Science, And The Benefits And Costs Of Nose-Picking

Thursday, 17 November 2022, 12:34 pm
Article: Keith Rankin

If ... gets up your nose, picket.*

This month, Radio New Zealand listeners were treated to not one but two science stories about nose-picking! They make good fodder for a discussion about the practice of science.

Self-Vaccination?

The first item – Science: Fun-seeking bees, nose-picking primates, death-telling smartphones – was on 2 November, with Siouxsie Wiles. The 26 October 2022 academic story referred to here (A review of nose picking in primates with new evidence of its occurrence) is: "Nose picking (rhinotillexis) is a common behaviour in humans which remains, however, poorly studied. Several species of primates are known to pick their nose and ingest the nasal mucus suggesting that this behaviour may actually be beneficial and showing it is not restricted to humans."

True to media form – ie the impulse to editorialise – the by-line for the podcast refers to the "bad habit of picking and eating what they find up their nose", even though the story referred to suggests that it might be a good habit!

Siouxsie Wiles says: "Another study starting with an observation … Actually [nose-picking] is quite common in primates … so as for why people and animals might pick their noses, there's lots of speculation … maybe it's something to do with our immune systems, maybe 'self-vaccination'." While the key observation is that nose-picking is a widespread practice, the scientific paper pays particular attention to the habits (and physiology) of a group of lemurs who take the practice to an extreme level.

This story represents good science, because it starts with an observation which raises an immediate question: 'Does nose-picking benefit primates?'; and that question's corollary, given that humans are primates, 'Does nose-picking benefit humans?'. The scientific process here doesn't seek to extend the observational stage; rather it moves on to the all-important speculative (ie hypothetical) stage which is the essence of good unapplied science. Science is, more than anything, a creative discipline. Its essence is speculation: though not 'idle' speculation; some observation should come first.

We should note that the observation of an enduring habit – for example, nose-picking – doesn't necessarily mean there is a benefit. It could be that it's just a habit that is neither beneficial nor costly; but even then, if primates just do it for fun (even just a little bit of fun), then that fun is, of itself, a benefit. And, if the practice turns out to be costly rather than beneficial to primates, there might still be a wider evolutionary benefit; namely a costly practice to one species may provide a benefit to that species' host or habitat, and therefore an indirect long-term benefit to the species. If a practice survives for a long time, then – one way or another – it is likely to be beneficial, even if the only benefit is 'a bit of fun'.

The final stage of the scientific process is the 'empirical testing' phase, the phase that creates the best possible opportunity to disprove a hypothesis. In the above example, the story hasn't reached the testing phase; so the idea that nose-picking confers some form of immunisation benefit to primates is 'undisproven speculation'. It's a plausible working hypothesis though. And if the authors knew of – or could have thought of – a better hypothesis, then they probably would have. Scientific 'truth' is the most plausible (and robust) undisproven explanation for some observation; it is not absolute truth in the way that mathematics is.

In this regard, it is pertinent to note the role of hormesis in enhancing a person's life-expectancy. Hormesis is a concept which featured in the NZ Listener article 'Elixir of Youth' (12 Nov 2022); an article discussing Nicklas Brendborg's book Jellyfish Age Backwards. The idea is that small exposures to stressors teach our bodies to manage stresses, creating degrees of immunity to all sorts of potentially harmful (indeed fatal) traumas, such as (but not only) attacks by viruses.

In this context, Siouxsie Wiles said on RNZ earlier this year (23 Feb): "The lower the dose [of the Covid19 coronavirus] you get, the easier time your immune system will have at getting rid of the virus." Low-dose exposures would be examples of hormesis; so, getting a low dose of a stressor such as a pathogenic virus would be better than getting no dose of that virus.

Before moving on to the second story, we should note that the featured practice – by a group of lemurs – was to extract material from the upper nose and to then swallow that material. There are other aspects of nose-picking which could enhance the flow of micro-organisms to or through the body; in particular, the introduction of organisms from previously touched surfaces. We also need to note that the actual benefit of a practice may not arise from the more obvious aspect of that practice; for example, the benefit arising to the lemurs – if any benefit – may have arisen from the injection of material into the nose rather than from the extraction and ingestion of material from the nose. When a beneficial habit has multiple aspects, it may be only one of those aspects which is beneficial; further, another aspect of that habit may be harmful, though it is almost certain that an enduring habit has net benefits for the evolutionary success of a species.

