Hints of generality in machine learning

One of the themes in AI is the progressive replacement of hand crafted knowledge/programming with autonomous learning. Another theme is the progressive shift from narrow domain specific abilities to generally applicable performance. These themes are closely related: domain specific performance is usually achieved via encoding domain specific expert knowledge, provided by humans, into the AI itself. This encoding is fixed and static, and is potentially brittle if the agent is subjected to a domain outside its narrow region of applicability.

In this talk we see hints of generality in machine learning via the replacement of hand crafted, tuned features (as input to a later stage learning phase) with a learning phase that autonomously learns these features. Because domain specific features, for example for vision or speech recognition, are typically designed by subject matter experts, learning is constrained by that specific manual task. One cannot use vision features in an audio problem and so forth.

However, when machine learning is targeted at learning the features themselves (in an unsupervised scheme), the potential for generality becomes present. If features can be autonomously learned for various domains, the machine learning process becomes general in so far as the feature learning’s performance is comparable or superior to that using hand crafted knowledge. This is exactly what is demonstrated here.

And, to make it even more relevant in terms of current research avenues, this is related to findings in neuroscience that suggest the general applicability of some kinds of learning in the neocortex, where for example patients can learn to see with their auditory cortex or their somatosensory cortex (by rewiring the optic nerve). This suggests the possibility that there is a unique learning algorithm at work, at least in the learning of concepts at low levels of the hierarchy close to the perceptual level, which is exactly where features reside.

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