Update: Joi’s post about this.

While I’m all for public interest in science, especially neuroscience, its a pity when undecided questions are reported as solved.

The issue in question is one of the neural coding of semantic information. Jason and the New Scientist article he links to describe what is known as the Grandmother Cell theory. In short, the theory argues that most distinct semantic concepts each have their own dedicated neuron which fires when we access that concept.

The problem with this theory, despite the fact that our brains are never actually this simple, is that there simply aren’t enough neurons in the right areas to encode all the possible content we might encounter. What would happen when we run out of neurons?

An alternative to the Grandmother Cell theory is the Distributed Representation theory (also called a neural network), which argues that semantic content is encoded by the specific structure of connections between neurons. This, to me, sounds much more reasonable. Realistically though (and as seemingly suggested in the article, though they don’t outright say it) is that our brains probably work in a way that combines the two theories.

Although I don’t fly nearly as often as some people I know, I am in and out of airports regularly enough to get a pretty good feel for the way things work. It has recently become quite apparent to me how utterly useless, inconsistent, and innefectual most (if not all) airport security measures are.

On a recent trip, in accordance with recent new regulations regarding liquids, I dutifully packed my toiletries into a 1 Quart ziploc bag and headed to the airport. Going through security at my starting point proved to be no issue, other than the exceedingly long lines caused by the new rules, but coming back was a different story. You see, my toothpase was almost all used up, so I had folded the empty “tail” of the tube in order to save space and make distributing the minty-freshness onto my toothbrush easier. As I was heading through security, the TSA screener told me that if the toothpaste was more then 4 fl. oz. I could not pack it in my carry-on. My first thought was that the screener was referring to my screen/glasses cleaning solution that was also in the ziploc bag, as he had not specifically used the word “toothpaste,” but had simply gestured toward it whilst asking. In response to my “Huh?,” the TSA man informed me that if the unfolded volume (marked volume) of my toothpaste was more than 4 fl. oz., it would be considered contraband. I didn’t want to cause a fuss, and as the toothpaste was almost finished anyway, I offered to throw it away. It wasn’t until I had reached my gate that the ridiculousness of the situation actually hit me. What difference does it make how much paste the tube originally had in it; it currently has far less than 4 oz of liquid. The terrorists weren’t going to blow anything up by mixing the “essence” of what once was contained by any given container, but the absolute contents of the containers of the time the liquids were mixed. Additionally, regulations allow for the carrying of multiple 4 oz containers provided they fit into aforementioned ziplock bag. Who is to say a savvy terrorist wouldn’t simply put 4 oz of substance x into bottles labeled as containing substance y; thus allowing him to carry more than 4 oz of any given liquid.

It is possible that this incident was simply a product of the screener’s idiocy, but I fear that it is evidence of a far larger issue inherent with the system. My worry is that the regulations put in place by the TSA are not there to actually protect anybody, but simply to ease the worries of Jack and Jill American. Any reasonably intelligent person who takes the time to think about the state of security today realizes how easy it would be to sneak prohibited items onto a commercial aircraft. If the terrorists are half as smart as I am, they would have no problem executing a devastating attack on a passenger airliner. Not only that, but if I am able to think of ways to do this after a few seconds of pondering, think of what a fiercly dedicated extremist could think up in months or years of planning. This in mind, its not hard to believe that the whole fuss about airport security is a sham with two concrete objectives; to instill fear in the minds of the average air traveler, and to then ease this fear through a farce.

I understand that some assertions made in this post are fairly extreme and conspiratorial, and I don’t neccicarily hold all of them, but they none the less something to ponder and entertain yourself with the next time you fly.