Werther Effect

one_liner: The measured rise in suicide rates in the weeks after a publicised suicide, driven by media-modelled behaviour and gated by how closely the at-risk audience identifies with the case, with a sign-flipped protective complement when coverage models recovery instead.

core_idea: The Werther effect is the empirically documented rise in suicide rates following the widely publicised suicide of a celebrity or a high-profile fictional character, concentrated in the weeks after the publicity and in demographic groups that share salient characteristics with the publicised case. Named for the wave of imitative suicides reported after Goethe's 1774 novel *The Sorrows of Young Werther*, its modern formal evidence derives from David Phillips's 1974 cohort analysis of US monthly suicide mortality against front-page newspaper coverage of suicide stories, a finding subsequently replicated across multiple countries and decades. The mechanism is interpreted as a social-learning and cognitive-availability process: media exposure (a) raises suicide's salience as a candidate response to distress — making it more cognitively available — (b) supplies a behavioural script by providing method and context detail, and (c) confers perceived legitimacy or identification when the modelled person is high-status, sympathetic, or demographically similar to the at-risk audience. The effect is bounded by identification: demographically or psychologically closer matches to the publicised case show larger spikes, and geographic or media proximity amplifies exposure. Its complementary finding is the *Papageno effect* — media coverage that focuses on crisis resolution and help-seeking rather than the act itself is associated with *reduced* suicide rates in the following period — which confirms the social-learning interpretation by showing that the modelled outcome, not mere topic salience, is the operative variable. The Werther effect is the principal empirical basis for international responsible-reporting guidelines (WHO and national psychiatric associations) specifying placement, framing, and method-detail conventions for suicide journalism.

scope_of_application:
The Werther effect lives across suicidology and the public-health, clinical, and media-ethics work built on it, governing wherever media-modelled suicidal behaviour reaches identifying at-risk audiences; its reach is bounded to that substance-and-context-bound setting (the imitation mechanism travels far further under its `contagion` / `social_learning` parent — to copycat violence, self-harm, and beyond — where each behaviour's interventions are re-derived rather than inherited from this suicide-calibrated effect).

- **Public-health journalism guidelines** — the WHO and national psychiatric associations publish reporting conventions (avoid front-page placement, avoid method detail, avoid romanticising language) explicitly derived from Werther-effect findings.
- **Suicidology epidemiology** — time-series and quasi-experimental studies of post-publicity spikes are a standard methodology for estimating media-exposure effects on suicide rates.
- **Clinical psychiatry** — contagion considerations shape inpatient management after a unit suicide and community response after a school suicide.
- **Adolescent mental health** — suicide clusters in schools, age cohorts, or geographic areas are read through the same identification-gated contagion mechanism.
- **Media studies and ethics** — the principal empirical reference point for the entire literature on responsible reporting of suicide, paired with its protective Papageno complement.

structural_signature:
**Sig role-phrases:**

- **the publicised modelling event** — a salient, widely covered suicide, especially of a high-status, sympathetic, or culturally resonant person
- **the at-risk audience** — people already in distress whose demographic or psychological profile resembles the publicised case
- **the social-learning channel** — mass or social media carrying the case, with method/context detail and geographic/media proximity as amplifiers
- **the availability-and-script shift** — exposure raising suicide's salience as a candidate response to distress and supplying a behavioural script
- **the identification gradient** — the gate that sets magnitude and locus: spikes concentrate where the audience matches the case, not by raw topic salience
- **the modelled outcome** — the operative variable: whether the *act* or its *resolution* (help sought, crisis survived) is modelled, which fixes the sign of the effect
- **the post-publicity spike** — the measurable rise in suicide rates in the matching group in the following weeks, then decaying
- **the Papageno complement** — the sign-flipped branch: resolution-focused coverage *reduces* rates, proving the modelled outcome (not the topic) is the lever

what_it_is_not:
- **Not driven by mere topic salience.** The harm is not that suicide was *mentioned* but that the *act* was modelled. The complementary Papageno finding — coverage centred on crisis resolution and help-seeking is associated with *reduced* subsequent rates — shows the modelled outcome, not attention to the subject, is the operative variable; if topic salience were the cause, help-focused coverage could not be protective. The concept thus separates suicide-as-topic from suicide-as-modelled-behaviour.
- **Not a blanket case against discussing suicide.** Because the active ingredient is the modelled outcome and the method/context detail, the prescription is about *how* to report — placement, framing, omission of method detail, modelling resolution — not silence. The effect underwrites responsible-reporting guidelines precisely by replacing a taboo with a specifiable form of coverage.
- **Not an unconditional, population-wide rise.** The effect is bounded by *identification*: spikes concentrate in the weeks after publicity and in groups that resemble the publicised case demographically or psychologically, amplified by geographic and media proximity. Coverage of a demographically distant or low-status case is expected to move rates little; the gradient is similarity, not raw exposure.
- **Not coincidence or a generic media panic.** The post-publicity rise is a measured social-learning phenomenon with a temporal signature — availability and script supplied by exposure, then a rise in the following weeks that decays — established by cohort and time-series evidence and replicated across countries and decades, not an impression read off individual cases.
- **Not the substrate-free contagion pattern.** Stripped of "suicide," "media coverage," and "Werther," the residue just *is* `contagion` plus `social_learning` (with an availability/`salience` assist) — publicised behaviour increasing imitation among identifying observers. The Werther effect is one substance-and-context-bound instance; its suicide-specific reporting prescription does not port to copycat violence or self-harm, whose interventions are re-derived from the shared parent rather than inherited from this named effect.

clarity:
Naming the Werther effect makes legible something a diffuse anxiety about "media and suicide" cannot: that the post-publicity rise is a specific, measurable, mechanism-bearing phenomenon, and that two questions usually run together can be answered separately. The first — does publicised suicide raise subsequent rates? — is settled by cohort and time-series evidence and is not a matter of impression. The second — *which features* of coverage drive the rise? — is a distinct, content-analytic question about placement, method detail, and the status and similarity of the modelled person. Holding these apart is what moves the field from "coverage is dangerous" to a locatable set of variables, and reframes the practitioner's question from "should this be reported?" to "in what form, with what placed where?" The effect also pins the operative gradient as *identification*: spikes concentrate where the at-risk audience resembles the publicised case demographically or psychologically, which tells a clinician or journalist that proximity and similarity, not raw topic salience, are what scale the risk.

The decisive clarification comes from pairing the effect with its complement, the Papageno effect, in which coverage centred on crisis resolution and help-seeking is associated with *reduced* subsequent rates. That pairing isolates the operative variable cleanly: if mere attention to suicide drove the harm, help-focused coverage should be neutral or harmful too; that it is protective shows the *modelled outcome* — the script and its resolution — is what shifts, not the topic. So the concept distinguishes suicide-as-topic from suicide-as-modelled-behaviour, and in doing so converts a blanket taboo on discussing suicide into a precise behavioural prescription about how to discuss it. That distinction is exactly the empirical foundation of responsible-reporting guidelines, which specify placement, framing, and method-detail conventions rather than silence — a prescription unavailable until the effect and its complement made the active ingredient legible.

manages_complexity:
The relationship between media and suicide arrives as a tangle of case-specific observations that resist a unified reading: a celebrity's publicised death is followed by a spike, but a clinically identical death reported briefly on an inside page is not; the rise concentrates in some demographic groups and not others; detailed method coverage tracks larger increases; a novel that romanticised the act produced an imitative wave; and — most confusingly for any "coverage is dangerous" intuition — some coverage is followed by *fewer* suicides, not more. Faced with this directly, a journalist, clinician, or epidemiologist confronts a heap of contingent outcomes with no way to predict whether a given piece of coverage will harm, help, or do nothing. The Werther effect compresses the tangle to one mechanism with a small set of controlling variables: media exposure acts through social learning and cognitive availability, so the outcome turns on what is *modelled* — the script and its resolution — gated by *identification* with the modelled person. The sprawling question "what will this coverage do?" collapses to a few measurable features of the coverage and the audience.

With that, the analyst stops cataloguing individual media episodes and tracks the variables the mechanism makes load-bearing: the *modelled outcome* (the act itself versus crisis resolution and help-seeking), the *method and context detail* supplied as a usable script, the *status and sympathy* of the modelled person, and the *demographic and psychological similarity* of the at-risk audience, amplified by geographic and media proximity. From these the direction and size of the effect read off directly, with a clean branch structure. Coverage that models the act, supplies method detail, and features a high-status sympathetic figure who resembles the at-risk audience predicts the largest post-publicity rise; the very same topic covered with the resolution modelled instead — help sought, crisis survived — predicts the opposite sign, the protective Papageno branch. The identification variable sets the magnitude and locus: spikes land where the audience matches the case, so the analyst reads off not just whether rates move but *in whom*. The Papageno complement is what makes the compression airtight, because it isolates the operative variable — if mere topic salience drove the harm, help-focused coverage would be neutral or harmful; that it is protective shows the modelled outcome, not the topic, is the lever. So a heap of contingent media-and-suicide observations contracts to a modelled-outcome term, a method-detail term, and an identification gradient, from which the direction (harmful Werther or protective Papageno), the magnitude, and the affected group are all read directly — which is exactly why the response is a reporting *prescription* rather than a blanket silence.

abstract_reasoning:
The Werther effect licenses reasoning that treats a post-publicity change in suicide rates as the output of media-mediated *social learning* — so the epidemiologist or journalist reasons from what is *modelled*, gated by *identification*, to the direction, size, and locus of the effect, rather than from the mere fact that suicide was covered.

*Diagnostic (read the active ingredient from the spike's sign and location).* The defining inference goes from an observed change in rates back to the features of coverage that produced it. A rise concentrated in the weeks after publicity, in a demographic that resembles the publicised case, is read as social-learning contagion gated by identification — not as coincidence and not as a generic "media is dangerous" outcome. From *where* the spike lands the analyst infers the operative gradient: clustering in groups demographically or psychologically close to the case identifies identification, not topic salience, as the scaling variable. From the *sign* the analyst infers the modelled outcome: a fall in rates after help-focused coverage is read as the Papageno branch, evidence that the script and its resolution, not attention to the subject, did the work. The inference runs rate change + who-and-when → modelled outcome, method detail, and identification, never rate change → "suicide was mentioned."

