Simulated finger occlusion reduces but does not remove binaural loudness summation.

Evidence

The Silence condition produces a comparable summation effect to the similarly constructed Virtual condition of Expt. 1. However, while the Virtual Finger condition does not result in an abolition of this summation effect, it does result in a substantial reduction in its size (F (1,7) = 102, p < 0.001). — Dijk, Pim van, Physiology, Psychoacoustics and…, 1552

The Silence condition produces a comparable summation effect to the similarly constructed Virtual condition of Expt. 1. However, while the Virtual Finger condition does not result in an abolition of this summation effect, it does result in a substantial reduction in its size (F (1,7) = 102, p < 0.001). In contrast to Expt. 1, the noise stimulus produces a smaller summation effect than the speech stimulus (F (1,7) = 22, p < 0.005). — Dijk, Pim van, Physiology, Psychoacoustics and…, 1552

Categorization

• SEED: The persistence of binaural summation even under realistic occlusion — with largely intact low frequencies — challenges the simple loudness-summation account of binaural hearing.
• QUESTION: Why does real finger occlusion (which leaves low-freq bone conduction intact) shrink the summation effect less than a full silencing? Worth chasing the mechanism.
• corroborated: 3 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1552