Dementia?

The second story was on Sunday Mornings, 6 November 2022, James St John: picking your nose may increase risk for Alzheimer’s and dementia. And there was a follow-up the following week: James St John: your nose-picking questions answered.

This story illustrates a number of suspect practices in science, or at least by scientists. And the author intimates the ongoing difficulties with scientific practice.

At first sight, the two stories are contradictory; nose-picking is 'good for you' in the first story but 'bad for you' in the second. But a habit can be both 'good' and 'bad'; though, as noted, the survival of a habit suggests that the good prevails over the bad. It should also be noted that the stories look at two very different aspects of nose-picking; the first story focuses on the ingestion of 'nose-matter' whereas the second sees the nose as a passageway through which harmful bacteria may reach the brain.

The James St John story starts (2'40" into the podcast) with an observed "association" (ie correlation): a type of chlamydia bacteria is significantly present in the brain plaque of people who have died with Alzheimer’s disease. (Presumably the observation is 'sound'; namely that people with the same age profile who have died without Alzheimer’s have been observed to not have anything like the same levels of chlamydia bacteria.) Correlations turn out to be coincidences in some cases, though it looks like coincidence can be ruled out here.

Non-coincidental correlations commonly may have three plausible interpretations. In the case, first is the possibility that the chlamydia bacteria caused the bacteria. Second is the possibility that otherwise diseased tissues served as an excellent habitat for the bacteria; ie causation is reversed. Third is a variation of the second; in this case the bacteria were serving as a defence against the disease, or the disease's excesses. (This latter example is like the case where a war-zone is likely to draw doctors and nurses to the scene; it doesn't mean that this correlation between doctors and death is evidence that doctors are causing the excess deaths of war.)

(A well-known health example of suspect science has been the correlation between cholesterol and heart disease. We now know that there is 'good cholesterol' as well as bad cholesterol, that 'bad cholesterol' arises from means other than the ingestion of animal fats, and that the demonisation of dietary fats distracted us from seeing the dangers of sugar. Many experiments sought to establish causal links from dietary fats to heart disease; many of these were flawed, while other explanation went unexplored.)

In the St John story, an experiment was done on mice, to address this correlation issue. The overdose of bacteria given to mice indeed did harm those mice. It doesn't really tell us much about the context of chlamydia in Alzheimer's victims; certainly, no humans were injected with chlamydia, as the treated mice were.

Science is at its worst when scientists make assumptions which are really culturally-conditioned interpretations. Such assumptions become received 'truths'; when converting interpretations into truths, scientists abuse their authority. (This problem can be particularly bad in forensic science, where expert evidence is used to convict or exonerate a defendant. See this 16 November RNZ story, with particular reference to the 'science' which was responsible for the original conviction: Science: Could a gene mutation help free a convicted killer?)

The assumption of this type mentioned in this story is the 'sterile brain' presumption (4', and especially 17'15" into the podcast). St John narrates that, while it is now-accepted that the brain is full of bacteria, as recently as 10-years ago, it was simply assumed by (most) scientists that the brain was sterile. (This kind of assumption, especially by trusted experts, is common. If we do not know that there are bacteria in healthy brains, they [and hence 'we'] assume that there are not bacteria in healthy brains. It's all about where we put the word 'not' in the sentence. Not-knowing does not mean there is nothing to know.)

This assumption – the sterile brain – constitutes an interesting echo of the scientific interplay between germs and environmental 'miasmas' as the accepted principal source of disease. In the nineteenth century, scientists believed that just about all diseases which we class today as 'infectious' were assumed to be the result of airborne contaminants. The big debate was the extent to which these contaminants ('miasmas', not 'germs') were transmitted from the environment (especially stagnant environments 'soiled' by human waste) or from other people. In the case of the 'other people' explanation ('contagion'), the accepted remedy – tried and tested during outbreaks of Plague – was quarantine. Ineffective quarantines were taken as evidence, even proof, that a disease was not contagious.

