Conditioning is a fact-of-life for scientists just as it is for non-scientists. Scientists are conditioned, through decades of education and training, to see things in a certain way. And when you see things in a certain way, it’s hard to see things differently.
One example of this phenomenon is the discovery of Uranus, which I discussed in detail in Genesis and Genes. Briefly, after Uranus was discovered and identified as a planet – the first new planet since antiquity – it was realised that it had actually been seen twenty times before but always misidentified as a star. Astronomers were conditioned to believe that there are five planets, so they couldn’t see a sixth planet. It took an outsider – the amateur William Herschel – to see something radically different.
This is an example of what the physicist John Polkinghorne calls “wearing theoretical spectacles behind the eyes”. When you expect to see five planets, five planets is what you will see, most likely. As two distinguished philosophers of science put it, “In a sense, the old saying ‘seeing is believing’ should be supplemented by another, ‘believing is seeing.’” [Physics, the Human Adventure, Gerald Holton and Stephen G. Brush, Rutgers University Press, 2005, page 282]. Scientists analyse data through lenses called paradigms, and these lenses can sometimes distort scientists’ vision.
A related concept is that of groupthink. When everyone in your group maintains a certain opinion, it is difficult to entertain a radically different position. As I wrote in Genesis and Genes:
The Canadian astronomer Donald Fernie would acerbically emphasise this psychological weak spot: “The definitive study of the herd instincts of astronomers has yet to be written, but there are times when we resemble nothing so much as a herd of antelope, heads down in tight formation, thundering with firm determination in a particular direction across the plain. At a given signal from the leader we whirl about, and, with equally firm determination, thunder off in a quite different direction, still in tight parallel formation.”
In this post, I would like to address another example of the failure to see what is there for everyone to see. A reader sent me a link to a Radiolab episode on Leonard Hayflick. Hayflick is a very distinguished scientist, having won numerous awards and prizes. He is best known for the Hayflick Limit, which is the number of times that a cell can divide before it loses the ability to divide and dies. This limit varies between different organisms. For humans, the Hayflick Limit is close to 50. In other words, human cells are able to divide about 50 times in vitro before they lose the ability to divide and die. Before Hayflick’s breakthrough, it was universally believed that cells can divide ad infinitum. That paradigm was established by Alexis Carrel (1873-1944), a Nobel Prize-winning biologist, and held sway for about sixty years.
Hayflick made his breakthrough as a young man. In the Radiolab interview, he reminisces about how he noticed that in his Petri dishes, human cells would divide for about 9 months, after which they would die. Two thoughts occurred to him. Firstly, this could not be an accident, because accidents are random, whereas in his laboratory, it was always the oldest cells that were dying – after roughly nine months in the Petri dish. His second thought was that this had to be an accident because “I had been taught, by experts, that cells are immortal. They will grow forever.” [In the Preface to Genesis and Genes, Rabbi Dovid Gottlieb quotes Yale Finance Professor Robert J. Shiller. In his book Irrational Exuberance, Shiller writes that “[People] have learned that when experts tell them something is all right, it probably is, even if it does not seem so.”]
Hayflick wanted to find out whether cells were dying in other laboratories, so he went to a lecture by one of the greatest biologists of the age, Theodore Puck (1916-2005). At the end of the lecture, he plucked up enough courage to ask the senior scientist, “Have you ever found that the cells you cultured stopped dividing?” The answer was, “Of course cells stop dividing occasionally, but when it happens I go back to the freezer and get another sample.” Cell death was happening in every biology laboratory, but was always put down to mistakes by technicians. After all, everyone knew that individual cells can divide indefinitely. As Hayflick says, “Even the brilliant Ted Puck had seen it but, like everyone else, he just hadn’t recognised it.”
Interviewer: I imagine that in a lot of labs all over the country, there must have been moments when cells stopped dividing, and at every such moment the thought that popped into the technician’s mind was, “I messed up”.
Interviewer: That seems like a crazy kind of mass delusion!
Hayflick: It’s called dogma.
What was Hayflick’s breakthrough? He simply saw something that everyone else had been seeing for sixty years but kept on misinterpreting, because of “dogma”.
Informed consumers of science must realise that scientists do not work in a vacuum. They view the results of their experiments through “theoretical spectacles behind the eyes”. There can be periods lasting decades or centuries in which the evidence that contradicts the reigning paradigm is there for everyone to see, but is ignored because of adherence to that paradigm.
Retrieved 26th January 2013.