---
slug: efference_copy_self_signal_cancellation
name: Efference-Copy Self-Signal Cancellation
one_liner: "A controller broadcasts a copy of its own command to a monitor that predicts and subtracts the self-caused portion of an incoming signal, leaving only the externally-caused remainder."
type: prime
schema_version: 2
status: density_v2_draft
categories: [computational, biological, structural]
origin_domain: sensorimotor_neuroscience
alternate_origin_domains: [telecommunications, immunology, control_theory]
aliases: [self_signal_subtraction, reafference_cancellation, command_copy_prediction, self_versus_other_gating, corollary_discharge_generalized]
related: []
solution_archetypes: []
review_flags:
- "OPERATOR-DERIVED (op-05 generalization) — the proposed GENUS of `efference_copy` (lift: strip the sensorimotor / neural vocabulary, leaving the bare pattern that a controller broadcasts a copy of its own command to a monitor which predicts and cancels the self-caused portion of an incoming signal). Discovered in the op-05 remaining-strata sweep 2026-07-03. Tier B candidate (B-rest): sonnet-proposed genus generalizing a single named input; controller-broadcasts-copy-to-cancel-self-caused-signal spans neuroscience/telecom/immunology distinctly; flagged as distinct from predictive_coding. STATUS: HOLD pending owner keep/cut."
- "Created 2026-07-03; STUB ONLY (frontmatter + Core Idea + Notes). SI/SF/similarity are PROPOSER ESTIMATES pending triangulation. Body sections (Structural Signature onward) NOT written."
- "Phase-C action: re-similarity-check vs `efference_copy` AND `predictive_coding` (screen-overlap risk explicitly flagged) and any self/non-self discrimination or feedforward-cancellation primes; confirm it is a genuine genus (covers the efference-copy input AND siblings like echo cancellation and immune self/non-self) and not a domain instance, a restatement of the input, or an alias of predictive_coding; draw a subsumption edge efference_copy→this + sibling edges at incorporation; sync one_liner to a v1 draft per CLAUDE.md before merge."
substrate_independence:
  composite_substrate_independence: 4
  domain_breadth: 4
  structural_abstraction: 4
  transfer_evidence: 4
  reasoning: 'The genus is a clean information-routing structure: a controller that issues a command also sends an internal copy of it to a monitor, which uses the copy to predict the self-caused component of an incoming signal and subtract it, leaving the externally-caused remainder. Stripped of neural vocabulary this is medium-neutral — it describes nervous systems, duplex telephony, immune self-tolerance, and feedback controllers with the same skeleton, so structural_abstraction and domain_breadth sit at 4, well above the framed input `efference_copy`. Transfer evidence is strong (4): the siblings are real, independently-engineered or independently-evolved cancellation mechanisms (echo cancellers, immune self/non-self discrimination, noise-cancelling control) rather than analogies. It falls short of the ceiling only because the pattern presupposes an agent-like *controller that both acts and perceives* and can route a copy internally — a genuine architectural precondition, not a pure relation.'
similarity_to_nearest_existing_prime:
  slug: efference_copy
  similarity: 0.75
structural_framed:
  label: structural
  aggregate: 0.2
  criteria: {vocab_travels: 0.35, evaluative_weight: 0.0, institutional_origin: 0.3, human_practice_bound: 0.15, import_vs_recognize: 0.2}
  rationale: 'The genus carries no evaluative content and is not bound to a human practice: it is a recognizable control/information architecture (route a command copy, predict and subtract the self-caused signal) that appears wherever a system must separate its own effects from the world''s. Its vocabulary generalizes off the neural particulars (efference, reafference), and it is recognized across engineering and biology rather than imported as a doctrine. The mild non-zero criteria reflect its origin as a named neuroscience concept (von Holst & Mittelstaedt 1950; Sperry 1950). Reads clearly structural.'
phase_b_passes_completed: []
---
# Efference-Copy Self-Signal Cancellation

## Core Idea

The genus is an information-routing architecture: *a system that issues a control command also sends an internal copy of that command to a monitoring subsystem, which uses the copy to predict the self-caused portion of an incoming signal and subtract it, so that only the externally-caused remainder is passed on*. It is reached from the input `efference_copy` by stripping the **sensorimotor / neural vocabulary** — efference, reafference, corollary discharge, and the specific case of an organism distinguishing self-generated from world-generated sensation. Lift off the nervous system, and what remains is the bare pattern: *predict-and-cancel your own contribution using a copy of your own command*, applicable to any controller that both acts on the world and senses it.