*Interventionist (set the coverage features, predict harm or protection).* Because the mechanism makes a few coverage features load-bearing, each is a lever with a forecast and a *sign*. Model the act, supply method and context detail as a usable script, and feature a high-status sympathetic figure who resembles the at-risk audience, and the prediction is the largest post-publicity rise. Hold the topic fixed but model the *resolution* instead — crisis survived, help sought — and the prediction flips sign to protection, the Papageno outcome. Suppress method detail, demote front-page placement, strip romanticising frames, and the predicted magnitude shrinks. This is why the practitioner's question becomes "in what form, with what placed where?" rather than "should this be reported?" — each editorial choice maps to a predicted direction and size of effect, and the identification variable predicts the manipulation will bite hardest in the audience that matches the case.

*Boundary-drawing (modelled behaviour, not topic; bounded by identification).* The concept draws two lines it depends on. It separates suicide-as-topic from suicide-as-modelled-behaviour: the harm is scoped to coverage that models the act, and the existence of the protective Papageno complement is the proof that mere topic salience is outside the harmful regime — if attention itself were the cause, help-focused coverage could not be protective. And it bounds the effect by identification: the spike is expected only where the at-risk audience resembles the publicised case, amplified by geographic and media proximity, so coverage of a demographically distant or low-status case is predicted to move rates little. Those boundaries place the effect as a media-mediated, identification-gated instance of behavioural contagion, marking where Werther reasoning applies and where it does not.

*Predictive / ordering and order-of-events.* The mechanism fixes a temporal order — exposure raises availability and supplies a script, then the rise appears in the following weeks and decays — so the analyst forecasts not only whether rates move but *when*. And from the controlling variables the outcomes are rank-ordered before any case: act-modelling plus method detail plus a similar high-status figure predicts the steepest harmful spike; resolution-modelling predicts the protective dip; topic-only or low-identification coverage predicts little movement — direction, magnitude, timing, and affected group all read off the coverage and the audience match.

knowledge_transfer:
Within suicidology and the public-health, clinical, and media-ethics work built on it, the effect transfers *as mechanism* — the same controlling variables (modelled outcome, method/context detail, status and sympathy of the modelled person, and the identification gradient) carry intact across applications. Suicidology epidemiology uses the post-publicity spike as a standard quasi-experimental probe of media exposure; public-health journalism guidelines (WHO and national psychiatric associations) translate the same variables into placement, framing, and method-detail conventions; clinical psychiatry applies the contagion logic to inpatient management after a unit suicide and to community response after a school suicide; and adolescent-mental-health work reads suicide clusters through the identical identification-gated mechanism. The Papageno complement carries with it as the sign-flipped branch, isolating the operative variable everywhere it is applied. The vocabulary — *social-learning contagion*, *cognitive availability*, *modelled outcome*, *identification*, *Papageno effect* — and the responsible-reporting prescription port across that cluster because the substrate is constant: distress-vulnerable human social-learning agents exposed to culturally meaningful media, with method detail and similarity as amplifiers.

Beyond that substrate the honest report is **shared abstract mechanism (B)**, and unusually the parent is already a catalogued prime: the broader pattern is *behavioural contagion via social learning* — `contagion`, refined by `emotional_contagion` and `social_learning`, with an availability/`salience` assist. The Werther effect is one *substance-and-context-bound* instance of that pattern: suicide is the specific behaviour, mass and social media the specific transmission channel, and status-and-demographic similarity the specific contagion gradient. That substrate-bound triple is exactly what makes it a finding rather than a portable structure. So when the cross-domain lesson is wanted — "publicised behaviour increases imitation among identifying observers, gated by the modelled outcome and the similarity of the audience" — it is carried by the contagion / social-learning prime, **not** by "Werther effect," whose distinctive cargo (the suicide subject, the reporting guidelines, the Phillips cohort methodology, the Papageno pairing) is suicidology furniture that does not travel. Strip "suicide," "media coverage," and "Werther" and the residue just *is* contagion plus social learning; no new structural commitment remains.

The neighbouring behaviours make the boundary concrete. Copycat mass shootings, self-harm trends, and other media-amplified imitative behaviours are *siblings* under the same contagion/social-learning parent — genuine co-instances of the general mechanism — but their intervention catalogues (different reporting conventions, different platform-moderation levers, different clinical responses) derive *separately* from the parent for each behaviour, **not** by porting the Werther effect's suicide-specific prescription across. Treating "the Werther effect of mass shootings" as a literal transfer would over-read a suicide-calibrated instrument onto a different behaviour; the correct move is to recognise the shared parent and re-derive the specifics. And further out — a "contagion" of yawns, of financial panic, of fashion — the word travels but only the bare imitation-among-similar-agents skeleton does, which again belongs to the contagion prime, with anything beyond that being analogy. The clean boundary: literal transfer of the Werther effect across suicidology wherever media-modelled suicidal behaviour reaches identifying at-risk audiences; the imitation mechanism travels far further under its `contagion` / `social_learning` parent (to copycat violence, self-harm, and beyond), where each behaviour's interventions are re-derived rather than inherited from this named effect. (See *Structural Core vs. Domain Accent*.)


Westermarck Effect

one_liner: The evolved incest-avoidance mechanism in which people raised in close domestic proximity during the first six years develop a lasting adult sexual aversion to one another — tracking early co-residence as a proxy for kinship, not biological relatedness itself.

status: draft

core_idea:
The Westermarck effect is the psychological phenomenon in which individuals who are raised in close domestic proximity during early childhood — roughly the first six years of life — develop a persistent sexual aversion to one another in adulthood, independent of actual biological relatedness. Edward Westermarck proposed the mechanism in 1891 as an evolved incest-avoidance adaptation: because siblings in ancestral environments almost invariably co-resided in early childhood, tagging early-childhood housemates with sexual aversion provides an effective, relatedness-independent implementation of inbreeding avoidance without requiring the cognitive system to directly detect genetic kinship.

The mechanism is a form of negative imprinting: the early-childhood co-residence window functions as a sensitive period during which the identity of companions is registered, and the registered companions are subsequently marked with sexual aversion that persists into adulthood. The operative cue is spatiotemporal proximity in the domestic context, not genetic relatedness; the evolutionary logic exploits the near-perfect historical correlation between early co-residence and sibship under ancestral conditions, using the former as a proxy for the latter. When the cue and the underlying relationship dissociate — as in cases of siblings raised apart or unrelated children raised communally — the effect tracks the cue, not the biology.

Three independent natural experiments support the pattern. Israeli kibbutzim raised cohorts of unrelated children in shared child-houses; marriage between same-cohort kibbutz peers was virtually absent despite social contact and parental approval. Taiwanese *sim-pua* (minor) marriages paired betrothed children from infancy; those raised together from early childhood showed markedly lower fertility and higher rates of divorce and adultery than other arranged marriages, with the negative outcomes scaling with the duration of pre-adolescent co-residence. Genetic Sexual Attraction studies of adult relatives reunited after childhood separation document the obverse: siblings who did not share early co-residence frequently report heightened mutual attraction, exactly the outcome that early co-residence suppresses.

scope_of_application:
The Westermarck effect lives across evolutionary psychology, kinship studies, and anthropology wherever a sexually-reproducing, mammalian-social organism tags early-childhood cohabitants with adult sexual aversion; its reach is bounded to that reproductive substrate (the developmental-window mechanism travels further as `imprinting`/`critical_period` and the proxy-for-target architecture as `cue_substitution`, neither under the named effect's banner).

- **Evolutionary psychology of mate choice and incest avoidance** — the principal worked example of a proximal cue (early co-residence) implementing a distal evolutionary function (avoiding inbreeding depression).
- **Anthropology of the incest taboo** — the argument that the cross-cultural taboo is largely redundant codification of an aversion most members of a society already feel, recasting "nature or culture?" as what each layer independently contributes.
- **Genetic Sexual Attraction studies** — the counselling literature on adults reunited with biological kin, framing reunion attraction as a *missing* proximal cue.
- **Kibbutz and Taiwanese minor-marriage natural experiments** — the classical social-science datasets (near-absent in-cohort kibbutz marriage; low-fertility, high-divorce *sim-pua* marriages scaling with co-residence duration), repeatedly reanalysed.

structural_signature:
**Sig role-phrases:**

- **the early-childhood sensitive window** — roughly the first six years, the critical period during which the cue is registered
- **the co-residence cue** — close domestic proximity, the operative spatiotemporal input, *not* genetic relatedness
- **the cue-substitution architecture** — co-residence used as a proxy for sibship, exploiting their near-perfect ancestral correlation rather than detecting kinship
- **the negative-imprinting tag** — the registered companions marked with persistent adult sexual aversion
- **the duration dose-response** — the graded outcome: aversion (and its downstream low-fertility/high-divorce signature in arranged co-residence pairings) scales with length of pre-adolescent co-residence
- **the cue-failure asymmetry** — the confirming signature: unrelated co-resident peers avoid each other while siblings raised apart (Genetic Sexual Attraction) do not — the tag, not biology, drives the response
- **the distal rationale** — the selection pressure that contributes nothing to a given individual's response: inbreeding depression makes sib-mating suppression adaptive, the *why* behind the proxy

what_it_is_not:
- **Not kinship detection.** The mechanism does not read genetic relatedness; its operative cue is early-childhood co-residence, a spatiotemporal proxy. The standing error is to assume that because the *function* is incest avoidance the *mechanism* must compute kinship — but the dissociation cases (unrelated kibbutz peers who avoid one another, full siblings raised apart who are not averse) show the aversion tracks the cue, not the biology.
- **Not unconditional on co-residence at any age.** The cue is registered only during the early-childhood sensitive period, roughly the first six years; co-residence beginning after that window is predicted not to install the aversion, which is why relatives first brought together as adults are unprotected. Within the window the effect is graded, scaling with the duration of pre-adolescent co-residence rather than switching on all-or-nothing.
- **Not the claim that the incest taboo creates the avoidance.** Locating the aversion in an evolved sensitive-period mechanism re-reads the cross-cultural taboo as largely *redundant* codification of an aversion most members already feel, not as the originating cause of avoidance. The cultural prohibition reinforces a disposition the mechanism produces; it is a secondary layer, not the explanatory core.
- **Not the substrate-free imprinting or cue-substitution pattern.** Stripped of "sexual aversion," "incest avoidance," and "early co-residence," the residue is "early-exposure-based categorisation yields a stable adult preference" (`imprinting`/`critical_period`) and "an evolved mechanism tags an available proxy that historically tracked the target" (`cue_substitution`). The Westermarck effect is one *implementation* — co-residence standing in for sibship; the distal inbreeding-depression rationale is reproduction-specific and does not generalise, and other species avoid incest through entirely different proxies.

