Models Of The Brain Flashcards
Symbolic logic
Creating new knowledge from facts already known -> replace all words with symbols and can make same inference
1970s blocks world
“Put small red block on top of the blue block”
Known= green pyramid on top of small red block, green medium block on top of big red block
Inferences= small red block is blocked by green pyramid, move green pyramid to free space
1990s chess
Known= white rook on A1, white queen on D1
Inferences= white knight can take black pawn, black bishop can take …
Conditioning
Before = unconditioned stimulus (U) strong connections to response (R)
After = conditioned stimulus (C) strengthened connections to unconditioned stimulus (U)
Cognitive machine
Can do reasoning, learning, perception
Data-analysis model
Data driven
Purely descriptive
Box and arrow model
Information processing model
Conceptual, implicit assumptions
Computational model
Information processing model implemented as a simulation
Explicit assumptions
Various levels of abstractions
Explicit vs implicit
Epstein (2008)
When studying cognitive processes, always employ models, often implicit
Computational models make assumptions explicitly
Assumptions can then be tested
Prediction
Epstein (2008)
A computational model can give specific predictions for the outcome of an experiment
Helps select which experiments to perform
Helps distinguish between different plausible models
Explanation
Epstein (2008)
Models can be explanatory even if they are not predictive
Eg computational models of schizophrenia indicate causes without being able to predict individual cases
Abstraction and idealisation
Abstracted and idealised models can capture broad trends
David Marr
Level of understanding
1) computation -> why (problem)
What is the goal of computation? Why is it appropriate? Logic behind it?
2) algorithm -> what (rules)
How can computational theory be executed? Algorithm, data, representation
3)implementation -> how (physical)
How can representation and algorithm be realised physically?
Bottom up approach
Implementation
->
Rules
->
Problem
Top down approach
Problem
->
Rules
->
Implementation