Lloyd A. Jeffress

Lloyd A. Jeffress (1900–1986) was an American psychoacoustician who in 1948 proposed the "place" model of how the brain localizes sound: axonal delay lines of graded length feed an array of coincidence-detector neurons, so that each neuron fires maximally for the interaural time difference (ITD) its delay-line length cancels, and sound direction is read out as a position in a spatial map. He offered the scheme as a computational hypothesis with no anatomical evidence; the confirming circuitry (Carr & Konishi, barn owl) did not arrive until roughly 1990, four years after his death.

Within this vault Jeffress is the anchor of the sound-localization thread and a recurring case in the "theory-confirmation-lag" pattern — a theory that stood as pure mathematics for four decades before its anatomy was found. His 1948 model is also the incumbent that Toshio Irino's 2026 equilibrium-dynamics preprint is measured against: the whole question of whether that preprint "supersedes" Jeffress or merely re-describes a Jeffress-family circuit's readout turns on what his model actually claimed.

References

• claim-jeffress-1948-place-theory-waited-decades-for-anatomical-confirmation — the 1948 place theory and its ~42-year wait for Carr & Konishi's barn-owl anatomy.

• claim-irino-2026-equilibrium-dynamics-challenges-jeffress-place-coding — the 2026 preprint proposing to replace place-coding with population equilibrium dynamics.

• claim-irino-2026-model-inherits-jeffress-cross-correlation-front-end — how much of the Jeffress-family circuit that 2026 model actually keeps.

• claim-irino-2026-model-offers-no-new-anatomically-distinguishable-prediction — why the challenger, unlike Jeffress, hands the anatomist no target.

• claim-neural-circuit-theories-wait-decades-for-anatomical-confirmation — the cross-domain delayed-vindication shape Jeffress's case helps define.

• observation-hawks-jeffress-cosine-pairing-is-embedding-false-friend — a separate appearance of Jeffress's name in the vault's embedding-collision work.

• 2026-09-26: a vault_bridge probe paired Jeffress's 1948 sound-localization work with Barak Pearlmutter's acoustic source-separation research at cosine 0.74, bridge_candidate: true; a targeted check found no documented connection — shared subject vocabulary ("sound localization"), not a citation or real link. Recorded as a negative so the false lead is not re-run. (from 10-inbox/raw/2026-09-21-hop-pearlmutter-ad-survey-disciplinary-bridge.md)