clarity:
Naming the Westermarck effect sharpens the distinction between *distal* and *proximal* explanation that evolutionary psychology rests on. The distal account answers "why does the disposition exist?" — inbreeding depression makes any mechanism that suppresses sib-matings adaptive — while the proximal account answers "what cue actually triggers the aversion in a given individual?" — early-childhood co-residence, not detected relatedness. Conflating the two produces a persistent error: assuming that because the *function* is incest avoidance, the *mechanism* must somehow read genetic kinship. The effect makes vivid that it does not, and that the proximal cue is doing all the work. This is exactly what lets the dissociation cases — siblings raised apart, unrelated kibbutz cohorts, reunited adult relatives — be read not as exceptions but as the cleanest confirmations: each is a setting where cue and relatedness come apart, and the aversion tracks the cue.

The label also dissolves a long-running dispute in anthropology over whether incest avoidance is biological or cultural. Once the aversion is located in an evolved sensitive-period mechanism, the cross-cultural incest taboo can be re-read as largely *redundant* codification of an aversion most members of a society already feel, rather than as the originating cause of avoidance — turning "nature or culture?" into the sharper, answerable question of what each layer independently contributes. And it reframes the practitioner's question about any reported attraction or aversion between relatives: not "are they related?" but "did they share the early co-residence window?" — a question about developmental history that the biological one cannot replace.

manages_complexity:
For the student of incest avoidance the raw material is a tangle: cross-cultural taboo codes that vary in their exact prohibited-kin boundaries, clinical reports of attraction between reunited relatives, anomalous low-fertility marriages in Taiwanese household records, the near-absence of in-cohort pairings on kibbutzim, and the background fact of inbreeding depression in offspring genetics. Treated case by case, each demands its own account — a legal historian's reading of the taboo, a counselor's theory of reunion attraction, a demographer's puzzle about *sim-pua* divorce rates — and the cases seem to pull in different directions, some showing avoidance, some showing attraction, some showing mere social convention. The Westermarck effect collapses that sprawl onto a single developmental variable: *did these two people share close domestic co-residence during the early-childhood sensitive period?* Once an analyst tracks that one cue — its presence, its timing relative to the first six years, its duration — the qualitative outcome for any pair reads off almost directly. Shared the window: predict adult sexual aversion, and so predict suppressed in-cohort marriage, depressed fertility and elevated divorce where such pairings are nonetheless arranged, and a redundant rather than originating role for the local taboo. Did not share it: predict no aversion from this mechanism, and so predict ordinary or even heightened attraction, the Genetic-Sexual-Attraction pattern among siblings reunited as adults. The biological relatedness, which a naive account would put at the center, drops out as a separate parameter to track — it matters to the *distal* question of why the disposition was selected, but contributes nothing to predicting a given individual's response, because the mechanism never reads it.

This is the compression: a phenomenon that looks like it should require a kinship-detection theory (with all the machinery that would entail — how does a mind compute genetic relatedness from available evidence?) is reduced to a one-cue sensitive-period rule plus a fixed evolutionary rationale for why that cue was chosen. The branch structure is binary and the cue is observable in a person's developmental history, so the analyst substitutes a question about who-lived-with-whom-and-when for an intractable question about who-is-related-to-whom-and-how-the-mind-could-know. The dissociation cases that would be baffling anomalies under a relatedness-reading — unrelated kibbutz peers who avoid each other, full siblings raised apart who are drawn to each other — become the *expected* readings off the single cue, and the cross-cultural variation in taboo codes is relocated from the explanatory core to a secondary cultural layer whose job is reinforcement. What had to be re-derived per society and per case becomes one developmental parameter with a predictable two-way split.

abstract_reasoning:
The Westermarck effect licenses reasoning that substitutes a question about *developmental history* for a question about biology — so the analyst reasons from one observable cue, early-childhood co-residence within the sensitive period, to adult sexual aversion, and never from genetic relatedness, which the mechanism does not read.

*Diagnostic (read the cause of aversion or attraction from the cue, not the kinship).* The defining inference goes from an adult outcome back to the developmental cue that produced it. A strong mutual sexual aversion between two adults is read as evidence that they shared close domestic co-residence in the first six years — whether or not they are kin — because the operative cue is spatiotemporal proximity, not relatedness. The signature power of the concept is in the *dissociation* cases: unrelated kibbutz peers who avoid one another, and full siblings raised apart who are drawn to one another, are diagnosed not as anomalies but as the cleanest confirmations, each a setting where cue and biology come apart and the aversion is seen to track the cue. So a reported attraction between reunited adult relatives is diagnosed by inferring a *missing* cue — they did not share the early window — rather than by any failure of kin detection. The inference runs adult aversion/attraction → presence or absence of early co-residence, never adult response → detected genetic kinship.

*Interventionist (set the co-residence history, predict the adult disposition).* Because the cue is a developmental input, arranging it is an intervention with a forecast. Raise two unrelated children together through the sensitive period and the prediction is adult sexual aversion between them — so betrothing infants to be raised in the same household (the *sim-pua* arrangement) is predicted to depress the resulting marriage's fertility and raise its divorce and adultery rates, with the negative outcomes scaling with the *duration* of pre-adolescent co-residence. Withhold the cue — separate siblings in infancy — and the prediction is no aversion from this mechanism, leaving ordinary or heightened attraction. Each manipulation of who-lived-with-whom-and-when maps to a predicted adult disposition, and the dose-response on co-residence duration makes the prediction graded rather than merely binary.

*Boundary-drawing (the sensitive window is the regime; cue, not relatedness, is in scope).* The concept fixes its own applicability through two boundaries. Temporally, the cue is acquired only during the early-childhood sensitive period — roughly the first six years — so co-residence beginning *after* that window is outside the regime and predicted not to install the aversion, which is why siblings first brought together as adults are unprotected. Causally, the mechanism is scoped to the *proximal* cue and is silent on biology: relatedness governs only the *distal* question of why the disposition was selected (inbreeding depression makes sib-mating suppression adaptive) and contributes nothing to predicting an individual's response. Holding these apart is what blocks the standing error of assuming that because the *function* is incest avoidance the *mechanism* must read kinship — and it relocates cross-cultural taboo variation out of the explanatory core into a secondary cultural layer that reinforces an aversion most members already feel.

*Predictive / branch-ordering.* Tracking the single cue — its presence, its timing against the first six years, its duration — the analyst forecasts the outcome for any pair before knowing their genealogy: shared the window, predict aversion and its downstream consequences (suppressed in-cohort marriage, depressed fertility, redundant local taboo); did not share it, predict no aversion and the Genetic-Sexual-Attraction pattern. The two-way split, and the dose-response within the aversive branch, are read off developmental history alone, with biological relatedness set aside as a parameter the mechanism never consults.

knowledge_transfer:
Within evolutionary psychology, kinship studies, and anthropology the effect transfers *as mechanism*, because the single developmental cue it isolates — close domestic co-residence during the early-childhood sensitive period — and the distal/proximal split that frames it apply unchanged across the cases. It is the principal worked example of a proximal cue implementing a distal function (inbreeding-depression avoidance) in mate-choice theory; it supplies anthropology's resolution of the incest-taboo debate (the taboo as redundant codification of an aversion most already feel); it frames Genetic Sexual Attraction in the counselling literature (reunion attraction as a *missing* cue); and it is the standard reading of the kibbutz and *sim-pua* natural experiments. The dose-response on co-residence duration carries with it as a graded prediction. The vocabulary — *reverse sexual imprinting*, *sensitive period*, *cue substitution*, *proximal versus distal*, *kin-recognition-by-proxy* — and the diagnostic substitution of who-lived-with-whom for who-is-related ports across that cluster because the substrate is constant: a sexually-reproducing, mammalian-social organism that tags early-childhood cohabitants with adult sexual aversion.

Beyond that reproductive substrate the literal transfer stops, and the honest report is **shared abstract mechanism (B)** lifting to *two* genuine parents at different levels — neither of which is the Westermarck effect itself. The first parent is *imprinting / critical period*: stripped of "sexual aversion," "incest avoidance," and "early co-residence," the residue is "early-exposure-based categorisation produces a stable adult preference," which is imprinting, and that pattern really recurs across substrates as co-instances (filial and sexual imprinting in birds, olfactory MHC-based kin recognition in mice, song-template acquisition in songbirds). The second parent is more abstract — *cue substitution / proximal–distal alignment*: an evolved mechanism uses an environmentally available proxy for the trait of real interest, exploiting their reliable ancestral correlation rather than detecting the trait directly. The Westermarck effect is one *implementation* of that schema (co-residence standing in for sibship); other species implement incest avoidance through entirely different proxies, which is exactly the point — what recurs is the proxy-for-the-target architecture, not the particular proxy. So when the cross-domain lesson is wanted — "an adaptive system tags an available cue that historically tracked the target, and behaves toward the cue, not the target" — it should be carried by the imprinting/critical-period prime (for the developmental-window form) or the cue-substitution prime (for the proxy-architecture form), **not** by "Westermarck effect," whose distinctive cargo (the six-year window, the sexual-aversion output, the incest-avoidance function, the kibbutz/Taiwan datasets) is evolutionary-psychology-of-mating furniture that does not travel.

