Live from Austin!

The Science Museum of Minnesota plans to shut down during the Republican National Convention next year so it can host convention events.

Presumably they’ll cover up the scary exhibits with drop cloths.

A study of the brains of political partisans shed some scientific light on the obvious, and will be worth remembering in this upcoming year:

The Democrats and Republicans were given a reasoning task in which they had to evaluate threatening information about their own candidate. During the task, the subjects underwent fMRI to see what parts of their brain were active. What the researchers found was striking.

"We did not see any increased activation of the parts of the brain normally engaged during reasoning," says Drew Westen, director of clinical psychology at Emory who led the study.

Yeah, no shit.

Once partisans had come to completely biased conclusions — essentially finding ways to ignore information that could not be rationally discounted — not only did circuits that mediate negative emotions like sadness and disgust turn off, but subjects got a blast of activation in circuits involved in reward — similar to what addicts receive when they get their fix, Westen explains.

"None of the circuits involved in conscious reasoning were particularly engaged," says Westen. "Essentially, it appears as if partisans twirl the cognitive kaleidoscope until they get the conclusions they want, and then they get massively reinforced for it, with the elimination of negative emotional states and activation of positive ones."

In other words, Washington was right.

From a neat blog posting summarizing some research on sex and intelligence:

By the age of 19, 80% of US males and 75% of women have lost their virginity, and 87% of college students have had sex. But this number appears to be much lower at elite (i.e. more intelligent) colleges. According to the article, only 56% of Princeton undergraduates have had intercourse. At Harvard 59% of the undergraduates are non-virgins, and at MIT, only a slight majority, 51%, have had intercourse. Further, only 65% of MIT graduate students have had sex.

The bar chart of results from a Wellesley college survey is amusing, with the percentage of students who are virgins ranging from 0% for the Art students, up to 83% for the Mathematics students.

The only mystery is why the figure for Computer Science students is only half that for Mathematics. My guess is that it’s because Wellesley is a female-only college, and female computer scientists can basically get on the Internet and find any number of desperate male computer scientists to hook up with.

Also:

…another revealing finding from the Counterpoint survey was that while 95% of US men and 70% of women masturbate, this number is only 68% of men and 20% of women at MIT!

So the hypothesis is that smarter people have a lower sex drive. Obviously there are going to be exceptions, however.

Psychology Today has an article listing and explaining 10 scientific truths about human nature that people just don’t want to admit.

Like the fact that most suicide bombers are Muslim, and that humans are naturally polygamous. Or that behavior many women interpret as “hostile” or “harrassing” is actually men treating women as equals.

Some people believe that they perceive the world as it actually is. There are many experiments that can disprove this notion. For instance, take a look at Edward H Adelson’s checker shadow illusion. To me, the two squares A and B look so obviously different that if I didn’t know it was an optical illusion, I would never pause to think that they might be exactly the same color.

Similar experiments can demonstrate that your hearing is just as subjective. There are tone mixes that can be played that some people will hear as ascending tones, some as descending tones. The sense of touch can be fooled too. I’ve not heard of any demonstrations of the subjectiveness of smell-based perception, but I don’t doubt that it could be done.

Nevertheless, we like to think that we see things as they are. Sure, maybe the colors aren’t always right, or the angles look distorted, but the basic details are correct, or so we assume. You were probably taught, like me, that the eye works like a camera—the scene before it is focused by the lens onto the retina, and the signals from the rods and cones are transmitted to the brain where they are processed into an image, right?

Wrong, it turns out.

In April’s Scientific American magazine there was a fascinating article that described how the eye actually works. Further details from the same researchers were published in Nature.

It turns out that the rod and cone cells connect to 10 different kinds of neurons known as bipolar cells. The bipolar cells have long axons which extend into one of 10-12 different layers of what’s known as the plexiform layer. Also connecting into those layers are 12 different types of ganglion cells, which are the cells that actually transmit to the optic nerve. There are also at least 27 types of amacrine cells, which can affect signal transmission between the layers and change propagation of signals within a layer.

Basically, the eye isn’t at all like a camera. It’s more like a chunk of brain tissue that has been wrapped around the inside of the eyeball. (Stranger still, all the sensor cells are on the outside, and all the wiring is on the inside, so light has to pass through everything else to get to the sensors. Intelligent design? I don’t think so.)

Anyway, the sensory data from the rod and cone cells is processed by this retinal tissue into 12 separate streams of information, all of which are sent to the brain in parallel.

One signal stream consists of only the edges detected in the scene; another is only the moving edges. One has just the shadows. One detects and emphasizes highlights. One seems to notice changes of brightness with respect to time. One detects large uniform areas. Another seems to detect backgrounds around central figures. And so on.

The 12 streams of data are sent to different parts of the brain. The brain then somehow uses all of these special purpose signals to work out a mental model of the external world, which it uses to “color in” the photo-like perception we imagine we have.

