I went to a talk by David MacKay today on distributed phase codes for associative memories. One of his demos used a program called Dasher, which is a text entry system with a novel interface that could be used by disabled people. It’s baffling at first, but I imagine it becomes quite intuitive after a while. There are some demos on the website — it’s definitely worth checking out.

As far as the talk went, I have to admit I was a little lost, since everything I know about Hebbian learning and associative memories could fit on a 4×6 index card, probably. The main point of the talk was that utilizing inter-neuron spike times (or phases) and coincidence detectors that look for spatiotemporal spike pattens (with given delays) can produce structures that learn several patterns within the same neurons and can recall multiple patterns simultaneously. It’s an interesting idea, but the presentation was math-poor, so I ended up with very little idea about the “pattern capacity” of these memories, the effects of noise (and how it was modeled). These prosaic engineering questions weren’t really the focus of the talk, however, but maybe I’ll do the back-of-the-envelope calculations later.

top 100 novels revisited

I recently looked at the Modern Library’s 100 Best Novels list again, and noticed an addition that wasn’t there before. It’s the top 100 list as selected by “readers.” Just glancing at the top 10 gives us some insight into the nature of these readers:

3. BATTLEFIELD EARTH by L. Ron Hubbard
4. THE LORD OF THE RINGS by J.R.R. Tolkien
6. 1984 by George Orwell
7. ANTHEM by Ayn Rand
8. WE THE LIVING by Ayn Rand
9. MISSION EARTH by L. Ron Hubbard
10. FEAR by L. Ron Hubbard

The readers, it seems, are mainly Objectivists and Scientologists (read: nutcases). The sci-fi selections get better farther down the list, but Ender’s Game makes a surprise appearance at number 59. I never read it in middle school, but I don’t think it really would have resonated with me then. Reading it when I was 22 was like listening to a Linkin Park song on repeat for 3 hours. Oh so painful.

The whole thing kind of resembles the reading list that the MIT Extropians sent to everyone in my entering class at MIT. Some juicy excerpts can be read in Geeta‘s Village Voice article on the Larry Summers debacle. Ah, those were the days.