The boundary the concept itself draws makes the split unusually clean: the effect *already* separates the proximal mechanism (which is what transfers, under its imprinting and cue-substitution parents) from the distal rationale (incest-depression avoidance, which is specific to reproduction and does not generalise). And its own interventions — predicting kibbutz-marriage rates, setting expectations for reunited adoptees, reading *sim-pua* fertility — are kin-mating-specific and do not port; the portable move is the *form* (tag a proxy cue in a sensitive window, behave toward the tag), which the parents carry. The clean boundary, then: literal transfer of the Westermarck effect across the evolutionary-psychology and kinship-anthropology cases wherever co-residence-tagged sexual aversion is in play; and beyond reproduction, the developmental-window mechanism travels as `imprinting`/`critical_period` and the proxy-for-target architecture as `cue_substitution`, not as the named effect. (See *Structural Core vs. Domain Accent*.)


Wettability

slug: wettability

one_liner: Summarise whether a liquid spreads across or beads off a solid into one measurable scalar — the contact angle set by adhesion versus cohesion — factored into surface chemistry and topography, with two discrete roughness regimes.

core_idea: Wettability is the tendency of a liquid to spread across — or bead up and retract from — a solid surface, determined by the relative magnitudes of the adhesive forces between the liquid and solid and the cohesive forces within the liquid itself. The operative measurement is the *contact angle* (θ) that the liquid-vapor interface makes with the solid at the three-phase contact line: a low contact angle (below 90°) indicates that adhesion to the solid dominates and the liquid spreads (hydrophilic, oleophilic), while a high contact angle (above 90°, reaching above 150° for superhydrophobic surfaces) indicates that cohesion within the liquid dominates and the liquid beads into a near-spherical droplet and retreats. Young's equation — relating the contact angle to the solid-vapor, solid-liquid, and liquid-vapor interfacial energies — is the thermodynamic foundation: wettability is the equilibrium geometry that minimizes free energy at the interface given the three surface tensions. Surface topography interacts with surface chemistry to modulate wettability beyond what flat-surface Young's equation predicts: the Wenzel state (liquid penetrates surface roughness, amplifying the intrinsic wettability) and the Cassie-Baxter state (liquid bridges over trapped air pockets, dramatically increasing the effective contact angle) represent two distinct wetting regimes that can be switched between discontinuously by changes in pressure, chemistry, or geometry. The lotus leaf is the canonical natural instance of the Cassie-Baxter superhydrophobic state: nanoscale waxy protrusions trap air beneath water droplets, giving contact angles above 150° and enabling self-cleaning as droplets roll off carrying surface contaminants. Engineered wettability is load-bearing across lubrication (oil-film coverage on bearing surfaces), coating adhesion (paint must wet the substrate it protects), microfluidics (capillary-driven flow depends on wetting angle at channel walls), inkjet printing (ink must wet the receiver sheet without spreading uncontrollably), soldering (molten solder must wet the metal joint), condensation heat exchangers (whether condensate sheets or beads governs heat transfer efficiency), and anti-icing and anti-fouling surface design.

scope_of_application:
Because wettability is a measurable interfacial property — the contact angle of a liquid-solid pair — rather than a substrate-spanning mechanism, it applies wherever its one physical precondition holds: a liquid meets a solid with definite interfacial energies at a three-phase line. The fields below are real, literal uses of the identical construct and its Young-equation/Wenzel/Cassie-Baxter apparatus, not metaphor; the boundary is precondition-reach (a genuine fluid-solid interface) versus the loose "things that mix" over-reading.

- **Lubrication** — oil-film coverage and spreading on bearing and sliding surfaces.
- **Coatings and adhesion** — paint, primer, and protective films wetting the substrate they cover; anti-fouling surface design.
- **Microfluidics** — capillary-driven flow whose advance is set by the contact angle at channel walls.
- **Inkjet printing** — ink wetting the receiver sheet enough to transfer but not so much as to spread uncontrollably.
- **Soldering and brazing** — molten solder wetting the metal joint for a sound bond.
- **Condensation heat exchangers** — whether condensate sheets (filmwise) or beads (dropwise), governing heat-transfer efficiency.
- **Biological and bio-inspired surfaces** — the lotus leaf's Cassie-Baxter superhydrophobicity, insect cuticles, and the engineered self-cleaning and anti-icing surfaces that mimic them.
- **Enhanced oil recovery** — reservoir-rock wettability controlling how readily oil is displaced from pore surfaces.

structural_signature:
**Sig role-phrases:**

- **the three-phase contact line** — the solid-liquid-vapor junction where a droplet meets the surface and the geometry is set
- **the competing forces** — adhesion between liquid and solid versus cohesion within the liquid, whose relative magnitude decides spreading or beading
- **the three interfacial energies** — solid-vapor, solid-liquid, and liquid-vapor surface tensions, the inputs Young's equation balances
- **the contact angle (θ)** — the single measurable scalar that summarises the whole molecular tangle, the equilibrium geometry minimising interfacial free energy
- **the threshold behaviour** — the cut points reading function off θ: spreading below 90° (hydrophilic), beading above, near-total retraction above 150° (superhydrophobic)
- **the chemistry-versus-topography factoring** — the angle split into two independent levers: intrinsic chemistry (flat-surface Young angle) and surface roughness
- **the two wetting regimes** — Wenzel (liquid penetrates roughness, amplifying intrinsic wettability) versus Cassie-Baxter (liquid bridges trapped air, driving the effective angle up)
- **the discontinuous transition** — the regimes separated by a switchable, collapsible boundary (Cassie-Baxter to Wenzel under pressure), making design a state-selection rather than a monotone dial

what_it_is_not:
- **Not a property of the liquid (or the solid) alone.** Wettability is a property of the *pair* at their shared interface, set by the balance of adhesion (between liquid and solid) against cohesion (within the liquid). The same water is hydrophilic on glass and beads on wax; "is this liquid wetting?" is underspecified until the solid — and its three interfacial energies — are named.
- **Not predictable from surface chemistry alone.** The contact angle factors into two independent contributions: the intrinsic, flat-surface angle Young's equation gives from chemistry, *and* surface topography. Roughness can amplify the intrinsic tendency (Wenzel) or override it almost entirely (Cassie-Baxter), so a surface can be far more repellent than its chemistry alone would predict.
- **Not a monotone dial.** The Wenzel and Cassie-Baxter states are *distinct regimes separated by a discontinuous transition*, not points on a continuum, and the transition is switchable and collapsible (Cassie-Baxter can drop to Wenzel under pressure, abolishing superhydrophobicity). Design is therefore *state selection and stabilisation*, not "make the surface more or less repellent"; reasoning that treats wetting as a smooth function of roughness mispredicts.
- **Not adhesion.** Adhesion is resistance to *separation under normal load*; wettability is *initial spreading geometry* at the contact line. They are related interface properties but distinct — a surface a liquid wets readily is not thereby one the cured film resists peeling from.
- **Not a substrate-neutral "affinity" or "compatibility."** The predictive machinery — contact angle, Young's three-tension balance, the Wenzel/Cassie-Baxter regimes — presupposes a fluid-solid interface with definite interfacial energies; remove the physical interface and there is nothing for the equation to operate on. "Organizational wettability" or "data-pipeline wettability" imports only the loose "things that do or don't mix" intuition, which belongs to `compatibility` (with `interface` and `impedance_mismatch`), not to the surface-science property as named.

clarity:
Naming wettability gives surface science a single, measurable handle — the contact angle — on what would otherwise be a tangle of molecular-scale interactions (van der Waals forces, hydrogen bonding, surface chemistry). The concept's clarifying force is that it reframes "will this fluid cover or refuse this surface?" as a question with a thermodynamic answer: through Young's equation, the contact angle is the equilibrium geometry that minimizes interfacial free energy given three surface tensions, so the spreading-versus-beading behavior a practitioner cares about is read off a balance of adhesive forces (liquid-to-solid) against cohesive ones (within the liquid). That turns a qualitative impression of "wet" or "non-wet" into a graded, predictive scalar — below 90° the liquid spreads, above it beads, above 150° it retracts almost entirely — that a designer can specify and engineer toward.

Its sharper service is to separate two contributions that a flat reading conflates: *surface chemistry* and *surface topography*. By distinguishing the intrinsic, flat-surface angle Young's equation predicts from the two roughness regimes — the Wenzel state, in which liquid penetrates the texture and amplifies the intrinsic wettability, and the Cassie-Baxter state, in which it bridges over trapped air and dramatically raises the effective angle — the concept lets a practitioner ask precisely *why* a surface wets as it does, and which lever (chemistry or geometry) to pull. It also makes legible that these are distinct regimes separated by a discontinuous transition, switchable by pressure, chemistry, or geometry — so that designing for self-cleaning, condensation, coating adhesion, or anti-icing becomes a question of selecting and stabilizing a wetting state rather than merely making a surface "more" or "less" repellent.

manages_complexity:
The actual physics at a liquid-solid boundary is a many-body problem of molecular forces: van der Waals attractions, hydrogen bonding, and the specific surface chemistry of the solid all act at once across the contact region, and no designer choosing a coating or a channel wall could compute the outcome by summing those interactions molecule by molecule. Wettability collapses that entire molecular tangle onto a single measurable scalar — the contact angle θ at the three-phase line — and the reason the collapse is legitimate, not merely convenient, is thermodynamic: Young's equation makes θ the equilibrium geometry that minimizes interfacial free energy given just three surface tensions (solid-vapor, solid-liquid, liquid-vapor). The whole sprawl of microscopic forces is thereby summarized in a balance of adhesion (liquid-to-solid) against cohesion (within the liquid), and the practitioner stops tracking the forces and tracks one number. From that number the functional behavior reads off directly along a clean threshold structure: below 90° adhesion wins and the liquid spreads (hydrophilic, oleophilic); above 90° cohesion wins and it beads; above 150° it retracts almost entirely into rolling droplets (superhydrophobic). The qualitative outcome a designer actually cares about — will this fluid cover the surface or refuse it — is read off where θ falls relative to those cut points, rather than re-derived from the chemistry each time.

