Review: The greatest show on earth

Review: The greatest show on earth: The evidence for evolution, by Richard Dawkins. London: Bantam Press. 2009.


In The God delusion Richard Dawkins stated that he was not writing with the intent of converting committed theists but, rather, with the aim of influencing those who were undecided between belief and atheism. After reading The greatest show on earth, I imagine that Dawkins is likewise trying to convince the undecided rather than the hard-core creationists. On the opening page he compares the teacher of evolution to a teacher of Roman history whose class is continually disrupted by "a baying pack of ignoramuses" who vociferously assert that the Roman empire did not exist.
Some might wonder whether a less confrontational tone would be more effective in getting the reader on board. I'm not so sure. Dawkins gives the example of Wendy Wright, the president of 'Concerned Women for America', who was interviewed for the Channel Four documentary The Genius of Charles Darwin. She repeatedly questions the existence of "intermediate" fossils, whilst Dawkins repeatedly ripostes that they are in the museums if only she would care to look. When one listens to Wendy Wright and the many people like her (see some of the risible creationist videos on YouTube) one feels that they are a lost cause.
However, for anyone who is unsure about the case for evolution and is willing to actually read about the evidence, then The greatest show on earth is a brilliant exposition. Each chapter deals with a different aspect of the case and then asks how this could be explained by young earth creationism (creationists who believe that the world was created within the last 10,000 years) or intelligent design (creationism dressed up in the clothing of science).
Along the way Dawkins exposes many of the myths propounded by creationists. For example, although most evolution occurs over millions of years, some evolutionary change can be observed and, indeed, experimentally induced. In one key study, the coloration of guppies evolved to be more or less bright, depending on whether they had been placed in non-predated (or weakly-predated) pools rather than highly-predated pools. Likewise, artifical selection (e.g. dog breeding) is a de facto demonstration that animal forms can change, as opposed to all forms having been place on earth by a creator.
Another myth exposed by Dawkins is that of the "missing" link in the fossil record. Dawkins points out that evolution would be true even if we had no fossils; molecular analyses of existing species demonstrates more clearly than fossils just how different species are related to each other. But we are lucky that any fossil record has survived, and since Darwin's time many "intermediate" fossils have been found, showing the ancestral forms of many living species. Occasionally, some of the fossils in the pre-human lineage get reclassified as an earlier or a later form. However, this actually supports the evolutionary case by showing how close some of the different forms are to each other. In fact, if we had an entirely complete fossil record then it would be impossible to actually classify different forms because the changes between successive generations would be imperceptible.
Dawkins shows throughout how the creationist case has to fall back either on flat denial of the facts or on implausible forms of special pleading. A case in point is the use of radioactive clocks to determine the age of the earth's rocks. Radioactive clocks depend on the half-life of isotopes - the time taken for half the atoms to decay. Potassium-40 has a half-life of 1.26 billion years, but perhaps a creationist could argue that its half-life was different prior to Noah's flood. Special pleading, yes, but the pleading is worse when you bear in mind that other isotopes have different half-lives, so God would need to fiddle all of these in order to show that the earth was created about 6,000 years ago.
One of the most amusing arguments against creationism is that of our interior physiologies. In contrast to the impressive exteriors of all creatures, the insides are frequently a shambles. For example, in mammals the laryngeal nerve does not pass directly from the brain to the larynx but, rather, takes a detour. Most dramatically, in the giraffe the laryngeal nerve passes right down the neck and back up again, a detour of about 15 feet. The reason for this absurdity lies in the evolution that transformed fish ancestors into mammals, which involved the stretching of the neck and the development of other structures.


Throughout The greatest show on earth the writing is crystal clear. The footnotes - so often a distraction in many books - are either illuminating or amusing. Although I knew the basics of evolution, I still learned a lot from this book. Anyone else who is willing to actually be exposed to the evidence for evolution would be well advised to read it.

