Superstitions Without Borders

There is a small, oddly stable catalogue of superstitions that turns up almost everywhere. Knock on wood. Don't walk under a ladder. Avoid the number associated with death. Cover the mirrors when someone dies. Don't put new shoes on a table. Sneeze and someone says something. Salt over the shoulder. A black cat across the path. The same handful of beliefs, in slightly different costumes, recur across continents.

The purpose of this article is not to claim anything about how that came to be. Diffusion, common cognitive architecture, parallel response to similar pressures, lost shared roots — all of these are live possibilities, and the historical record is too thin in most cases to settle the question.

What is worth doing, instead, is taking the *content* of these recurring beliefs seriously and asking a more interesting question: if the same warning keeps surfacing, what kind of underlying observation might it be a folk-language for? Most of what follows is informed speculation, not settled science. It is offered as a way of looking at superstition not as ignorance, but as an early, imprecise data layer about how human nervous systems interact with their environment.

There is a recurring instinct, after speaking aloud something hopeful or boasting about good fortune, to perform a small physical counter-action: knock on a wooden surface, spit (or pretend to) three times, throw a pinch of salt, touch iron. The behaviour is widespread enough that the verbal phrase "knock on wood" survives in cultures where the original ritual has long since faded.

A modest, testable speculation: these gestures may be intuitive interrupts. Cognitive psychology has documented a real cognitive bias — sometimes called *tempting fate* — in which articulating a positive outcome causes a measurable shift in expectation that, in turn, alters subsequent behaviour and perceived risk. A small, abrupt physical action immediately after the boast functions as a pattern interrupt: a deliberate state change that breaks the trance of certainty. Whether or not it influences the outside world, it almost certainly resets the internal one.

A stronger speculation, harder to test: if attention and intention have any of the subtle field-effect properties suggested by intention-experiment research (Radin, Jahn & Dunne), then a confidently spoken positive prediction is also an act of broadcast. The counter-gesture may be a folk-attempt to shield against the broadcast being received by the wrong listener. We are nowhere near being able to confirm or rule this out — but it is the kind of explanation that, if it were ever validated, would account for the gesture's near-universal stability.

Covering mirrors after a death is a custom found in Jewish shiva practice, in parts of Eastern Orthodox tradition, in Chinese folk practice during mourning, in Victorian English households, in some Mexican and Filipino communities, in various Slavic and Roma traditions. The reasoning given by practitioners varies — sometimes the soul might get trapped, sometimes it might be tempted to return, sometimes the bereaved should not be confronted with their own grieving face.

The behaviour itself is interesting regardless of the explanations attached to it. Speculatively, three threads converge:

*The neurological thread.* Acute grief produces measurable changes in the default mode network and in the perceptual systems responsible for face recognition. Bereaved people genuinely report distorted perception of their own reflection in the early days of loss. Removing mirrors removes a real source of additional neurological strain at exactly the moment the brain is least equipped to handle it.

*The acoustic thread.* A reflective surface alters the acoustic and optical environment of a room. Whatever subtle field effects might be associated with a recently dead body — and there are old, persistent reports of unusual electromagnetic readings near recent deaths — would interact with reflective surfaces in unpredictable ways. Removing the mirror simplifies the environment.

*The attention thread.* If part of the function of mourning is allowing the surviving family to disengage from the deceased's image rather than recirculate it, mirrors are a problem because they keep returning the bereaved to themselves. The custom may be a folk recognition that mourning needs an environment of reduced self-reflection, not increased.

None of these explanations requires the others to be wrong. They could all contribute, in different proportions, to a custom whose stability across unconnected cultures is otherwise difficult to explain by chance alone.

Different cultures fixate on different numbers — 13 in much of the West, 4 in much of East Asia, 17 in parts of Italy, 9 in Japanese hospitals — but the *behaviour* is consistent: an integer is identified as unlucky, and significant effort is invested in avoiding it. Buildings skip the floor. Hospitals skip the room. Wedding planners avoid the date.

Where the unlucky number originates is sometimes traceable (the Japanese 4 sounds like the word for death; the Western 13 has multiple competing origin stories). What is harder to explain is *why the behaviour is so durable* once it appears. Skyscrapers built in 2024 still skip the 13th floor. Korean hospitals still skip the 4th.

The speculative reading: a culturally shared unlucky number functions as a low-cost coordination signal. Once enough people in a population believe a number is unlucky, encountering it in a context like a hospital room or a wedding date produces a measurable spike in cortisol and a measurable decrement in confidence-dependent performance. This is the nocebo effect, and it is real and dose-dependent. The folk avoidance, in that reading, is not irrational — it is an empirical recognition that the number now genuinely *does* carry adverse outcomes for people who hold the belief, regardless of how the belief originated. The superstition becomes a self-reinforcing piece of psychological infrastructure.