The compression has a second move that keeps it from over-simplifying: it factors the single angle into two independent contributions a designer can manipulate separately — *surface chemistry* and *surface topography* — and supplies a small branch structure on the topography term. The intrinsic, flat-surface angle is what Young's equation predicts from chemistry alone; roughness then modifies it through one of two discrete regimes, and which regime obtains is the parameter the analyst tracks. In the Wenzel state the liquid penetrates the texture, and roughness *amplifies* the intrinsic wettability (a hydrophilic surface becomes more hydrophilic, a hydrophobic one more hydrophobic); in the Cassie-Baxter state the liquid bridges over trapped air pockets, and the effective angle is driven dramatically upward toward superhydrophobicity largely independent of the underlying chemistry. These are not points on a continuum but distinct states separated by a discontinuous transition that can be switched by pressure, chemistry, or geometry — so the design question is not "make the surface more or less repellent" by some monotone dial but "select and stabilize a wetting state," a low-dimensional decision over which regime to occupy and how to pin it there. With chemistry, the intrinsic angle, and the regime in hand, the designer reads off self-cleaning, condensation behavior, coating adhesion, capillary flow, or anti-icing performance across lubrication, microfluidics, soldering, printing, and heat exchange — the full molecular interaction problem reduced to one scalar, factored into two levers, with a two-state branch on the geometric one.

abstract_reasoning:
Wettability's core inference is thermodynamic and predictive: it lets the practitioner reason from interfacial energies *to* the equilibrium geometry a droplet will adopt. Rather than simulating the many-body molecular interaction, the analyst invokes Young's equation and infers that the contact angle is whatever value minimizes interfacial free energy given the three surface tensions (solid-vapor, solid-liquid, liquid-vapor) — so θ is *derived* from a balance of adhesion (liquid-to-solid) against cohesion (within the liquid), not measured and left unexplained. The reasoning runs forward from known surface energies to a predicted resting geometry, and that single predicted number then yields functional behavior by a threshold inference: below 90° adhesion dominates and the liquid is reasoned to spread (hydrophilic, oleophilic); above 90° cohesion dominates and it beads; above 150° it retracts almost entirely into rolling droplets. The practitioner reads "will this fluid cover or refuse this surface?" off where θ falls relative to those cut points, an inference from one scalar to a determinate wetting outcome.

The diagnostic complement runs the other way — from observed behavior to hidden cause — and its sharpest form is the chemistry-versus-topography decomposition. Confronted with a surface that wets anomalously (far more repellent than its material chemistry alone would predict), the analyst reasons that the single angle factors into two independent contributions and asks which is responsible: the intrinsic, flat-surface angle set by chemistry, or a roughness regime modifying it. The further inference is to identify *which* regime obtains, because the two are mechanistically distinct. If roughness *amplifies* the intrinsic tendency — a hydrophilic surface made more hydrophilic, a hydrophobic one more hydrophobic — the analyst infers a Wenzel state in which the liquid has penetrated the texture; if the effective angle is driven dramatically upward toward superhydrophobicity largely regardless of the underlying chemistry, the analyst infers a Cassie-Baxter state in which the liquid is bridging over trapped air pockets. The lotus leaf is reasoned about exactly this way: contact angles above 150° on a waxy surface point to air trapped beneath the droplet by nanoscale protrusions, hence Cassie-Baxter, hence the self-cleaning that follows as droplets roll off carrying contaminants.

The interventionist reasoning reframes the design task from a monotone dial to a *state selection*, which is its signature move. Because the two roughness regimes are distinct states separated by a discontinuous transition — not points on a continuum — the designer does not reason "make the surface more or less repellent" but "select and stabilize a wetting state, and decide which lever pins it there." This yields two manipulable inputs with predictable consequences: change surface chemistry to shift the intrinsic angle, or change surface geometry to set and hold a regime, engineering the texture so that the liquid bridges (Cassie-Baxter) rather than penetrates (Wenzel). The reasoning is predictive about the levers — alter the chemistry *or* the topography and forecast the resulting wetting state — and about the application that rides on it: whether a condensate sheets or beads governs heat-exchanger efficiency, whether a coating wets the substrate it must protect, whether capillary flow advances in a microchannel, whether a joint takes solder, whether a surface sheds ice.

The boundary on all these inferences has a structural and a substrate component. Structurally, the analyst must respect the *discontinuity*: because the Wenzel and Cassie-Baxter states are separated by a transition switchable by pressure, chemistry, or geometry, reasoning that treats wetting as a smooth function of roughness will mispredict, and the practitioner instead reasons about which side of the transition the surface sits on and how robustly it is held there — a Cassie-Baxter state can collapse to Wenzel under pressure, abolishing the superhydrophobicity. Substrate-wise, the entire apparatus — contact angle, Young's equation, the two wetting regimes — is anchored to a liquid meeting a solid with definite interfacial energies at a three-phase line, so the moves have force precisely where there are surface tensions to balance and a contact angle to measure, and the predictive machinery does not extend to settings lacking that physical interface even where a loose "affinity" intuition might tempt the analogy.

knowledge_transfer:
*Within the home domain — and across the physical sciences and engineering generally — wettability transfers as mechanism, the contact-angle scalar and the full Young-equation/Wenzel/Cassie-Baxter apparatus carrying intact wherever a liquid meets a solid.* Because the construct is anchored to a definite physical interface, it ports *as wettability*, with the same machinery, across every application that turns on whether a fluid covers or refuses a surface: **lubrication** (oil-film coverage on bearings), **coatings** (paint must wet the substrate it protects; anti-fouling design), **microfluidics** (capillary-driven flow set by the wall contact angle), **inkjet printing** (ink wetting the receiver without uncontrolled spread), **soldering** (molten solder wetting the joint), **biological surfaces** (lotus leaves, insect cuticles), **enhanced oil recovery**, **condensation heat exchangers** (sheeting versus beading condensate governing efficiency), and **anti-icing / anti-fouling** surface engineering. In each the same thermodynamic inference predicts the resting geometry from interfacial energies, the same threshold structure reads spreading/beading/retraction off θ, the same chemistry-versus-topography decomposition diagnoses anomalous wetting, and the same state-selection reframing (stabilise Cassie-Baxter rather than let it collapse to Wenzel under pressure) governs design. This is not analogy but literal recurrence of one construct: wherever there are surface tensions to balance and a three-phase contact line to measure, it *is* wettability — making this closest to an instrument/measure that transfers wherever its physical precondition holds, rather than a "mechanism within, metaphor beyond" concept.

*Beyond that physical substrate the honest verdict is (A) metaphor: the named property does not travel, because its predictive machinery presupposes a fluid-solid interface with definite interfacial energies.* The contact angle, Young's equation, and the two wetting regimes have force precisely where there are surface tensions to balance; remove the physical interface and there is nothing for the equation to operate on. So attempted extensions to social or organisational systems — "organizational wettability," "change thresholds," "data-pipeline quality control" — are pure metaphor: they import only the loose intuition of *things that do or do not mix* or *selective barriers*, without inheriting the geometric-and-energetic machinery (Young balance, contact-angle hysteresis, Cassie-Baxter geometry) that makes wettability predictive. What genuinely survives the crossing is not wettability but the more abstract pattern it instantiates — *the affinity between two phases sets the geometry of their contact* — and that pattern is already carried, more accurately, by the catalogue's `compatibility` prime (the general affinity-between-things pattern, of which wettability is the fluid-solid instantiation), supplemented where relevant by `interface` (the boundary the property sits at) and `impedance_mismatch` (the energy-coupling cousin in the same interface-property family). The home-bound cargo that cannot peel away is the domain-specific physics: the contact angle as observable, Young's three-tension balance, the Wenzel and Cassie-Baxter regimes and their discontinuous transition (itself a candidate instance of `bistability`), the superhydrophobic threshold. So the right statement of reach is: wettability transfers literally, as itself, across the physical sciences wherever a liquid-solid interface exists; beyond that substrate it is metaphor, and the cross-domain "affinity at an interface" lesson belongs to `compatibility` (with `interface` and `impedance_mismatch`), not to the named surface-science property (see *Structural Core vs. Domain Accent*).


Wholesale-Funding Run

one_liner: A rapid, self-reinforcing withdrawal of short-term funding by a small set of professional creditors who simultaneously refuse to roll over maturing liabilities — coordinated by shared information and driven by the first-mover advantage of a finite liquid-asset pool, draining a firm in days.

core_idea:
A wholesale-funding run is a rapid, self-reinforcing withdrawal of short-term funding from a financial institution by a small number of professional creditors — other banks, money-market funds, repo counterparties, ABCP investors — who simultaneously refuse to roll over maturing liabilities rather than accept re-exposure to a counterparty they now doubt. Unlike a classic retail bank run, in which many small depositors act largely independently and the pace of withdrawal is constrained by the logistics of queuing, a wholesale run is effectively coordinated by default: professional creditors share the same information, monitor each other's behaviour in real time, hold funding in large concentrated tranches with short contractual maturities (often overnight to 30 days), and face acute first-mover advantages because an institution's liquid assets are finite and the first creditors to withdraw are paid in full while later ones face losses if the institution fails. The result is that a wholesale run can drain an institution of its entire funding base within days of an initial confidence shock — orders of magnitude faster than any retail run — even when the institution's long-term assets retain positive value.

