Brain Scans, Machine Learning, and Trillion-word Web Text Corpus

"The question of how the human brain represents conceptual knowledge has been debated in many scientific fields. Brain imaging studies have shown that different spatial patterns of neural activation are associated with thinking about different semantic categories of pictures and words (for example, tools, buildings, and animals). We present a computational model that predicts the functional magnetic resonance imaging (fMRI) neural activation associated with words for which fMRI data are not yet available. This model is trained via a combination of data from a trillion-word text corpus, and observed fMRI data associated with viewing several dozen concrete nouns. Once trained, the model predicts fMRI activation for thousands of other concrete nouns in the text corpus, with highly significant accuracies over the 60 nouns for which we currently have fMRI data."

Predicting Human Brain Activity Associated with the Meanings of Nouns, Tom M. Mitchell, Svetlana V. Shinkareva, Andrew Carlson, Kai-Min Chang, Vicente L. Malave, Robert A. Mason, Marcel Adam Just, Science, 320, pp. 1191-1195, May 30, 2008.

This research is the most interesting I have seen on the mapping of internal brain structure based on analysis of large bodies of text available from the web. When generating machine-learned models from fMRI data, they found that for their tested set of concrete nouns the most accurate intermediate semantic features were sensory-motor verbs. This matches with others theories of ideas being represented as the convergence of many related sensory patterns. For instance, apple as the convergence of the word "apple", redness, shiny, apple taste, apple texture, picking-by-hand, etc.

Laser Sound

This project is based on the Make Controller I picked up at Maker Faire. It plays tones controlled by the interruption of laser beams. The laser beams are from Laser Levels, and the MacBook software is implemented in the Processing environment.

Details here.

CUDA GPGPU on MacBook Pro Laptop

I've ported my pthread generic and CUDA GPGPU real-time ray tracers to Mac OS X running on a MacBook Pro laptop. It has a 2.4GHz Intel Core 2 Duo processor and a NVIDIA GeForce 9600M GT graphics processor. The Performance for 1 and 2 software threads is comparable to my older Linux desktop, and the CUDA is within a factor of 3 of the desktop graphics card.

Threads    Frames Per Second
1           8.5
2          17.4
GPU        16.7

TxtView Application for Android

I've written a simple Android application for viewing .txt files from Project Gutenberg. It is still under development.

APK and source available here.

Three Key Concepts, and Their Application

• Occam's Razor
  "the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory"
  


• Falsifiability
  "the logical possibility that an assertion can be shown false by an observation or a physical experiment"
  


• Uniformitarianism
  "the assumption that the natural processes operating in the past are the same as those that can be observed operating in the present"
  

These three concepts form part of the bedrock of the Western scientific method. When taken seriously, they help refute most supernatural claims. Science asserts that physical law has been constant over the time frames of the evolution of life on Earth, the evolution of man, and the development of civilization.

While we cannot travel into the past to directly witness historical events, we can examine evidence that has been (or should have been) left behind. We can also closely examine contemporaries, in both our own and other cultures, making similar claims. In the case of current supernatural claims, not one has held up to scientific examination.

Psychology carefully avoids making judgments about the truth of supernatural claims, instead focusing the individuals ability to function within their local social group. In Western society today we still see individuals making supernatural claims very similar to those we read in ancient texts. Sometimes they are recognized as mentally ill, but this does not stop others from believing and following them. From this it is easy to assume ancient, pre-scientific peoples were even more credulous.

This leaves one with several options on how to partition one's world-view. One extreme is to assert that many contemporary supernatural claims, from many traditions, are all true. A more moderate position is that the world was different two to four thousand years ago, and that supernatural claims from that time period were true. Of course these positions are often subdivided where claims within one tradition are uniformly true while the others are false (or misguided interpretations of events actually powered by the one true source).

The simplest Occam's-Razor explanation is to take a Uniformitarian position and assert that all supernatural claims for all time are purely based in psychology.

Galapagos

From Galapagos October 2008

Did the First Giraffe Have a Navel, Revisited

In an earlier post I asked, "Did the First Giraffe Have a Navel?". Turns out this is an old question:

These authors seem no more startled at a miraculous act of creation than at an ordinary birth. But do they really believe that at innumerable periods in the earth's history certain elemental atoms have been commanded suddenly to flash into living tissues? Do they believe that at each supposed act of creation one individual or many were produced? Were all the infinitely numerous kinds of animals and plants created as eggs or seed, or as full grown? and in the case of mammals, were they created bearing the false marks of nourishment from the mother's womb? The Origin of Species, By Charles Darwin (1859)