The load-bearing anatomy has three parts. First, a *controller that both acts and perceives* — a system whose own actions perturb the very signal it must interpret, creating the core problem: incoming input is a mixture of what the world did and what the system itself did. Second, an *internal copy of the command routed forward* to a monitor — critically, this is a *feedforward* branch: the copy is sent at command time, not inferred after the fact from the sensory return. Third, a *predict-and-subtract operation*: the monitor forward-models the self-caused consequences from the copy and cancels them from the incoming signal, leaving the world-caused residual. The characteristic payoff is *clean separation of self from other at low latency*: because the cancellation is feedforward, the system can null its own contribution the instant it acts, without waiting to observe and disentangle the return — which is why you cannot tickle yourself, why a duplex line stays clear, and why control loops stay stable. The characteristic cost/failure is *miscalibration and spoofing*: the cancellation is only as good as the forward model of self-effects, so if the model drifts or the actuator's real effect changes, the system either fails to cancel (self-signal leaks through as apparent external input) or over-cancels (real external signal is subtracted away as if self-caused) — and the residual channel can be spoofed by any external signal that mimics the predicted self-signal.

Read as a genus rather than as a neuroscience mechanism, the same architecture recurs across structurally-unlike domains. In *telecommunications*, echo cancellation in duplex telephony sends a copy of the outgoing signal to an adaptive canceller that predicts and subtracts the echo of your own voice from the incoming line, leaving only the far-end speech — a direct engineered instance of command-copy prediction and subtraction. In *immunology*, self/non-self discrimination is the same shape read biologically: the immune system carries an internal "copy" of self (the repertoire tolerized to self-antigens during development) and uses it to cancel self-reactive signals, so only non-self (world-caused) antigens trigger a response — with autoimmunity as the over-/under-cancellation failure. In *control theory*, noise-cancelling and feedforward-compensation controllers route a model of the commanded actuation forward to subtract its predicted effect from the measured error, isolating the disturbance. The neural efference-copy case is one species; the echo canceller, the immune self/non-self gate, and the feedforward controller are structurally-unlike siblings sharing the identical predict-and-subtract-your-own-command skeleton, which is what shows the lift is real rather than a restatement of the neural input.

## Notes

**Provenance.** Produced by operator 05 (generalization / lift) as the proposed genus of the input `efference_copy`, by stripping the sensorimotor/neural vocabulary to leave the bare controller-broadcasts-copy-to-cancel-self-caused-signal architecture. Surfaced in the op-05 remaining-strata sweep on 2026-07-03. Claimed siblings: echo cancellation in duplex telephony; immune self/non-self discrimination; noise-cancelling feedforward control. Manifest explicitly flags the genus as *distinct from `predictive_coding`*. Manifest tier: B-rest (sonnet-proposed generalization; "controller-broadcasts-copy-to-cancel-self-caused-signal spans neuroscience/telecom/immunology; distinct from predictive_coding").

**For owner evaluation (keep/cut).** The case FOR: this is one of the stronger Tier-B lifts because the siblings are real, independently-arrived-at cancellation mechanisms — echo cancellers are a mature engineering technology, immune self/non-self discrimination is a foundational immunological principle, and feedforward disturbance cancellation is standard control theory — and they share a precise, load-bearing skeleton (a *feedforward* command copy used to predict and subtract self-caused signal), not a loose family resemblance. The input `efference_copy` is genuinely narrower (bound to nervous systems and sensation), so the lift removes a real domain frame. The RISKS, stated plainly for a coinage candidate: (1) **predictive_coding alias risk — the sharpest one, flagged in the manifest** — efference copy is often discussed as a special case of predictive coding (a top-down prediction subtracted from bottom-up input). Kurt must decide whether this genus is genuinely distinct from a `predictive_coding` prime or an alias of it. The proposed discriminator: efference-copy cancellation is specifically *feedforward from a self-issued command* (the copy is a duplicate of an action the system itself commanded), whereas predictive coding is a more general prediction-error architecture whose predictions need not derive from the system's own motor commands. If the corpus's predictive_coding prime already subsumes this, cut and fold in. (2) **coinage risk** — "efference-copy self-signal cancellation" is a sonnet-minted label; judge whether the cross-domain genus is real-and-unnamed or whether the fields (neuro, telecom, immunology) merely rhyme. (3) **restatement risk** — confirm it does not just restate `efference_copy`; the discriminator is coverage of non-neural instances (echo cancellation, immune tolerance) where "efference" and "reafference" have no literal meaning. The sharp keep/cut question: *is "predict and subtract your own command's effect via a feedforward copy" a distinct genus above efference copy — or is it already covered by predictive_coding, making this an alias to cut?*

**At incorporation.** Re-run similarity against `efference_copy` (the input — restatement check) and, critically, against `predictive_coding` (the manifest-flagged alias risk — the decisive check), plus any self/non-self discrimination, feedforward-compensation, or signal-separation primes. If kept as distinct, draw a subsumption edge `efference_copy → efference_copy_self_signal_cancellation` (neural efference copy as one species) and sibling edges to any echo-cancellation, immune-discrimination, or control-theory primes; also draw a boundary/relation edge to `predictive_coding` documenting the feedforward-command discriminator. If judged an alias of predictive_coding, cut and record the fold. Write a v1 draft and sync the one_liner across v1 and v2 per CLAUDE.md before merge.