The structural mechanism is a maturity-transformation and concentration problem with a coordination equilibrium. The institution borrows short to lend or invest long, relying on creditor willingness to roll at maturity; its short-term liabilities are concentrated among a small enough set of sophisticated counterparties that any one of their decisions to withdraw meaningfully changes the incentive calculus for the others. Once a threshold number of creditors refuse to roll, the institution's residual liquid assets are insufficient to meet remaining claims at par, rationally inducing each remaining creditor to withdraw before the asset pool is further depleted — a self-fulfilling dynamic that the 2008 repo runs on Bear Stearns and Lehman Brothers exemplified, where funding evaporated over days with no retail-depositor involvement and no classic bank-run visible in publicly reported deposit figures.

scope_of_application:
The wholesale-funding run lives across the funding channels of banking and liquidity where long-duration assets are funded on call by concentrated professional creditors; its reach is bounded by that funding-on-call mechanic, and the bare coordinated-exit-cascade skeleton (platform exoduses, supplier pullouts) travels under the parents `bank_run`, `information_cascade`, and coordination-with-multiple-equilibria, not under this concept.

- **Tri-party repo** — the canonical channel: repo-market runs on broker-dealers (Bear Stearns and Lehman in 2008), where counterparties refuse to roll, demand additional haircuts, or move custodied assets within days.
- **ABCP conduits** — asset-backed commercial-paper funding withdrawal in 2007–08, as investors declined to roll short-tenor paper backing long-dated conduit assets.
- **Money-market funds** — the "breaking-the-buck" cascade after Lehman, a wholesale run on the funds themselves by their own redeeming investors.
- **Commercial-paper markets** — episodes where short-term corporate funding froze as professional buyers stepped back in concert.
- **Cleared-derivatives margin** — initial-margin spikes that drain liquid resources on a confidence shock, an analogous funding-on-call channel.

structural_signature:
**Sig role-phrases:**

- **the maturity-transformed balance sheet** — long-duration assets funded by short-duration liabilities, relying on creditor willingness to roll at maturity
- **the concentrated professional creditors** — a small set of sophisticated funders (banks, money-market funds, repo counterparties, ABCP investors) holding funding in large short-tenor tranches
- **the common-information coupling** — funders share information and monitor each other in real time, so their choices correlate sharply on news
- **the finite liquid-asset pool** — a buffer whose limit means first movers are paid in full at par while laggards face losses if the institution fails
- **the first-mover advantage** — the resulting incentive for each creditor to withdraw ahead of the others before the pool is depleted
- **the confidence shock** — a rating action, counterparty disclosure, or a single peer's collapse that moves enough funders to refuse to roll
- **the rollover-refusal threshold** — once a threshold number decline to roll, residual liquid assets cannot meet remaining claims at par
- **the self-fulfilling drain** — each remaining creditor rationally withdraws, emptying the funding base within days, far faster than any retail run
- **the invisible-run signature** — no retail queue and no movement in reported deposit figures, so the run is legible only in liability-composition variables

what_it_is_not:
- **Not a classic retail bank run.** A retail run is many small depositors acting largely independently, paced by the logistics of queuing. A wholesale run is a *few* sophisticated creditors, coordinated by default through shared information and real-time cross-monitoring, draining the funding base in *days* rather than weeks — and leaving no queue at all. The actors, the speed, and the coordination structure all differ.
- **Not driven by the gross volume of short-term funding.** The load-bearing variable is the *composition* of the liability side — funder concentration and funding tenor — not the total. An institution that looks comparably funded to a deposit-heavy peer on a balance-sheet summary can be orders of magnitude more run-prone; reading run-risk off aggregate funding figures misses where the fragility actually lives.
- **Not necessarily a sign of insolvency.** The run can empty a firm whose long-term assets retain positive value: it is a *liquidity* failure produced by the first-mover advantage of finite liquid assets, not a verdict that the asset pool is worth less than the claims. The self-fulfilling drain can destroy a fundamentally solvent institution before its assets can be realised.
- **Not always visible in reported deposit figures.** Because no retail queue forms and the run need not move publicly reported deposits, a supervisor watching for a classic bank run may see nothing while the funding base evaporates. The warning signs live in the liability-composition variables, not the deposit-run indicators — the run is, in this sense, invisible to the conventional gauge.
- **Not the general coordinated-exit pattern itself.** The bare skeleton — informed actors racing for the exit under common information, first movers paid in full — recurs in platform exoduses and supplier pullouts. But those travel under `bank_run`, `information_cascade`, and a coordination-with-multiple-equilibria pattern. The wholesale run's specific cargo — creditors, maturing liabilities, refusal-to-roll, par-order withdrawal, liquidity-regulation correctives — needs the maturity-transformation-on-call structure those analogues lack.

clarity:
Naming the wholesale-funding run surfaces an asymmetry that aggregate funding figures hide: the same gross volume of short-term liabilities is far more fragile when held by a small number of sophisticated, short-tenor creditors than when diffused across many small, long-tenor depositors. The load-bearing variable is the *composition* of the liability side — concentration of funders and tenor of funding — not its total, so an institution that looks comparably funded to a deposit-heavy peer on a balance-sheet summary can be orders of magnitude more run-prone. The concept also corrects a diagnostic blind spot it makes explicit: because a wholesale run leaves no queue of retail depositors and need not move publicly reported deposit figures, a supervisor watching for a classic bank run would see nothing while the funding base evaporates over days. Distinguishing the few-informed-actors variant from the many-uninformed-actors prototype is what lets the analyst recognise the run that has no visible queue.

This reframing yields a sharper, tractable set of questions in place of a full panic model: how many funders must refuse to roll for the institution to fail, what information shock (a rating action, a counterparty disclosure, a single peer's collapse) could plausibly move that many to act in concert, and how front-loaded is the rollover schedule over the coming thirty days? Because the fragility is generated by concentration plus maturity transformation plus the first-mover advantage of finite liquid assets, the corrective levers follow directly and target those terms — lengthening funding tenor, diversifying wholesale funders, sizing liquidity coverage and lender-of-last-resort facilities for wholesale rather than only retail withdrawal. The concept thus tells the supervisor where run-risk actually lives and which dial moves it.

manages_complexity: Assessing whether an institution is run-prone is, in full generality, a forbidding modelling task: it would require a complete account of every creditor's beliefs, the cross-monitoring among them, the news flow that might shift confidence, and the path-dependent dynamics of a panic. The wholesale-funding run compresses that into a few balance-sheet-side parameters a supervisor can actually read. Rather than estimate a full panic model, the analyst tracks the *composition* of the liability side — the concentration of funders and the tenor of their funding — plus the first-mover threshold set by the size of the institution's liquid-asset buffer, and reads off run-fragility directly: highly concentrated, short-tenor wholesale funding against a finite liquid pool is acutely fragile; diffuse, long-tenor retail deposits against the same pool are not, even at identical gross volume. This collapses a high-dimensional question into three crisp ones that follow straight from the concentration-plus-maturity-transformation-plus-first-mover mechanism — how many funders must refuse to roll for the institution to fail, what information shock could plausibly move that many to act in concert, and how front-loaded is the rollover schedule over the coming thirty days. The same compressed parameter set immediately localises the corrective levers, since each maps to one term the mechanism names — lengthen tenor, diversify funders, size liquidity-coverage and lender-of-last-resort facilities for wholesale rather than only retail withdrawal. It also corrects a diagnostic blind spot the compression makes legible: because this run leaves no retail queue and need not move publicly reported deposit figures, the relevant warning signs live in the liability-composition variables, not in the deposit-run indicators a supervisor would otherwise watch — so the analyst tracks the few load-bearing dials that govern the qualitative outcome instead of attempting to forecast the panic itself.

abstract_reasoning:
The wholesale-funding run licenses a set of bank-liquidity inferences, all keyed to the *composition* of the liability side — funder concentration and funding tenor — rather than its gross total, and to the first-mover threshold set by finite liquid assets.

*Diagnostic (read run-fragility off liability composition, not balance-sheet volume).* The signature move is to look past the gross volume of short-term liabilities to who holds them and at what tenor. The analyst reasons FROM "this funding is concentrated among a few sophisticated, short-tenor creditors (repo counterparties, money-market funds, ABCP investors)" TO "it is acutely run-prone, because each one's decision to withdraw meaningfully shifts the others' incentive calculus"; FROM "diffuse, long-tenor retail deposits against the same liquid pool" TO "low fragility, even at identical gross volume." The load-bearing inference inverts the balance-sheet reading: an institution that looks comparably funded to a deposit-heavy peer can be orders of magnitude more fragile, and the fragility lives in the composition variables, not the totals.

*Predictive (concentration plus maturity transformation plus first-mover advantage → a self-fulfilling drain in days).* From the mechanism, the framework predicts both the dynamics and the speed of a run. The analyst reasons FROM "a threshold number of creditors refuse to roll, so residual liquid assets cannot meet remaining claims at par" TO "each remaining creditor rationally withdraws before the pool is further depleted — a self-fulfilling cascade," and FROM "funding is concentrated, short-tenor, and finite liquid assets pay the first movers in full" TO "the entire funding base can drain within days, orders of magnitude faster than any retail run." The prediction sharpens to three crisp quantities: how many funders must refuse to roll for the institution to fail, what information shock (a rating action, a counterparty disclosure, a single peer's collapse) could move that many to act in concert, and how front-loaded the rollover schedule is over the coming thirty days.

*Boundary-drawing (the invisible run; few-informed versus many-uninformed).* The framework draws a diagnostic boundary the aggregate figures hide: because a wholesale run leaves no retail queue and need not move publicly reported deposit figures, the analyst reasons FROM "a supervisor watching for a classic bank run sees nothing" TO "the warning signs must be read in the liability-composition variables instead." Distinguishing the few-informed-actors variant from the many-uninformed-actors prototype is exactly what lets the analyst recognise the run with no visible queue — the run that, like the 2008 repo runs on Bear Stearns and Lehman, evaporates funding over days with no deposit-run visible.