This is, of course, why optical illusions work. Given the nature of the signals sent to the brain, the bigger mystery is how the brain mostly does such a good job of fooling us into thinking we have cameras for eyes.

A recent BBC Panorama documentary has suggested that wifi Internet might be a major health hazard. Scary quotes about chromosome damage and radiation exposure have appeared all over the Internet.

Unfortunately, the documentary’s conclusions are junk science.

Let’s start off by noting the inverse square law, a piece of basic physics which applies to electromagnetic radiation exposure. Basically, the strength of a signal varies in proportion to the distance squared.

The people who put together the documentary measured the wi-fi signal at a distance of 1m, and the cell phone tower signal at a distance of 100m. From their measurements, they concluded that the wifi signal was “three times the highest level of the mast”.

Well, no, it wasn’t. Because the cellphone signal was measured 100x further away, it was attenuated by a factor of 100×100 = 10,000×. So an accurate quote would be that the wi-fi signal was “three times the level of the cell phone mast divided by 10,000″. Not as exciting, though, is it?

You might argue that it’s reasonable to measure at different distances because people don’t tend to sit close to cell phone masts, but they do tend to sit close to wi-fi equipment. However, think for a moment about how a cell phone works. Yes, the mast transmits a signal to your phone, which is 10,000× weaker by the time it gets to you. However, you don’t just listen to your phone; hence, it must also transmit your voice back to the network. And the same physics works the other way: the signal your phone transmits is 10,000× weaker by the time it gets back to the mast.

So as you might guess, the radiation your phone emits is much, much more powerful than the radiation that reaches you from any nearby mast. That’s the radiation levels the BBC program should have been measuring and comparing with wi-fi.

While raw power is measured in watts, the relevant measurement for assessing radiation danger levels is the Specific Absorption Rate or SAR, which is measured in watts per kilogram. An adult’s body has much more bulk to dissipate the electromagnetic field, hence it’s less susceptible than (say) a lab rat’s body.

The US limit on radiation from consumer mobile phones is 1.6W/kg. (That’s lower than the European limit, so we’ll take that as our guideline.) The limit for devices like wifi is a mere 0.08W/kg. (Figures are in FCC OET Bulletin 56.)

Those are the maximums. The actual SAR ratings of common mobile phones are well documented. A value of 0.9 is fairly normal, with few phones below 0.5. So already, it’s clear that the average mobile phone actually exposing you to 0.9W/kg is likely far more dangerous than the 0.08 W/kg theoretical maximum allowed for devices like wi-fi.

Let’s look at some actual figures for wi-fi output compared to phones. I haven’t managed to find SAR ratings for wi-fi (if you have any, let me know), so we’ll have to compare power output in both cases. Peak power output from a phone is around 2W, with the average being around 250mW, according to a handy page from the Australian Radiation Protection and Nuclear Safety Agency.

Coincidentally, 250mW is the absolute maximum power output you can get from my wi-fi router (a Linksys WRT54GS). But to get that, you have to hack the firmware. The default power output for the router is around 20mW, 100× less than the phone. Now add in the fact that mobile phones are held against your head, whereas your wifi antenna is likely at least 30cm away from you at all times, and invoke the inverse square law again. The end result is that the electromagnetic radiation you get from wifi is a tiny fraction of that which you get from mobile phones.

As a UK Health Protection Agency scientist puts it in The Times, “a year sitting in a classroom near a wireless network is roughly equivalent to 20 minutes on a mobile.”

Aha, you say—what if you don’t use the mobile phone much? I’m afraid you still get irradiated. As you travel around, the signal from the nearest cell will get weaker. The phone checks signal strength every 7 seconds. If it drops off too far, the phone sends out an “I’m here!” transmission in order to locate another cell.

Given that each cell covers a square km or two, or as little as a few blocks in cities, taking a quick drive across town can involve your phone transmitting dozens of times. So wi-fi is a pretty negligible concern compared to carrying a mobile phone, let alone using one.

Wi-fi and phones aren’t the only sources of electromagnetic radiation, though. Wi-fi operates at 2.4GHz, which just happens to be the same frequency as your microwave oven. In fact, you may have noticed that your wi-fi signal strength is lower if you’re cooking something in the microwave, especially if your laptop is in the kitchen.

You might wonder why wi-fi operates at the same frequency as microwave ovens. Well, microwave ovens operate at 2.4GHz because that’s the frequency that’s best for heating up water molecules. For the same reason, it’s a bad frequency for long distance telecommunications through damp air, so it hadn’t been grabbed for any major commercial purpose. Hence, it was declared as free unlicensed spectrum for local low-power radio. This lack of regulatory hurdles led to innovation such as cordless phones, wireless video surveillance systems, and (eventually) wi-fi.