While the environmental assumption prevailed (as assumed truth) for most of the nineteenth century, in the years from the 1870s to the 1920s the assumption came to be reversed, as 'germs' replaced miasmas as the 'bad guys' in the disease process. As the germ theory superseded the miasma theory, the emphasis in epidemiology – correctly in many cases – switched to non-respiratory forms of transmission. Plague came to be seen as principally transmitted by fleas, and surfaces (rather than exhaled breath) came to be emphasised as the source of germs. (It was amusing to see in This England, portraying the first months of the Covid19 pandemic in the United Kingdom, how scrupulous people became about hand-washing, and how they continued to mingle unmasked in crowded indoor spaces. And note this RNZ story: You're probably cleaning all wrong, according to science, 22 May 2022.)

Anyway, the twentieth century triumph of the 'germ theory of disease' meant that microbes – for example bacteria, viruses and fungi – came to be seen as 'the enemy' rather than as important parts of the Earth's ecosystems. So, when bacteria were found in the brain, they were 'assumed' by scientists to be a malign presence. The reality of course is that such micro-organisms may be good or bad (or neither) for us; and when they are being bad for us, they may be being good nevertheless for the wider ecosystem.

The central theme of the James St John story is that an excess of bacteria (in, for example, the brain) creates a harmful imbalance, and that such imbalances of excess are the likely causes of conditions such as Alzheimer's. Scientists, biased by their past presumptions, still seem more concerned by imbalances in the form of bacterial surpluses than imbalances in the form of bacterial (or viral or fungal) deficits. It is as plausible that restraint from picking our noses contributes to a dangerous deficit of certain non-chlamydia microbes as it is plausible that nose-picking contributes to a dangerous surplus of chlamydia bacteria. Imbalances can arise from not doing things as well as from doing things.

At the very end of his RNZ interview (17'30") St John states that bacterial imbalances in the brain are likely causes of other conditions (including 'autism'). And he intimates that microbiota in the brain (and elsewhere) are essential (and not just superficial) to good health. Nevertheless, a century-and-a-bit of the predominance of the germ theory has introduced a 'yuck' factor into the assumptions of both the scientific community and the general public; a yuck factor that has been exploited through the effective marketing of cleaning products, and our inclination to 'deep-clean' whenever some pathogen threatens. Interesting cases of 'yucky' but effective medical procedures that we show some reticence towards are maggot therapy (see Medical maggots for wound healing and The curious science of war, both RNZ) and faecal transplants (A coup for poo: why the world’s first faecal transplant approval matters, Guardian, 12 November 2022).

(Note on autism. In its severe form, this is a debilitating condition which manifests as extreme neuro-incapacity, and is almost certainly linked to deficits in the microbiome. However, autism in its almost benign 'neuro-diverse' form has become somewhat fashionable in recent years. While diversity is indeed good, and many more people may be 'on the spectrum' [with emphasis on the high-functioning end of the spectrum] than we hitherto assumed, it is important that these benefits of neuro-diversity do not become a means to minimise the condition in its previously-recognised severe forms.)

Conclusion

The first nose-picking story represented good science, but not the kind of 'science' that purports to distinguish truths from canards. It explains to us why we might be in the habit of doing something, and how that habit might be beneficial despite the yuck factor conditioning us to presume otherwise.

The second story represents both problematic science, and redemption. It indicates how much of what scientists have believed (and still believe) to be 'truth' is really biased interpretation. The redemption is the cognition that scientists can formally overturn formerly-assumed truths; and that the assumptions around the necessity for 'sterile' environments are indeed being overturned, albeit slowly.

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Keith Rankin (keith at rankin dot nz), trained as an economic historian, is a retired lecturer in Economics and Statistics. He lives in Auckland, New Zealand.

* This was a placard in the 'Tania Harris' anti-union protest march of 1983. The '…' in that placard was Federation of Labour president (Jim) Knox.

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Keith Rankin

Political Economist, Scoop Columnist

Keith Rankin taught economics at Unitec in Mt Albert since 1999. An economic historian by training, his research has included an analysis of labour supply in the Great Depression of the 1930s, and has included estimates of New Zealand's GNP going back to the 1850s.

Keith believes that many of the economic issues that beguile us cannot be understood by relying on the orthodox interpretations of our social science disciplines. Keith favours a critical approach that emphasises new perspectives rather than simply opposing those practices and policies that we don't like.

Keith retired in 2020 and lives with his family in Glen Eden, Auckland.

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