*Interventionist (each lever maps to one term the mechanism names).* Because the fragility is generated by concentration plus maturity transformation plus the first-mover advantage of finite liquid assets, the framework predicts the corrective by term-matching. The analyst reasons FROM "lengthen funding tenor" TO "fewer rollover decisions per unit time, so a smaller first-mover advantage"; FROM "diversify wholesale funders" TO "no single withdrawal flips the others"; FROM "size liquidity-coverage and lender-of-last-resort facilities for wholesale rather than only retail withdrawal" TO "the liquid buffer can absorb the concentrated, fast draw." Each dial moves one named term, so the analyst targets the corrective precisely instead of treating run-risk as a monolith.

*Boundary-drawing (the funding-on-call substrate edge).* The inferences require the specific financial plumbing: long-duration assets funded by short-duration liabilities, a concentrated set of professional creditors with frequent rollover decisions, common information that correlates their choices on news, and a liquidation channel whose price impact validates the initial fear. The analyst reasons FROM the absence of the funding-on-call mechanic TO the inapplicability of the rollover-threshold apparatus. The bare coordination-and-exit-cascade skeleton recurs in platform exits, supplier pullouts, and customer mass migration, but those lack the maturity-transformation-on-call structure, so they travel under the broader bank-run, coordination, and information-cascade patterns; the wholesale-run inferences — concentration-plus-tenor fragility, the rollover threshold, the wholesale-sized facility — are bound to the banking-and-liquidity substrate.

knowledge_transfer:
Within banking and liquidity the wholesale-funding run transfers *as mechanism*: the diagnostic (read run-fragility off liability *composition* — funder concentration and tenor — not gross volume), the prediction (a threshold refusal-to-roll triggers a self-fulfilling drain in days), the three crisp quantities (how many funders must refuse, what shock could move them in concert, how front-loaded the rollover schedule), and the term-matched correctives (lengthen tenor, diversify funders, size liquidity-coverage and lender-of-last-resort facilities for wholesale rather than only retail withdrawal) all carry intact wherever long-duration assets are funded on call by a concentrated set of professional creditors. So the apparatus moves without translation across the home domain's funding channels: from **tri-party repo runs** on broker-dealers (Bear Stearns and Lehman in 2008), to **ABCP conduit** funding withdrawal (2007–08), to the **money-market fund** "breaking-the-buck" cascade after Lehman, to **commercial-paper** market episodes and **cleared-derivatives initial-margin** spikes. The instrument and the counterparty type vary; the concentration-plus-tenor fragility, the rollover threshold, and the wholesale-sized facility read the same in each. These are not separate domains but the same banking-and-liquidity plumbing restaged, and the genuinely structural refinement the entry makes — distinguishing the *few-informed-actors* variant from the *many-uninformed-actors* prototype — is itself a within-`bank_run` distinction sharp enough to merit its own slot under that parent.

Beyond finance the honest characterisation is **shared abstract mechanism via the parent prime, not the wholesale-run concept itself**, and the boundary is the *funding-on-call* mechanic. The bare coordination-and-exit-cascade skeleton — *a concentrated set of informed actors, watching each other under common information, races for the exit once a threshold is crossed, the first movers paid in full and the laggards left with losses* — genuinely recurs across substrates as co-instances: flash crowds abandoning a platform, cloud customers mass-migrating on a trust shock, suppliers pulling out of a faltering manufacturer. In each, the *general* pattern travels and travels as mechanism — but it travels as the **parents**, not as the wholesale-funding run. The cross-domain lesson should be carried by `bank_run` (the prototype of which this is the wholesale, informed-counterparty variant), by `information_cascade` (the correlated reading of a common signal), and by a coordination-with-multiple-equilibria pattern (the run as the bad equilibrium of a coordination game). What stays home-bound is the named concept's specific cargo: that the actors are *creditors* with *maturing liabilities*, that the trigger is a *refusal to roll over funding*, that the first-mover advantage comes from *finite liquid assets paid at par in withdrawal order*, and that the corrective is *liquidity regulation and a central-bank backstop*. None of that survives extraction to a platform exodus or a supplier pullout, which have a coordination shape but no maturity-transformation-on-call structure underneath it. So when the cross-domain lesson is needed, the honest move is to invoke the parent — a coordinated exit cascade under common information — and to treat any direct application of "wholesale-funding run" outside the funding-on-call substrate as analogy that has borrowed the run's shape while leaving its financial plumbing, and the specific predictions that plumbing licenses, at home (see *Structural Core vs. Domain Accent*).


Word Frequency Effect

one_liner: The robust finding that high-frequency words are recognised faster and more accurately than low-frequency ones, because lexical access is a graded, exposure-keyed threshold — retrieval speed falling roughly with the logarithm of a word's lifetime corpus frequency for that reader.

core_idea:
The word frequency effect is the robust psycholinguistic finding that high-frequency words — those encountered many more times across a reader's or listener's lifetime — are identified faster and more accurately than low-frequency words, with response-time differences on the order of tens to hundreds of milliseconds in lexical-decision and naming tasks. The effect scales approximately with the logarithm of corpus frequency, is among the most replicated findings in word-recognition research, and persists after controlling for word length, orthographic neighbourhood density, semantic richness, concreteness, and age of acquisition.

The mechanism operates at the level of lexical access: the mental lexicon is not a uniform-access archive but a store in which retrieval speed and accuracy are graded continuously by each item's accumulated exposure history. High-frequency words have lower lexical-access thresholds — they are activated more readily from partial or degraded input — while low-frequency words require more evidence before their representations rise to threshold. This graded-threshold architecture is the core structural commitment of every major word-recognition model that accommodates the effect, from Morton's logogen model, in which each word's threshold lowers with use, to McClelland and Rumelhart's interactive-activation model, in which resting-activation levels scale with frequency, to Bayesian reader models, in which frequency supplies the prior over lexical candidates. The frequency variable is operationalised using corpus norms — Kucera and Francis (1967) established the methodological standard; SUBTLEX corpora provide the current benchmark — and the effect's regression coefficient against log-frequency is a standard dependent variable in word-recognition experiments across visual and auditory modalities and across first and second languages, where the frequency effect is larger in L2, indexing lower lexical entrenchment.

scope_of_application:
The word frequency effect lives across psycholinguistics and its clinical, bilingual, and instructional neighbours wherever a recognizer queries a lexical inventory whose items carry a measurable corpus-frequency distribution; its reach is bounded to that word-recognition substrate (the log-frequency coefficient travels further as a *measuring instrument* wherever a recognizer queries any frequency-distributed inventory, and the underlying retrieval-strengthening law travels cross-domain only under its practice / `learning_curve_effects` parent).

- **Visual word recognition** — the canonical home: the effect drives frequency-norm construction (Kučera–Francis, SUBTLEX), word-recognition models (logogen, interactive activation, Bayesian reader), and stimulus selection in reading experiments.
- **Spoken-word recognition** — the parallel finding in gating and shadowing, where high-frequency spoken words are recognised from less acoustic input.
- **Bilingual and second-language reading** — the *steeper* L2 frequency slope used as a diagnostic of lower lexical entrenchment.
- **Aphasiology and clinical assessment** — the differential preservation of high-frequency words after lexical-access damage as a diagnostic pattern.
- **Reading instruction** — sight-word drills as the interventionist prediction run deliberately, raising an item's effective exposure to slide it toward the high-frequency floor.

structural_signature:
**Sig role-phrases:**

- **the recognizer** — the human reader or listener whose mental lexicon is being queried
- **the lexical inventory** — the store of items, each carrying a measurable corpus log-frequency distribution
- **the exposure history** — the recognizer's accumulated lifetime encounters with each item, the variable that locates it
- **the graded-threshold access** — the core architecture: retrieval speed/accuracy continuously graded by exposure (use-lowered logogen threshold, frequency-scaled resting activation, or frequency-supplied prior), not a known/unknown binary
- **the log-frequency scaling** — the signature: recognition latency falls approximately with the logarithm of corpus frequency, the most-replicated word-recognition finding
- **the residualise-against-frequency instrument** — the methodological payoff: the regression coefficient of RT on log-frequency as a corpus-anchored measuring stick other predictors must survive
- **the covariates to partial out** — length, orthographic neighbourhood, concreteness, age of acquisition — the form-properties held distinct from experience-with-the-form
- **the entrenchment readout** — the slope itself as a diagnostic: steeper in L2 and after lexical-access damage, indexing a thinner, less-entrenched lexicon

what_it_is_not:
- **Not a property of the word's form.** A high-frequency word is not *structurally* easier: TABLE beats TABID not because of anything intrinsic to the string but because this recognizer has met TABLE far more often. The same string is fast or slow depending on the reader's exposure history, so the effect belongs to the *experience-with-stimulus* account, not the stimulus-properties one — and a slow latency is not evidence of a hard form.
- **Not a known/unknown binary.** Recognition is not a switch between words a reader has and has not got; frequency grades a *continuous*, exposure-keyed threshold of retrievability spanning every item in the lexicon. The right question is not "does this reader know the word?" but "how readily does this item rise to threshold for this reader?"
- **Not transient priming.** The frequency term reflects *cumulative lifetime* encounters, not a boost from a recent exposure. A latency drop produced by a just-seen prime is a different, short-lived effect; attributing it to lifetime frequency over-reads the instrument, and the two must be kept apart when residualising.
- **Not a measure of intrinsic difficulty.** The regression coefficient of response time on log-frequency locates an item on an exposure continuum; it does not quantify how hard the word is in any absolute sense. Reading a slow latency as a difficult *word* rather than a low-exposure item *for this reader* mistakes the instrument's reading.
- **Not the substrate-free retrieval-strengthening law.** Stripped of the mental lexicon, corpus norms, and the recognition-task apparatus, the residue — "the more often a representation has been retrieved, the faster it comes up" — is the practice / `learning_curve_effects` / exposure-strengthens-access family, which recurs in motor patterns, expert chess recognition, and code reading. The word frequency effect is the psycholinguistic *exemplar*, distinguished by its exposure being *naturalistic* lifetime encounter rather than deliberate training; the cross-domain law travels under the parent, not this name.

clarity:
The chief clarity the effect brings is dissolving the naive view that a word is simply either *known* or *not known*. Recognizing frequency as a graded determinant of access replaces that binary with a continuous, exposure-keyed threshold of retrievability spanning every item in the lexicon, so the practitioner stops asking "does this reader know the word?" and starts asking "how readily does this item rise to threshold for this reader?" — a question with a measurable answer that the binary cannot pose. It also cleanly separates two causal stories that lexical-decision and naming data otherwise confound: the *stimulus-properties* account (length, orthographic neighbourhood, phonotactics — what is intrinsic to the form on the page) and the *experience-with-stimulus* account (how many times this particular reader has met this particular word). Because frequency belongs to the second, it forces the recognition that the same string can be fast or slow depending entirely on the recognizer's history, not on anything structural about the word.

