Pinna asymmetry creates front-back and elevation cues for directional hearing.

Evidence

The role of the pinna is to influence sound propagation to the ear at high frequencies by creating asymmetry, both front–back and top–down, that helps directional hearing. The cavity leading to the ear canal is called the concha. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 727

Categorization

• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 727