals also helps
Deep reinforcement learning
Q-table is replaced by deep learning NN that predicts next moves and learns from rewards
Monte Carlo Tree search
Start with random move and play out the game entirely with random moves
o Rollout
Do this multiple times and use average result to add values to moves A and B
When MCTS combined with deep reinforcement learning, it gives very powerful learning
> no evaluation of positions, just win/draw/loss at the end of a rollout