Derren Brown and the lottery prediction

On 9th September, Derren Brown appeared to predict the results of the UK National Lottery on Channel 4 television. Two days later, he purported to explain this in terms of the "wisdom of crowds". He referred to a study reported by Francis Galton in 1907, in which many people attempted to guess the weight of an ox at a country fair. Although many different estimates were made, the average of these was staggeringly close to the true weight. Brown claimed to have averaged the guesses of a panel of people in order to produce the lottery prediction (the explanation was also mixed up with some stuff about automatic writing and group bonding).

On the blog site of the Guardian newspaper, some people expressed their doubts about the whole wisdom of crowds concept, including the Galton study. I posted the following response (I've corrected a small error in this reprinting):

Regarding the wisdom of the crowds argument, which some people have doubted, aggregating imperfect judgments can improve accuracy but it doesn't apply to the case of lottery numbers. Let's take Galton's example of people guessing the weight of an ox, mentioned in the programme (Galton's paper was published in Nature). In reality, the ox weighed 1198 lbs. If person A guesses the weight to be 1178 lbs then s/he is inaccurate by 20 lbs. Person B guesses the weight to be 1208 lbs and is inaccurate by 10 lbs. Thus, the average level of inaccuracy is 15 lbs. But suppose we average their two guesses; this gives an estimate of 1193 lbs, which is inaccurate by only 5 lbs. Thus, the level of error obtained by averaging the estimates is less than the average error of each individual estimate.


There are a couple of things to note here. First, the two estimates in the example fell either side of the actual weight, a phenomenon called 'bracketing'. With multiple estimates, at least one instance of bracketing is necessary in order that averaging estimates will improve overall reliability. When making estimates about something where knowledge can be applied, even imperfectly, multiple estimates are likely to cluster either side of the true answer. In the case of the lottery, knowledge cannot be applied. Because numbers are randomly determined, there is nothing "real" for guesses to cluster around. Indeed, the numbers 1 and 49 cannot even be bracketed, as guesses can only fall to one side of them.


Second, even where bracketing can occur, thus leading to greater reliability of the averaged estimates, greater reliability does not mean pinpoint accuracy. Rather, it simply means a reduced level of error. In the case reported by Galton, 787 people guessed the weight of the ox and the average of their estimates fell 1 lb short of the correct weight. Thus, even if it were possible to apply the wisdom of crowds to the National Lottery, the notion that this would lead to seven correct answers is risible.


I don't know how Brown did it, but having viewed the video of the "jumping ball" I'm inclined to agree that there was something along the lines of the split screen trickery that many have suggested.


As someone who teaches the psychology of judgment, it does concern me a little that mixing up genuine science with a barrel-load of hokum could damage people's understanding of, or trust in, the former.

UK government's apology for Turing's mistreatment

The online petition (link below) for an official apology over the treatment of Alan Turing has produced the following response from Prime Minister Gordon Brown. Cutting and pasting from the original email led to a few formatting errors, which I've tried to fix, but some may remain.

Understandably, the message focuses on Turing's codebreaking work during the second world war, but many of us also celebrate his contributions to cognitive science.

DH

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Thank you for signing this petition. The Prime Minister has written a response. Please read below.

Prime Minister: 2009 has been a year of deep reflection – a chance forBritain, as a nation, to commemorate the profound debts we owe to those who came before. A unique combination of anniversaries and events have stirred in us that sense of pride and gratitude which characterise the British experience. Earlier this year I stood with Presidents Sarkozy and Obama tohonour the service and the sacrifice of the heroes who stormed the beaches of Normandy 65 years ago. And just last week, we marked the 70 years which have passed since the British government declared its willingness to takeup arms against Fascism and declared the outbreak of World War Two. So I am both pleased and proud that, thanks to a coalition of computer scientists,historians and LGBT activists, we have this year a chance to mark andcelebrate another contribution to Britain’s fight against the darkness ofdictatorship; that of code-breaker Alan Turing.

