Auditory Illusion

This is not a primitive Walkman but a pseudophone, clamped like a
nutcracker on the skull of its inventor, psychologist Paul T. Young, Ph.D.
In 1928, Young constructed the pseudophone to monitor "stimulus
distortion" and designed the instrument to alter the location from which
a noise seems to originate. The pictured pseudophone is composed of two
ear trumpets crafted from hearing aids.

The electronic version was invented at mid-century by Raymond C.
Bice, Ph.D., who taught psychology at the University of Virginia until
his retirement in 1994. Bice used the pseudophone to demonstrate the
brain's localization of sound, and the instrument became such a classroom
staple that it was nicknamed the "Bice device." He substituted the rubber
ends of toilet plungers for hearing aids to achieve the trademark
auditory illusion. Many a UVA pupil floundered in search of a sound's
true point of origin, much to the amusement of their intro psych
classmates.