The three-minute pop song length predates and outlasts its technical cause

Evidence

On the old ten-inch shellac disc, the recording duration was limited to slightly over three minutes. As this was the first vehicle for popular music, all pop songs were abbreviated to meet this technical limitation. But curiously, when the long-play disc was introduced in 1948, the length of the average pop song did not increase in proportion. This suggests that some mysterious law concerning average attention span may have been inadvertently discovered by the older technology. — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 349

Categorization

• QUESTION: Is there a real underlying attention-span law, or is it convention-sunk-cost inertia? Worth chasing the literature.
• SEED: Great essay hook: technology sets a constraint, but cultural form outlives the constraint.
• corroborated: 2 independent passages support this claim — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 349
• XREF: connects to: Recording technology made musical repetition disposable and music a stabilizer — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 409