Artificial Neural Networks

What are Neural Networks?

•  Models of the brain and nervous system
• Highly parallel 

               Process information much more like the brain than a serial computer

• Learning
• Very simple principles
• Very complex behaviors
• Applications

1.      As powerful problem solvers

2.      As biological models

Biological Neural Nets

Pigeons as art experts (Watanabe et al. 1995)

      Experiment:

• Pigeon in Skinner box

 

• Present paintings of two different artists (e.g. Chagall / Van Gogh)

 

• Reward for pecking when presented a particular artist (e.g. Van Gogh)

• Pigeons were able to discriminate between Van Gogh and Chagall with 95% accuracy (when presented with pictures they had been trained on)
• Discrimination still 85% successful for previously unseen paintings of the artists

• Pigeons do not simply memorise the pictures
• They can extract and recognise patterns (the ‘style’)
• They generalise from the already seen to make predictions

• This is what neural networks (biological and artificial) are good at (unlike conventional computer)

 

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