Science is built upon what has gone before.
Scientists publish their findings to make them known. Increasingly, how they do this is changing – some claim that the days of the traditional scientific journal, of traditional peer review, are numbered. Even if this turns out to be true at some point in the future, it is highly unlikely that Newton’s famous claim of only being able to see further because he had stood on the shoulders of giants will ever cease to be true for scientists in general.
The body of experience and knowledge about the world is both immense and growing in size and complexity: we will be referencing other’s work and ideas for as long as science as a discipline exists. Science is not just “observation–hypothesis–test”; rather, our observations have to be placed within the context of what is already known – built on the foundation of the literature.
Rather distressingly then, it has come to the attention of this author that there are swathes of literature where referencing of existing work does not take place. While background is often given, the provenance of such is not clear. There is no rationale for an experiment or observation, and perhaps of even more concern, experimental data are presented without the benefit of supporting material (such as experimental set-ups, statistical analysis, etc.).
It is this author’s intention, perhaps in a number of posts in this column, to highlight some of the more egregious examples of this practice. It is my desire to warn others of the ill-seated foundations of much research, and perhaps persuade the original authors to revisit their work and set it within the correct context, and, where necessary, repeat experiments.
Today I wish to re-examine the classic paper, “I’ll never fall in love again” (Bacharach B and David H. Promises, Promises. 1968).
The primary claim in this paper comes early on, and it is worth quoting in full:
“What do you get when you kiss a girl?
You get enough germs to catch pneumonia”
On the face of it, this seems true enough. A recent study found that an “intimate kiss” (Kort R et al. Microbiome. 2014) of 10 seconds could transfer 8x107 bacteria. This certainly seems sufficient to cause pneumonia, but the authors of that study were not concerned with the medical implications of such microbial exchange. However, as shown by Shrestha and co-workers, in a virus-challenged individual as few as 105 bacteria can result in infection (Shrestha S et al. J R Soc Interface. 2013). On the other hand, a “quick smooch” might only result in the transfer of 103 bacteria – two orders of magnitude less than that required for a successful infection.
Pneumonia is not only caused by bacteria: viruses, fungi and other parasites and pathogens can also be responsible. It is not clear to what extent these agents are transferred by kissing.
The second part of this claim is also memorable:
“After you do, he’ll never phone ya”
A PubMed search for “kiss” and “phone” yielded only two papers: one in which “Kiss” is the surname of an author, and a second concerning post-decompression venous gas emboli in divers, where KISS is used as an acronym for Kisman Integrated Severity Score.
Bacharach and David present no data in support of their claim. While the author is aware of anecdotal reports, it should not be beyond the ken of such respected researchers to design an interventional study examining the actions of men in respect of telephony behaviour following a kiss (whether “intimate” or “quick smooch”). One might suggest that text messaging and peer-to-peer internet protocols should also be included in the trial design.
There are other claims in the report that are questionable, but perhaps the most serious comes, ironically enough, in a corrigendum to the original (Carpenter KA et al. Close to You. 1970).
“What do you get when you fall in love?
You get enough tears to fill an ocean”
This is a breathtaking claim, and I was unable to find any evidence whatsoever to support it. However, a simple calculation will serve to demonstrate the fullness of its fallacy.
The National Geophysical Data Center (Boulder, Colorado, USA) estimates that the Atlantic Ocean has a volume of 310,410,900 cubic kilometres (3x1020 litres). The smallest ocean, the South China Sea, has a volume of 9,880,000 cubic kilometres (both estimates have a precision of 1%).
Two years before Bacharach and David’s paper, Mishima and coworkers had determined the volume of a human tear to be 7 µl (Mishima S et al. Invest. Ophthalmol Vis Sci. 1966). To a first approximation, then, the South China Sea would need more than 1x1024 human tears to fill it.
If we postulate that a very upset person were to cry 5 tears per minute, then they would have to cry for 5x1017 years to fill this smallest of oceans. For reference, the age of the known universe is around 1.4x1010 years. The entire current population of earth would have to be heartbroken, and crying since the Cretaceous, for Carpenter and colleagues’ hypothesis to have a chance of passing peer review.
It is high time that authors in the field of popular music paid more attention to the body of literature that exists, and indeed began to perform adequately designed and controlled experiments. Readers are welcome to share similar examples of erroneous or unfounded claims in in the literature.
Richard P Grant is a London-based writer and troublemaker
