Weeks 3-4 · ear · short-term auditory memory
Hear three notes. Wait two seconds. Sing them back.
The rule
pass: ±45¢ + contour exact on 6 of 8
Each trial is heard, held silently for 2 seconds, then sung. Brackets above the dots mark the memory hold; the dots themselves are per-trial pitch error from the target. Emerald inside ±45¢, grey outside. The failure mode at this delay length is contour collapse — three notes flatten into one remembered shape and the middle pitch drifts toward the outer ones.
Hear it first
Same prompt, three outcomes. Listen to the model, then a clean echo after the silence, then a contour-collapse where the middle note drifts toward the edges.
What’s happening.Echoic memory — the verbatim auditory buffer — decays in ~4 seconds. A 2-second delay sits in the middle of that window: long enough that the trace is fading, short enough that accurate recall is possible if the loop closed cleanly the first time. We’re measuring how much your audio-motor binding survives a brief silence.
Why 2 seconds, not 5. Five seconds (phrase-from-memory, Weeks 5-6) flips the test from echoic memory to working memory and recruits different circuitry — chunking, rehearsal, mental imagery. Two seconds is the precise window that probes the audio-motor binding itself: did the pattern get encoded as pitches or only as sound? Untrained adults often drop from ~85% on immediate echo to ~50% at 2-second delay.
Why this is the bridge. Every repertoire lesson downstream — phrase-from-memory, song-from-memory, call-response-variation, a-cappella-resolve-tonic — assumes you can hold a few pitches in mind across a brief silence. If that fails here at 3 notes / 2 s, longer and harder memory lessons compound the gap.
Session ahead
8 patterns · 3 notes per pattern · 2-second silent hold before singing · ±45¢ on each note + contour exact · 6/8 promotes.