Mind maps
Creating an accurate map of the brain’s connections is certainly a monumental undertaking (5 February, p 32) and Douglas Fox rightly compares it to the early days of genome research. Like the sequencing of the human genome, which was long believed to be impossible, mapping the entire human brain will be greatly aided by advances in technology.
There is, however, another parallel between these two fields. While obtaining the complete sequence of the human genome undoubtedly represented a major milestone in biomedical research, it could not explain the full complexity of how we develop, age or become ill. Only now are we beginning to understand the many roles our genes play.
The same is likely to happen with the connections of the brain. The mere presence of a synapse between neurons is only part of what is needed to understand how these cells communicate with each other. There are many factors that influence the role a synapse plays in a neural network, all of them difficult, if not impossible to deduce from microscopy images.
These limitations should not deflect attention from the potential benefits of a brain-mapping project, such as insights into how our mind works, or possible treatments for neurological disorders.
I want to be like you
In spite of the impressive achievements of artificial intelligence in controlled environments, no mathematical technique of information processing will ever produce an “intelligent” robot able to perceive implicit possibilities in a non-controlled environment (29 January, p 28).
The reason is simple. We store concepts and memories of objects not as combinations of logical properties, but as patterns of interaction with our environment. For instance, when lacking a hammer, we will almost instantly and without extensive analysis look for a heavy, solid object to use instead.
All objects are stored mentally as hierarchies of interactive properties, progressing from the general to the more specific. In order to perceive things in the way we do, we have to gradually collect increasingly specialised interactive experiences over a long period of time. This is how children learn to handle objects, and it would be the way in which we could create robots capable of thinking like us, too.
The game's afoot
The gushing praise in your publication and elsewhere for IBM’s Watson supercomputer seems to me unwarranted (19 February, p 6). Watson did indeed win the Jeopardy! matches, but I became suspicious while watching them as I could answer a sizeable percentage of the questions, and I am sure the two human competitors could have answered far more. So why did Watson dominate?
Simple: contestants have to wait until the question is completely read out and a light has come on before they can press their buzzer. The contestant who signals first gets to answer. It turns out that Watson is faster than a human at this; the two human contestants never had a chance to answer a question that Watson had decided to answer. In fact, Ken Jennings was visibly frustrated time and again while pressing his buzzer, as he obviously knew the answers.
A fair contest would pit the two human champions against Watson in a match that would eliminate the computer’s mechanical advantage. Otherwise, the only insight we will glean from these Jeopardy! competitions is that computers are faster than the human nervous system in responding to a stimulus. Big deal.
Stellar seed
I was horrified by the proposition that we should send life to other planets (5 February, p 40). Why anyone should seriously favour contaminating ecosystems on other planets with terrestrial bacteria I find hard to understand.
Let’s not forget that it is likely that such ecosystems do exist. Organic compounds are common even on meteorites and comets, so life is likely to arise on a planet if it is even remotely Earth-like.
Admittedly, one unusual feature of our planet is its oversized moon. The tides it creates were probably instrumental in getting life out of the oceans and onto land. One may expect, therefore, that life elsewhere may be confined to water.
This has an ironic corollary. Aquatic life, however intelligent, would have little use for radio waves, making it likely that most of our attempts at interstellar communication are misdirected.
From Leo Passaportis
I was surprised that your feature about sending life to other planets did not mention the debate surrounding the Russian Federal Space Agency’s Phobos Sample Return Mission. This aims to send live bacteria into the solar system for the first time, apparently in violation of the UN Outer Space Treaty of 1967.
As Barry DiGregorio argues in an earlier New 杏吧原创 article (25 December 2010, p 32), our knowledge about the “survivability” of life on another planet is “constantly changing with each spacecraft mission”. So why embark on such projects now, just because the technology allows?
Our endeavours to study extrasolar planets are just starting to bear fruit. There may come a time for philanthropically sharing terrestrial life forms with these other worlds, but it is not yet.
