Sunday, December 19, 2004

Neocortex ratio

I'm reading a book called the The Tipping Point, by Malcolm Gladwell, who's basic premise is that ideas, behaviours, and products spread through social networks like viruses.

One of the interesting facts brought up in this book concerns the 'Neocortex Ratio', defined as the ratio of neocortex volume to the volume of the rest of the brain (i.e. total brain volume minus neocortex).

With a neocortex volume of 1006.5 cc and a total brain volume of 1251.8 cc (Stephan et al 1981), the neocortex ratio for humans is CR=4.1. This is about 50% larger than the maximum value for any other primate species (see Dunbar 1992a).

Dunbar believes that the neocortex ratio in primates is related to the size of their social groups and that intelligence evolved as a response to dealing with more complex social interactions. Dunbar found that the maximum effective social group size for humans is about 150. Several examples are cited, including the size of villages in hunter-gatherer societies, Amish villages, and military structures.

I think my neocortex ratio must be a little less than 4.1 based on my social group size. Hopefully I'm a little smarter (and more social) than the average gorilla. I predict if someone comes up with a non-invasive way to measure neocortex ratio, smart guys will pay big bucks to get sized up. Think about it...this could revolutionize the entire nerd dating scene. Instead of feeling inadequate about coming up short of the average 6, they could feel great about pulling out a studly 4.5.

Saturday, December 18, 2004

Word of the day: Qualia

I was thinking about 'identity' and 'time' (i.e. is a person at time t identical at time t+1?) and ran across this word on Wikipedia:

Qualia (singular: "quale") are most simply defined as the properties of sensory experiences [...] These properties are, by definition, epistemically unknowable in the absence of direct experience of them; as a result, they are also incommunicable.

Daniel Dennett identifies four properties which are commonly ascribed to qualia; that is, qualia are:

  • ineffable; that is, they cannot be communicated, or apprehended by any other means than direct experience.
  • intrinsic; that is, they are non-relational properties, which do not change depending on the experience's relation to other things.
  • private; that is, all interpersonal comparisons of qualia are systematically impossible.
  • directly or immediately apprehensible in consciousness; that is, to experience a quale is to know one experiences a quale, and to know all there is to know about that quale.

This is interesting given that some scientists look at information and the transfer of information (communication) as fundamental building blocks of the universe. If there are properties of the mind that are incommunicable, then maybe there is a building block missing?

Arguments for qualia:

In Frank Jackson’s “Epiphenomenal Qualia” (Jackson 1982), Jackson offers what he calls the “Knowledge Argument” for qualia. The clearest example of this argument runs as follows:
Mary the color scientist knows all the physical facts about color, including every physical fact about the experience of color in other people, from the behavior a particular color is likely to elicit to the specific sequence of neurological firings that register that a color has been seen. However, she has been confined from birth to a room that is black and white, and is only allowed to observe the outside world through a black and white monitor. When she is allowed to leave the room, it must be admitted that she learns something about the color red the first time she sees it specifically, she learns what it is like to see that color.

Arguments against:

Dennett , a physicalist, also has his own response to the "Mary the color scientist" thought experiment.
He argues that Mary would not, in fact, learn something new if she stepped out of her black and white room to see the color red. Dennett asserts that if she already truly knew "everything about color", that knowledge would include a deep understanding of why and how human neurology causes us to sense the "qualia" of color. Mary would therefore already know exactly what to expect of seeing red, before ever leaving the room. Dennett argues that although we cannot conceive of such a deep knowledge, if a premise of the thought experiment is that Mary knows all there is to know about color, we cannot assume that we can fathom or even describe such knowledge -- or that such knowledge doesn't exist.

This strikes me as a relevant thought experiment, since there has been some debate about "What Color is the Sky on Mars?". Can we ever know without standing on the surface of Mars and looking up?

Sunday, December 12, 2004

David Shrigley

I think this guy is brilliant. He's a little (well, maybe more than a little) twisted, but I laugh out loud at his simple, biting humor.

Here are a few of my favorites:
Who I am and what I want
What do you want?

Saturday, December 11, 2004

A Spacetime map

Spacetime is cool. An excerpt from the author, John A. Gowan:
" we look outward in space we look only backward in time. Because of the finite speed of light, we cannot look out in space into the present. We see our Universe not as it is, but as it used to be, in an ordered regression of spatial shells receding into the past as we look deeper into the heavens. Furthermore, the past Universe that we see from Earth is a unique subset of the whole past, as we cannot see any of our own history, and we see only single moments in the history of other parts of the Cosmos."

Thursday, December 09, 2004

Geometry of the Universe

The 5 Platonic Solids

The Greek philosopher Plato, who was born around 430 B.C., wrote about these five solids in a work called Timaeus. Historical accounts vary a little, but it is usually agreed that the solids themselves were discovered by the early Pythagoreans, perhaps by 450 B.C. There is evidence that the Egyptians knew about at least three of the solids; their work influenced the Pythagoreans.

In any case, Plato mentioned these solids in writing, and it was he who identified the solids with the elements commonly believed to make up all matter in the universe. In Plato's times, people believed that all things were made up of five different atoms. They were fire, air, water, earth, with the fifth being the cosmos (the universe itself).

Plato identified fire atoms with the tetrahedron, earth atoms with the cube, air atoms with the octahedron, water atoms with the icosahedron, and the cosmos atoms with the dodecahedron.

Who knew?

Edward Tufte has a sense of humor

Wednesday, December 08, 2004


Imagine standing on 161 images laid in a line on the floor. If you wanted to see only the first image followed by the last image, you would need to travel across the 160 images inbetween.

If you put the images on a 2D grid, say 12x14, you no longer need to travel as far to visit your next favorite, the worst case distance being about 18 images instead of 160.

If you arrange the images in a 3D grid (5x6x6) the worst case distance is only 8 images. In moving from a 1D organization to 3D organization, you have also increased the information content of the system. In 1D it took only one number to specify the location of an image, in 3D it takes three numbers per image.

If you assume you can travel at a constant rate of speed in all dimensions, then by reorganizing the space the images occupy (increasing information), you have also reduced the average time it takes to flit from one to another. Some scientists are now looking at information as one of the building blocks of the universe...matter, energy, information.

Superstring Theory postulates a 10 dimensional universe, with 4 dimensions of space-time and 6 shriveled, shrunken dimensions. Is it possible to somehow travel through these shrunken dimensions and end up on the other side of the universe? Does the quantum mechanism in our brain have access to these hidden dimensions? Is this how we make mental leaps…leaps of faith, jumps to conclusions, and spontaneous acts of creation?

At the origin all was still and balanced, then along came a quantum flux and the symmetry was broken. In our universe balance is dynamic, not absolute. You must shift your weight constantly to stay upright, afloat as it were, in air. The same imbalance that caused the big bang, the imperfection that causes supernova cycles of joining and explosion, also allows us to travel a non-linear path. We struggle to linearize our experiences, our reasoning of how we arrived from point A to point B, but such exercises are frustrated by our implicit non-linear nature.

We don’t dare trust non-linear forces like friction, which lets go of our feet at unseemly moments, causing us to stumble along like the physical analog of the thoughts that bump around in our head. Instead, we place our feet carefully, one after the other, directing ourselves on the shortest distance between two points, only to be smashed by the piano falling from the window.