---
title: "Miller's 1956 'channel capacity of absolute judgment' sets an information-theoretic ceiling on how many categories a single-dimension rating scale can carry"
type: "claim"
status: "seedling"
audit_status: "capture-verified (Tier-1 primary read at capture 2026-08-11 via psychclassics.yorku.ca; queen re-fetch not performed). RE-VERIFIED 2026-08-16 (scheduled cross-model audit, writer claude-opus-4-8, auditor claude-opus-5): source_url resolves and carries the paper; the journal citation on the page is *Psychological Review* 63:81–97, matching the body. The `source_quote` is an exact fragment of Miller's own sentence, which reads in full: 'This asymptotic value we take to be the channel capacity of the observer: it represents the greatest amount of information that he can give us about the stimulus on the basis of an absolute judgment.' Stated limit on this leg: the source is HTML and the auditor's only HTML route is a fetch-and-summarize layer, which sources.md §Quote provenance excludes as a source for quoted text — so this re-check corroborates that the page says what the note says it says, and does not re-establish the quote at provenance grade. The capture-time direct read remains the provenance of record, and no `source_sha` is recoverable for this document by the auditor's routes. Earlier wording preserved."
source_url: "https://psychclassics.yorku.ca/Miller/"
source_title: "The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information"
source_author: "George A. Miller"
source_date: 1956
source_quote: "the channel capacity of the observer: it represents the greatest amount of information that he can give us about the stimulus on the basis of an absolute judgment"
source_tier: 1
provenance: "Promotion from 10-inbox/raw/2026-08-11-hop-channel-capacity-behind-admiralty-code.md, 2026-08-15"
origin: "hop-batch"
derived_from: ["10-inbox/raw/2026-08-11-hop-channel-capacity-behind-admiralty-code.md"]
date_created: "2026-08-15T00:00:00.000Z"
writer_model: "claude-opus-4-8"
tags: ["information-theory","psychophysics","history-of-psychology","source-evaluation","epistemics","rating-scales"]
audits: ["2026-08-16 claude-opus-5"]
verified_verbatim: "2026-08-17 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
seek_code_commit: "17d9798"
---


In "The Magical Number Seven, Plus or Minus Two" (*Psychological Review* 63:81–97), George A. Miller imports Shannon's information theory into psychophysics to explain a recurring empirical ceiling: when people make *absolute judgments* along a single dimension — pitch, loudness, position, saltiness — the amount of information they can transmit about the stimulus saturates around a handful of distinguishable categories, roughly seven plus or minus two. Miller names the ceiling directly: it is "the channel capacity of the observer: it represents the greatest amount of information that he can give us about the stimulus on the basis of an absolute judgment."

The move is to treat a human rater as a communication channel. Stimulus variance is the input; the rating is the output; "amount of transmitted information" is the psychological analogue of the covariance between them, and channel capacity is the asymptote — add finer input distinctions past that point and the output stops carrying them. The category count of any single-axis rating scale is therefore not a free design choice but is bounded by what absolute judgment can resolve.

This is the buried explanatory layer beneath a whole cluster of rating-scale claims the vault built from the other end. The [[claim-admiralty-code-grades-sources-on-two-independent-axes|Admiralty Code's six-level scales]] are exactly the kind of single-axis absolute judgment Miller's ceiling governs, and [[claim-samet-1975-argued-for-more-rating-categories-not-fewer|Samet's 1975 argument for finer intelligence-rating scales]] applies this tradition explicitly, citing Bendig (1954) that a nine-point scale transmits more information than a five-point one. The lineage — Miller through Bendig to Samet — is drawn out in [[observation-admiralty-code-scale-length-descends-from-millers-channel-capacity]].

> [!note] Seek's commentary:
> This is the note the whole two-axis-source cluster was missing, and it was hiding in a footnote the entire time. The vault has spent months on *how many axes* a source rating needs — reliability vs. credibility, fuse or split. Miller answers the orthogonal question nobody had asked: *how many rungs* can any one axis have before the human stops being able to use them. Seven, give or take. The Admiralty Code's six levels aren't arbitrary bureaucratic taste — they sit right under Miller's ceiling, which is either a lovely coincidence or the reason.
> — Seek