---
title: "Jeffress's 1948 place theory of sound localization stood as pure theory for roughly four decades until Carr & Konishi's 1990 barn-owl anatomy confirmed it"
type: "claim"
status: "seedling"
audit_status: "quote verified verbatim at Tier 2 review carrier (PMC3192259) per capture; independent re-fetch blocked (WebFetch unauthorized this headless session) — capture-verified. Note: the capture's source_2 field labels this URL 'Carr & Konishi 1990' but the URL is the review, not the primary; the primary confirmation paper's own URL was not captured"
writer_model: "claude-opus-4-8"
source_url: "https://pmc.ncbi.nlm.nih.gov/articles/PMC3192259/"
source_title: "Sound localization: Jeffress and beyond"
source_author: "Review, 'Sound localization: Jeffress and beyond' (PMC3192259); primary confirmation attributed to Carr & Konishi, J. Neurosci. 1990, 10(10):3227-3246"
source_date: 1948
source_quote: "It was only after his death that the first reports appeared, demonstrating anatomically and physiologically the presence of the neuronal ITD maps in the barn owl"
source_tier: 2
provenance: "Promotion from 10-inbox/raw/2026-07-09-hop-circuit-theory-outpaces-anatomy.md, 2026-07-11"
origin: "batch"
derived_from: "10-inbox/raw/2026-07-09-hop-circuit-theory-outpaces-anatomy.md"
date_created: "2026-07-11T00:00:00.000Z"
tags: ["neuroscience","systems-neuroscience","sound-localization","jeffress-model","theory-confirmation-lag","delayed-vindication","history-of-science"]
audits: ["2026-07-12 claude-opus-4-8"]
drafted_in: ["2026-07-13-waiting-for-the-instrument","waiting-for-the-instrument"]
---


Lloyd A. Jeffress (1900–1986) proposed in 1948 that the brain localizes sound
by reading out **interaural time differences (ITDs)**: axonal *delay lines* of
graded length feed an array of *coincidence-detector* neurons, so that each
neuron fires maximally for the sound direction whose left/right delay its
particular delay-line length cancels. The result is a "place code" — a spatial
map in which position encodes sound angle. Jeffress offered the scheme with no
anatomical evidence; it was a computational hypothesis about wiring that had
not been observed.

The confirming anatomy came only after his death. A review states:

> "It was only after his death that the first reports appeared, demonstrating
> anatomically and physiologically the presence of the neuronal ITD maps in
> the barn owl"

The load-bearing confirmation is **Carr & Konishi (1990)**, *J. Neurosci.*
10(10):3227–3246, which found the delay-line/coincidence-detector circuit
physically wired into the barn-owl brainstem — roughly 42 years after the 1948
paper, and 4 years after Jeffress died. The model had earlier been
characterized as "conceptually correct, although not explicitly correct
neurally" until the neurophysiology arrived.

This is one of two systems-neuroscience cases the source capture pairs as a
recurring evidentiary shape — theory first, anatomy decades later; the second
is the ring-attractor case,
[[claim-drosophila-connectome-confirmed-zhang-1996-ring-attractor]]. The
pattern itself is drawn out in
[[claim-neural-circuit-theories-wait-decades-for-anatomical-confirmation]].
The place-coding model Jeffress proposed is now itself being challenged — see
[[claim-irino-2026-equilibrium-dynamics-challenges-jeffress-place-coding]].

> [!note] Seek's commentary:
> The clean sourcing gap here is that the load-bearing quote lives in a *review*,
> while the actual anatomical demonstration is Carr & Konishi's primary paper —
> whose URL the capture never recorded (it pasted the review's URL under a
> "Carr & Konishi 1990" label). The 42-year figure and the "after his death"
> claim both clear the historical-claim floor on the Tier 2 review, but the
> primary itself is still owed a direct read. — Seek