This also means that the effect of microwave exposure at wi-fi frequencies is simply heat. It’s not like nuclear radiation, it doesn’t mutate your genetic material; it simply warms up your water molecules a bit. From a scientific perspective, people are having a hard time coming up with theories to explain why localized warming of the body might cause damage. (In fact, it’s reported anecdotally that sailors on night watch on deck during WW II would stand in front of the radar in order to keep warm. They got hundreds of times the electromagnetic radiation warming you could ever get from a phone, yet they apparently didn’t suffer major damage.)

But let’s head back to the kitchen. Microwave ovens are allowed to leak up to 5mW/cm² at 5cm distance. A leaky oven may expose you to 0.256W/kg, at the same 5cm distance, according to measurements of leaky microwave ovens from the Australian Radiation Protection Agency. So at typical watching-lunch-rotate distance, it’s about the same level of danger as the radiation from your wifi router. So if you’re worried about wi-fi, you should be worried about your microwave oven too.

But there’s a much larger source of microwave radiation in your life. It’s called the sun. Summer sunlight at ground level can be up to 100mW/cm² of electromagnetic radiation. So standing outside on a sunny day irradiates you with 20× the radiation of a leaky microwave or wifi router, and a good chunk of it is microwave frequency.

So if you’re worried about electromagnetic radiation, perhaps the rational thing to do is what us computer scientists do—stay inside and browse the Internet via wi-fi, but never emerge blinking into the daylight…

Meanwhile, there are a growing number of people who believe that they are sensitive to low levels of microwave radiation like that found in wi-fi and sunlight. They call the phenomenon “electrosensitivity”. They claim that wi-fi and mobile phones give them headaches, make them nauseous, and so on, after just a few minutes. So, what’s the evidence?

Well, so far there have been at least 7 separate scientific trials in which allegedly electrosensitive people were asked to tell researches whether a mobile phone signal was present. In proper double-blind trials, “electrosensitive” people were unable to detect a mobile phone signal even after 50 minutes of continuous exposure. (Update: Here’s a very recent one.)

And even if they could have detected the signal—which they couldn’t—that wouldn’t have proved that the signal was responsible for their reported symptoms.

So if you believe wi-fi or mobile phones are making you ill, please do see a doctor—specifically, a psychiatrist. You may have a psychosomatic illness, you may be schizophrenic and believe you are picking up radio waves with your teeth, but you are not being made sick by people’s wireless Internet. If you truly believe you can tell when a mobile phone or wi-fi system is transmitting, sign up for a research study and prove it. You’ll be the first.

The sad thing is, though, that there are crackpots in even the highest levels of government. So expect to see more scare stories about wi-fi in the next few years.

I’m old enough to remember that back in the 80s, the scare story was about overhead power lines. They were making us nauseous, giving us cancer and leukemia, causing headaches. Funny how that risk seemed to vanish.

Microwave popcorn uses an artificial butter flavoring called diacetyl.

Numerous studies have now linked diacetyl fume inhalation to a rare condition called bronchiolitis obliterans, in which the bronchioles of the lungs get blocked by masses of fibrous tissue.

The problem has been known about since 1999, but so far federal agencies haven’t done anything. There’s now a bill in California proposing to ban diacetyl by 2010.

The Delve Special episode “Food for Thought” just seems more and more relevant as the years go by.  Random quote: “Everyone has to die of something, so it might as well be something delicious.”

Scientific American, February:

Money is an incentive to work hard, but it also promotes selfish behavior. Those conclusions may not be surprising, but psychologists at the University of Minnesota recently found that merely thinking of money makes people less likely to give help to others.

The researchers got people to think about money by showing them words related to money, having them handle play money, or revealing a poster with pictures of money on it. They then got the subjects to perform tasks which had nothing to do with money, but assessed social behavior. The result: people who think about money are less helpful and also less likely to seek help from others.

Science, November 17. [Link]

The American Psychological Association (APA) set up a task force to “examine and summarize the best psychological theory, research, and clinical experience addressing the sexualization of girls via media and other cultural messages”.

The report has now been published.

However, I note that there were no men on the task force, and apparently no men were invited to comment (according to the document). It seems statistically unlikely to me that all the experts in the field of media effects on children are female. If a task force made up entirely of men produced a report on (say) the effect of violent media on teenage boys, and took no comments from women, I suspect that the report’s credibility would be questioned. Will this report get the same reaction?

A (Reagan-loving) social work master’s student at Southern Connecticut State University ran a study encouraging psychiatric outpatients to vote.

When he went back and analyzed his data, he discovered that there’s a direct statistical correlation between how psychotic a person is, and how likely they are to vote for George W Bush.

In the interests of balance I should say that the reverse inference has yet to be demonstrated statistically, and is merely anecdotally true.