Department of Speech and Hearing Sciences

Hearing and Communication Laboratory

The Hearing and Communication Laboratory (HCL) is a fully-equipped facility for the study of human auditory capabilities. It has four listening stations, a system for synthesizing and presenting simple and complex test sounds, and two off-line developmental systems for data analyses and for programming new experimental routines.

Current HCL projects include studies of the discrimination and identification of complex auditory patterns.

Stimuli employed include laboratory "engineered" sounds, such as tonal sequences, profiles, and ripple noise, etc.; nonsense syllables, words and sentences; and environmental sounds such as cars starting, doors closing, electric saws, water pouring, etc.

Many HCL studies are designed to learn the acoustical properties that determine the discriminability or identifiability of specific sounds for normal-hearing or hearing-impaired listeners. Other investigations are focussed on the range of individual differences in auditory abilities, and on the degree to which strengths or weaknesses in one auditory ability can predict those in another.
Several recent studies have revealed a remarkable difference between the ability to perceive speech vs. the abilities to discriminate nonspeech laboratory sounds, or nonspeech sounds that occur naturally in the environment. While speech may not have any special properties as a stimulus at the level of the cochlea, these studies show that listeners can be quite skilled at speech perception under difficult conditions, while being only average or well below average at the discrimination of nonspeech sounds.

Another current study, the Benton-IU Project is being conducted in collaboration with several other faculty members from SPHS, together with faculty from the the IU School of Optometry. In this study we are attempting to identify sensory (auditory and visual), cognitive and linguistic factors that predict academic success or failure in the first three grades. The subjects are all students entering the first grade in four grades schools in the Benton County Community School Corporation, in Benton County, Indiana.

These studies are funded by awards from NIH/NIDCD, and from Indiana University.