Turing was a quite brilliant mathematician, most famous for his work onbreaking the German Enigma codes. It is no exaggeration to say that,without his outstanding contribution, the history of World War Two couldwell have been very different. He truly was one of those individuals we canpoint to whose unique contribution helped to turn the tide of war. The debt of gratitude he is owed makes it all the more horrifying, therefore, thathe was treated so inhumanely. In 1952, he was convicted of ‘gross indecency’ – in effect, tried for being gay. His sentence – and he was faced with the miserable choice of this or prison - was chemicalcastration by a series of injections of female hormones. He took his own life just two years later.

Thousands of people have come together to demand justice for Alan Turing and recognition of the appalling way he was treated. While Turing was dealtwith under the law of the time and we can't put the clock back, his treatment was of course utterly unfair and I am pleased to have the chance to say how deeply sorry I and we all are for what happened to him. Alan and the many thousands of other gay men who were convicted as he was convicted under homophobic laws were treated terribly. Over the years millions more lived in fear of conviction.

I am proud that those days are gone and that in the last 12 years this government has done so much to make life fairer and more equal for our LGBTcommunity. This recognition of Alan’s status as one of Britain’s mostfamous victims of homophobia is another step towards equality and longoverdue.

But even more than that, Alan deserves recognition for his contribution to humankind. For those of us born after 1945, into a Europe which is united,democratic and at peace, it is hard to imagine that our continent was once the theatre of mankind’s darkest hour. It is difficult to believe that in living memory, people could become so consumed by hate – by anti-Semitism, by homophobia, by xenophobia and other murderous prejudices– that the gas chambers and crematoria became a piece of the European landscape as surely as the galleries and universities and concert halls which had marked out the European civilisation for hundreds of years. It is thanks to men and women who were totally committed to fighting fascism,people like Alan Turing, that the horrors of the Holocaust and of total warare part of Europe’s history and not Europe’s present.

So on behalf of the British government, and all those who live freely thanks to Alan’s work I am very proud to say: we’re sorry, you deserved so much better.

Gordon Brown

If you would like to help preserve Alan Turing's memory for futuregenerations, please donate here: http://www.bletchleypark.org.uk/

Petition information - http://petitions.number10.gov.uk/turing/

Attending to dual-screen presentations

Large classrooms now often have not one, but two, screens onto which slide shows are presented. The idea (presumably) is that people on the left hand side of the room will find it easier to look at the left hand screen and those on the right will look at the right hand screen. But before implementing this design, did anyone do any research into how audience and speakers will actually behave?

Whilst at a conference yesterday, I noticed that the speaker spent the whole time standing to the left of the left-hand screen (as viewed by the audience). Every now and again I glanced at the audience, the vast majority of whom were also looking at the left hand screen. Even those in the front-most rows on the right were mainly looking at the left-hand screen. I myself found it very difficult to watch the screen on the right whilst listening to a speaker on the far left of the room. Perhaps this is because every now and again you want to switch attention from screen to speaker and vice versa, and this is easier if you are looking at the screen closest to the speaker.

More than this, however, the head and hand movements of the speaker him/herself are also a guide for the audience. When the speaker shifts his/her gaze from the audience to the screen, or waves a hand towards something on the screen, this is a cue for the audience to direct their own attention to the same thing. And if the speaker is using a laser pointer, that of course will only be pointed at one screen.

I began to wonder whether the learning experience may actually be slightly harder for the audience on the far side of the room from the speaker. Could the screen in front of you be a distraction? You glance at it occasionally, but then it feels uncomfortable so you switch your attention to the other screen or the speaker? This may be an idle worry, but has anyone researched this?

Obviously, the way the speaker positions him/herself may matter. What happens if the speaker stands in the centre of the room, between the two screens? In a different talk yesterday, I noticed that a centrally-positioned speaker still seemed to only look at the screen to his right (the audience's left), and consequently this was where the audience mostly looked. However, this may have been partly determined by the positioning of the computer screen on the desk in front of the speaker. From the speaker's viewpoint, this was positioned to the right of the desk and also with a tilt such that the speaker would have naturally looked rightwards to see the computer screen.

If the majority of an audience only look at one of the two screens, then surely having two is actually a waste of money. This is even worse if the non-focal screen is actually a distraction. However, I don't know of any research and would be interested to know if there is any.