This makes frequency the variable an experiment must control before any other lexical predictor can be trusted: an apparent effect of concreteness, neighbourhood, or age of acquisition is suspect until it survives partialling out log-frequency, because frequency is correlated with so much else and absorbs so much variance. Naming the effect thus turns a confound into an instrument — the regression coefficient of response time on log-frequency becomes a stable, corpus-anchored measure against which other manipulations are residualised, and its magnitude (larger in L2, larger after lexical-access damage) becomes a readable index of lexical entrenchment rather than a nuisance to be explained away.

manages_complexity:
A lexical-decision or naming dataset is, on its face, a high-dimensional mess. Each item differs on length, orthographic neighbourhood density, bigram and phonotactic regularity, semantic richness, concreteness, age of acquisition, and a dozen lesser form properties, and any of these might be what is slowing a reader on TABID relative to TABLE. Faced with a slow item, an experimenter could be driven to a per-item story — this string is long, that one has few neighbours, this one is abstract — and the field would be a catalogue of idiosyncratic explanations, one per word. The word frequency effect compresses that sprawl by establishing that a single corpus-anchored scalar, log-frequency, absorbs the largest share of the across-item variance. The analyst no longer asks "what is special about this word's form?" first; instead the workflow inverts: residualise response time on log-frequency, and only the variance that *survives* that partialling needs a further account. A whole class of would-be explanations collapses into one regressor with a known sign and an approximately log-linear shape, and the practitioner reads off whether any other manipulation — concreteness, neighbourhood, an experimental prime — is real by whether its coefficient is nonzero *after* frequency is removed.

The compression also runs in the modelling direction. Rather than a separate access theory per word, every major recognition architecture encodes the entire lexicon's retrieval behaviour in one graded parameter — a use-lowered threshold, a frequency-scaled resting activation, a frequency-supplied prior — so that the question "how readily will this item be identified, for this reader, from this much input?" is answered by reading the item's position on a single exposure-keyed continuum rather than by a bespoke calculation. From this one parameter a branch structure follows that an analyst can run forward without re-deriving the lexicon: items low on the continuum are recognised slower and degrade first, so lexical-access pathology should bite low-frequency words earliest; anything that raises a particular item's effective exposure (repetition, priming, sight-word drill, naturalistic re-encounter) should slide it up toward the high-frequency floor and shrink its latency; and a population with thinner exposure histories (second-language readers, less-entrenched lexicons) should show a *steeper* slope, the effect's own magnitude becoming a readable index of entrenchment. What would otherwise be a tangle of item-specific timings and population-specific anomalies reduces to one continuous variable plus a small set of monotone predictions read off its value.

abstract_reasoning:
The word frequency effect licenses reasoning that treats lexical access as a *graded, exposure-keyed threshold* and corpus log-frequency as the scalar that locates any item on it — so the psycholinguist reasons from an item's frequency and a reader's history to recognition speed, and uses the effect's own coefficient as a measuring instrument.

*Diagnostic (read access state and entrenchment from latency, and isolate real effects from confounds).* The defining inference goes from a recognition latency back to the access dynamic that produced it. A reader slow on TABID and fast on TABLE is read not as TABID being structurally harder but as TABID sitting lower on the exposure continuum for this reader — the same string would be fast for a reader who had met it more often, so latency is diagnosed against the recognizer's history, not the form. The effect's *magnitude* is itself diagnostic: a steeper slope of response time on log-frequency reads as a thinner, less-entrenched lexicon (the basis for using a larger frequency effect to index L2 readers and lexical-access damage). And because frequency absorbs so much across-item variance and correlates with so much else, it serves as the confound to subtract first: an apparent effect of concreteness, neighbourhood, or age of acquisition is diagnosed as suspect until its coefficient survives partialling out log-frequency. The inference runs latency → position on the exposure continuum (and slope → degree of entrenchment), never latency → intrinsic difficulty of the string.

*Interventionist (raise effective exposure, predict the latency drop).* Because access is graded by accumulated exposure, anything that raises a particular item's effective exposure is an intervention with a forecast: repetition, priming, sight-word drill, or naturalistic re-encounter must slide that item up toward the high-frequency floor and shrink its recognition latency. Conversely, no manipulation of the form itself changes the frequency term — the lever is the reader's history with the item, not the item. Each exposure-raising manipulation pairs with a predicted reduction in response time bounded below by the high-frequency baseline, and the prediction is monotone in the amount of added exposure.

*Boundary-drawing (frequency is experience, not form; an instrument to residualise against).* The concept draws a sharp line between two causal stories that recognition data otherwise confound — the *stimulus-properties* account (length, orthographic neighbourhood, phonotactics: intrinsic to the form) and the *experience-with-stimulus* account (how many times this reader met this word) — and places frequency firmly in the second. That boundary fixes the workflow: frequency is the variable to control before any other lexical predictor can be trusted, and the regression coefficient of response time on log-frequency becomes a stable, corpus-anchored instrument against which other manipulations are residualised. It also bounds the claim — the effect is a property of how the lexicon is structured and accessed in memory, scoped to recognizers querying a lexical inventory, not a general statement about cognition — so a latency difference driven by form, or by transient priming rather than lifetime exposure, falls outside the frequency account and calls for a different term.

*Predictive / branch-ordering.* From an item's position on the single log-frequency continuum the analyst forecasts a small set of monotone outcomes before testing: low-frequency items are recognised slower and degrade first, so lexical-access pathology is predicted to bite them earliest; raising any item's effective exposure is predicted to move it up the continuum and cut its latency toward the floor; and a population with thinner exposure histories is predicted to show a steeper slope — recognition order, the locus of pathology, and the direction of every exposure manipulation all read off one item's value and the reader's entrenchment.

knowledge_transfer:
Within psycholinguistics and its adjacent areas the effect transfers *as mechanism*, because the graded-exposure-keyed-threshold architecture and the corpus-anchored log-frequency coefficient apply unchanged across the cases. Visual word recognition is the home, but spoken-word recognition shows the parallel finding (high-frequency words identified from less acoustic input in gating and shadowing), bilingual reading uses the *steeper* L2 slope as an entrenchment diagnostic, aphasiology reads the differential preservation of high-frequency words after lexical-access damage, and reading instruction's sight-word drills are the interventionist prediction run deliberately (raise an item's effective exposure, slide it toward the high-frequency floor). The vocabulary — *lexical access*, *log-frequency*, *resting activation / logogen threshold / lexical prior*, *entrenchment*, *residualise against frequency* — and the workflow of subtracting frequency first carry intact across that cluster because the substrate is constant: a recognizer querying a lexical inventory whose items carry a measurable corpus-frequency distribution.

This entry has a genuine **instrument (C)** facet worth marking separately from its mechanism. Beyond explaining latencies, the regression coefficient of response time on log-frequency is a *measuring stick*: a stable, corpus-normed quantity (Kučera–Francis, SUBTLEX) that experiments use to residualise other lexical predictors and to read entrenchment off its slope. As an instrument it transfers *literally* wherever its precondition holds — any recognizer querying any inventory of items with a frequency distribution — and the boundary to police is instrument-reach versus over-reading: the coefficient measures position on an exposure continuum, not "intrinsic difficulty," so reading a slow latency as a hard *form* (rather than a low-exposure item *for this reader*) over-reads it, as does attributing to lifetime frequency what is really transient priming.

The mechanism's beyond-domain report is **shared abstract mechanism (B)**. The genuinely substrate-spanning structure is not the word frequency effect but the more general law it instantiates — *cumulative practice/exposure strengthens retrieval access, with speed graded by (log) exposure*. That law really recurs across substrates as co-instances: high-frequency motor patterns are executed faster, frequently-seen chess positions are recognised faster by experts, common code idioms are read faster by programmers. So when the cross-domain lesson is wanted — "the more often a representation has been retrieved, the faster and more reliably it comes up" — it should be carried by the practice / `learning_curve_effects` / exposure-strengthens-access family, **not** by "word frequency effect," whose distinctive cargo (the mental lexicon, corpus norms, the recognition-task apparatus, the specific covariates to partial out) is psycholinguistics furniture that does not travel. The one nuance distinguishing it within that family is that its exposure is *naturalistic* lifetime encounter rather than deliberate training, which is exactly why it is the psycholinguistic *exemplar* of the broader retrieval-strengthening law rather than the law itself. The clean boundary, then: literal transfer of the word frequency effect across word-recognition and its clinical/bilingual/instructional neighbours; the frequency coefficient travels further as a *measuring instrument* wherever a recognizer queries a frequency-distributed inventory; and the underlying retrieval-strengthening mechanism travels cross-domain only under its practice/learning-curve parent, not under the named effect. (See *Structural Core vs. Domain Accent*.)