Learning in Brains and Machines (4): Episodic and Interactive Memory

Learning in Brains and Machines (4): Episodic and Interactive Memory
· Read in · 2080 words · All posts in series  · memory, like yours, exerts a powerful influence over my interaction with the world. It is reconstructive and evocative; I can easily form an image of hot December days in the South African summer, and remember my first time—it was morning on an Easter Sunday in April a few years ago—that I saw and felt snow. My ...

Learning in Brains and Machines (3): Synergistic and Modular Action 3

Learning in Brains and Machines (3): Synergistic and Modular Action
· Read in · 1796 words · All posts in series  ·  is a dance—precisely choreographed and executed—that we perform throughout our lives. This is the dance formed by our movements. Our movements are our actions and the final outcome of our decision making processes. Single actions are built into reusable sequences, sequences are composed into complex routines, routines are arranged into elegant choreographies, and so the complexity of ...

Learning in Brains and Machines (1): Temporal Differences 9

Learning in Brains and Machines (1): Temporal Differences
· Read in · 1800 words · collected posts · We all make mistakes, and as is often said, only then can we learn. Our mistakes allow us to gain insight, and the ability to make better judgements and fewer mistakes in future. In their influential paper, the neuroscientists Robert Rescorla and Allan Wagner put this more succinctly, 'organisms only ...

Machine Learning Trick of the Day (5): Log Derivative Trick 8

Machine Learning Trick of the Day (5): Log Derivative Trick
Machine learning involves manipulating probabilities. These probabilities are most often represented as normalised-probabilities or as log-probabilities. An ability to shrewdly alternate between these two representations is a vital step towards strengthening the probabilistic dexterity we need to solve modern machine learning problems. Today's trick, the log derivative trick, helps us to do just this, using the property of the derivative of the logarithm. This ...

Machine Learning Trick of the Day (4): Reparameterisation Tricks 5

Machine Learning Trick of the Day (4): Reparameterisation Tricks
Our ability to rewrite statistical problems in an equivalent but different form, to reparameterise them, is one of the most general-purpose tools we have in mathematical statistics. We used reparameterisation in all the tricks we explored in this series so far: trick 1 re-expressed a log-partition function in terms of copies (replicas) of the marginal probability, trick 2 re-expressed a ...