Experiments isolating two-ear advantages must present stimuli over headphones

Evidence

If asked whether two ears are better than one, most people would answer with an emphatic yes! Almost a century of psychoacoustical work has demonstrated small, but consistent, benefits on detection, discrimination, and identification for the same sounds presented to one (monaural) versus two (binaural) ears. These psychoacoustic experiments require presenting sounds over headphones, as freefield measures do not allow presenting identical stimuli to each ear. This is the only way to quantify the benefit provided by having a second, but independent, sample of the same stimulus. Note that these conditions are commonly referred to as monotic (one ear) and diotic (each ear receives an identical stimulus), respectively, and any time the ears receive different sounds, a dichotic stimulus results. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1426

Categorization

• DEFINE: Defines monotic, diotic, and dichotic stimulus conditions — core vocabulary for the binaural hearing literature.