Plymouth, Devon, UK
Paint it yellow
I found it strange that your article about the darkening of some of van Gogh’s yellows suggested that the cause of chrome-based paints darkening over time was unknown (19 February, p 5).
Having worked with a major manufacturer of chrome pigments for 20 years, I can tell you that the overwhelming cause is exposure to atmospheric sulphide gases. Over time, exposure causes the lead chromate present in the pigment to be converted into lead sulphide, which is black.
Van Gogh’s paintings must have had many years of exposure to a polluted atmosphere 鈥� they certainly started their life long before clean air acts!
Hair today鈥�
While reading Roger Highfield’s article “Days of wonder” about the strange science of everyday life (19 February, p 34), I was particularly interested in our apparent inability to recognise even very obvious changes which happen right before our eyes.
After having had a beard for 27 years, I shaved it off. People who had known me for years didn’t notice it had gone, but my colleagues, who I had known for just one year, noticed immediately. In fact, many of my co-workers said I looked better without the beard, while the people who had known me longer said I looked a mess 鈥� when they finally noticed it had gone.
On another occasion, a colleague who usually sported a beard shaved it off, leaving a moustache. On first seeing him after the change, his boss said: “I see you’ve grown a moustache, Ralph.”
It was then that I realised we often don’t see with our eyes but with our brain, and it is not always accurate.
Lucky red shirt?
In the interests of experimental repeatability I decided to test the idea that women find men wearing red more attractive than those wearing other colours, as mentioned in Helen Thomson’s article (12 February, p 36).
I bought myself a plain red shirt and went to the local bar on a Saturday night. Despite remaining there for 2 hours, not a single woman indicated any interest in me. The only woman who even spoke to me was the barmaid from whom I ordered a drink. This suggests that red shirts are not attractive to women.
To be fair, other factors may have been at work. Firstly, the ratio of men to women in the bar was 16 to 1, including the two barmaids. Next, I am single, and your article mentioned that single men are less attractive to women, so this may have added to the lack of interest.
Finally, I was alone. The article also said that a man’s attractiveness is enhanced by attention from other women, so my going solo surely didn’t help my chances.
Although this evidence does not disprove the theory that red shirts are attractive to women, it does contribute evidence against the hypothesis. I intend to repeat the experiment again, albeit infrequently.
Burger bite
There is a small error in your editorial “The legacy of BSE” (29 January, p 3). You state that “in one infamous spectacle, TV viewers watched the agriculture minister John Gummer ostentatiously feeding a beefburger to his young daughter to reassure an increasingly uneasy and sceptical public”.
In fact, what TV viewers saw was John Gummer attempting to feed his daughter a burger. The child, who seemed to know and understand the issues as well as the general public, refused to eat it. This wasn’t perhaps quite the reassurance the minister intended.
Have your pi and eat it
The question of whether you prefer the circle constant pi or tau is essentially the same as whether you prefer radius or diameter (8 January, p 23).
Mathematicians tend to prefer radius, as it makes for neat equations and can be used for setting their compasses. Engineers, on the other hand, prefer diameter, as it is far easier to measure using, say, a micrometer.
Use whichever you like according to context. There is no better or worse.
For the record
鈥� We incorrectly stated that the bellbird has become extinct on New Zealand’s North Island (12 February, p 18). It has actually become locally extinct in the north of the North Island, but can still be found in the south of the island.
鈥� Lagrange points actually lie 60 degrees ahead and behind a body orbiting a much more massive one, not 120 degrees as we suggested (26 February, p 7).
鈥� In our article on the science of everyday life we underestimated the difference in the rate at which your head ages per day compared to your feet due to the effects of general relativity (19 February, p 34). It should have been 10-11 seconds per day, not 10-12.
鈥� Neptune was not discovered by Johann Gottfried Galle in 1830 as we suggested (12 February, p 48). He actually saw it for the first time on 23 September 1846.