Across a strikingly wide range of folk traditions, the same short list of substances and conditions appears as protective: salt, garlic, iron, silver, and the inability of certain perceived threats to cross running water. The threats they are said to protect against vary wildly — evil spirits, malevolent dead, witches, the evil eye, fairies, vampires, bad luck — but the *materials* converge.

This convergence is the part worth speculating about. All four substances share a small set of unusual physical properties:

- Salt is hygroscopic and a strong electrolyte; in solution it dramatically alters local electromagnetic conductivity and produces negative ions as it evaporates. - Garlic is high in sulfur, one of the few common biological sources of paramagnetic compounds, and is among the most broadly antimicrobial substances in nature. - Iron is ferromagnetic and was, in the meteoritic form many cultures considered most sacred, even more so. It distorts and channels local magnetic fields. - Silver is the most electrically and thermally conductive element on the periodic table and the most reflective of the visible spectrum. It is also the most broadly antimicrobial of the metals. - Running water is a continuous, conductive, ionising surface that produces white noise across audible and ultrasonic ranges and disrupts standing electromagnetic patterns.

If there is anything to the persistent suggestion — from poltergeist field reports, from anomalous-magnetometer studies near reported hauntings, from the broader bioelectromagnetics literature — that some of the phenomena folk traditions tried to repel have an electromagnetic component, then the convergence on these specific substances begins to look less like superstition and more like a low-resolution empirical map of the local materials best suited to interfering with electromagnetic effects.

At that point the question is no longer *why people believed these things*, but *how a culture without instruments managed to identify, and keep identifying across generations, the small handful of substances that modern physics now describes as having the most unusual electromagnetic and antimicrobial profiles*. We do not have a confident answer to that question. We have an interesting one to keep asking.

A few smaller patterns are worth noting because they share the same speculative shape — a behaviour that recurs more often than chance and that maps, loosely, onto something measurable.

Threshold rituals. Stepping over rather than on the threshold; placing some object — a horseshoe, a mezuzah, a kolam pattern, a guardian figure — at the entrance; not handing things to people across a doorway. Doorways are physical transitions between two distinct electromagnetic environments (inside, with consistent fields from wiring and shielded volume; outside, with uncontrolled ambient fields). Whatever effects field-environment changes have on the human nervous system — and EEG studies confirm there are measurable effects — would be most concentrated in the act of crossing the boundary itself. The folk recognition that thresholds are special is, at minimum, a recognition that the body responds to crossing them.

Sneeze responses. "Bless you," "salud," "gesundheit," "живи" — almost every culture has a verbal response to a sneeze. The ostensible reasons (the soul leaves the body, the heart momentarily stops, the devil enters) vary. The behaviour is constant. A sneeze is a brief, involuntary, full-body reflex involving spikes in intracranial pressure and a momentary disruption of normal autonomic regulation. A short, kind, externally voiced phrase from a nearby person is almost ideally designed to function as a re-entrainment cue — pulling the sneezer's attention back into normal social and parasympathetic activity. The custom may simply be a folk-discovered nervous-system reset.

The number three. Three knocks. Three breaths. Three repetitions of a charm or prayer. Triple deities. Three days of fasting or vigil. Speculation: three may be the smallest number of repetitions that the brain registers as a *deliberate pattern* rather than a random event or a single occurrence. One is an event. Two could be coincidence. Three is signal. If the function of repetition in ritual is to flag intention as deliberate to the deeper layers of the nervous system, three may simply be the practical minimum that does the job.

The honest conclusion is the one rarely written down. We do not know, in most of these cases, why the same small set of beliefs keeps recurring. The speculations above are speculations — some better supported than others, none yet rigorous enough to settle. What we can say is this:

The persistence of these patterns, across populations under no obligation to share them, is itself the data point. Treating that data point as embarrassment to be explained away has not produced much insight. Treating it as a signal whose source is not yet identified has, at the very least, the virtue of matching how we treat unexplained patterns in any other field.

If even one of these recurring superstitions turns out to be a folk-language description of a real psycho-physiological or environmental effect, the practice of paying close attention to which beliefs *keep coming back* will have been worth doing. And if all of them turn out to be artefacts of human cognition rather than the world, the same exercise will have produced an unusually clean catalogue of how the human nervous system tries to make sense of uncertainty. Either outcome is worth more than the dismissal we usually offer instead.