Nine Months’ Weight (pun included, no extra cost)

I have it on good authority that I was a very large baby. Documents to this effect, signed and certified by a legitimate medical practitioner, are currently on file at the family residence and can be viewed by all interested parties for an eminently reasonable $10 entrance fee.

If we’re being intimate (and for God’s sake let’s) then I don’t mind admitting that I tipped in the scales at a respectable 4.5kg. For a large proportion of my anglophone audience, this corresponds to slightly under 10 pounds. For devotees of more abstruse units of measurement, this equates to 159 ounces, seven-tenths of a stone, or 22,500 carats. To put it in context, a top female athlete can Put a Shot of this sort of weight around about the length of a tennis court.

And despite that added bulk slowing me down on the way out of the starting blocks, I seem to have raced through 22 years while remaining in a fortunately very good state of health. But how of much that has been luck? And how much of a handicap could those extra ounces (or pounds – or, indeed, kilograms) actually have been? Might the possession of this excess avoirdupois strangely, counterintuitively, paradoxically even, have been responsible for this as-yet unbroken run of good health?

This was among the complex and controversial issues that this week’s episode of Horizon was due to tackle. To what extent does the time spent in the womb influence the development of the emergent human being? The programme’s title seemed to give part of the game away: “The Nine Months that Made Us” was surely going to come down quite firmly on the side of Nature in this round of the Nature-Nurture slugging match. And yet something odd happened. Or more precisely, didn’t. After having laid its stall open at the carnival of ideas and rung the bell to get customers to gather, I found that the salesman himself had very little to sell.

By which, I should stress, I don’t mean that the programme was devoid of content. On a biological, factual level, my physicist’s mind was able to retain the following pieces of information:

1. Larger weight at birth has been shown to correspond to a lower risk of suffering from diabetes.
2. Placentas of the same size can, in different mothers, contain foetuses of substantially different weights.
3. India and Saudi Arabia are fantastic filming locations.

That last point may seem a little unfair, so I feel it only right to qualify my meaning. As always when watching pieces of science communication, one has to try and separate the Science from the Communication – the Story. And this third episode of the current season of Horizon shed light on what I thought was a very interesting story; sadly, one which had very little to do with the programme’s content.

What “The Nine Months that Made Us” principally showed was the way in which global science can bring individuals together. The way in which a scientist based in Portsmouth can collaborate with a field worker in India or a doctor in Saudi Arabia to verify or negate his claims. The Portsmouthian doctor in question was Dr. David Barker, the researcher who first aired the contentious view that birth weight can shed light on future development. Hovering in the background of most shots like a benevolent Alfred Hitchcock, Dr. Barker and his theories were unquestionably the linchpins on which the episode was hung.

Around about twenty years ago, the Doctor came up with a theory. It corresponded at the time to data found in Hertfordshire birth records, but any statistically meaningful conclusion necessitated a much wider pool of data. Cut to India, where a local diabetes specialist notices the remarkably high predisposition of his (apparently) healthy patients to develop diabetes. Having come across Barker’s seemingly simplistic model, he is intrigued. And so for the next 21 years, a study is carried out on a batch of new-born babies as they mature, to see how their weight at birth might be related to their chances of becoming diabetic.

Here we see the giant of Science in full stride. To paraphrase Albert Michelson on the occasion of his Nobel lecture, the two legs of science are Theory and Practice. First, one must move forward. Then the other, slowly, must take the next stride and find a stable footing. Only in this way is it possible for the giant to progress.

The Myth

In the naive days of our (hopefully corpulent) youth, some of us are told about the wonderful example of Experiment-Theory-Experiment immortalised in the story of General Relativity. The aforementioned Albert Michelson and his colleague Edward Morley, the narrative goes, were looking to measure the speed of light. At the time, it was believed that permeating the Universe was an insubstantial, transparent gloop pompously known as the luminiferous aether. Consequently, our two heroes maintained, the speed of light as measured on Earth would be the sum of the speed of light in a vacuum added to the speed of our planet relative to the aether.

In an experimental set-up known to high school physics students around the world, they tried to measure the speed of light at different points on the Earth’s orbit around the Sun, thereby hopefully accounting for the Earth’s contribution to the speed of light.This has become known as the most famous null experiment in history, because what it revealed was that the speed relative to this so-called aether didn’t make the blindest bit of difference. Light travelled at the same speed in all directions – this aether stuff might as well not exist.

And so when Albert Einstein came along a few decades later and proposed that “the speed of light is a universal constant”, his theory finally allowed the giant to lift his Theory leg off the floor. Then, our story continues, Einstein’s theory of relativity made a number of experimental predictions which could then be tested – such as the way in which rays of light are supposed to bend around particularly massive objects. This allowed the English astronomer Eddington to send an expedition to the islands of Sao Tome and Principe during a solar eclipse in 1919 and verify Einstein’s predictions. Act III of our little fablieau? Einstein is proven to be right, and so the giant’s Experiment leg crashes triumphantly to the floor.

The Reality

In their classic book “The Golem”, to plug another item on my course’s reading list, Harry Collins and Trevor Pinch strap this story into the dentist’s chair and call Larry Olivier in with the drills. In other words, they dare to poke holes in this wonderful platonic ideal we are all taught to idolise and show us the messy world of human interactions writhing beneath the surface.

For instance, it turns out that Michelson and Morley’s 1887 experiment was not conducted thoroughly enough for its null result to be conclusive. Not only that, but less than a decade later Michelson had conducted another experiment whose findings indicated that the aether did in fact exist. Einstein’s Theory of Relativity did not emerge into a world expecting it to come along. Even more shockingly, it seems that the reason Eddington’s measurements matched Einstein’s predictions so accurately was that he considered all deviating results to be the result of experimental error. Ergo, any data points left were self-selected and consequently made the validation of Relativity meaningless.

The Conclusion

But surely, I hear you cry, this is bad science! This is not the way it is supposed to be done! On paper, absolutely right. But in practice, this is neglecting the all-important human elements of intuition and practicality. Eddington demonstrated remarkable scientific insight in correctly identifying erroneous data points – it just so happens that his name would be less respected today were he to have eliminated the wrong ones from his results. The Two Legs of Science is the way we teach the scientific method, and this is the ideal to which science and scientists alike must always hope to cling. We don’t always do it right, but that shouldn’t stop us trying.

The momentary snapshot of the eternal give-and-take that exists between theorists and experimentalists was to my mind by far the only interesting story in this week’s episode – a story of which we got tantalising glimpses among a lot of needless repetition and bland, nonspecific overgeneralisations. I hope next week’s episode strikes a better balance.

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