February 24, 2004 at 1:00pm
Psychology Room 101, Busch Campus
Dr. Rachel Keen
Umass-Amherst, Department of Psychology
"Cognitive influences on spatial hearing"
In reverberant rooms a listener perceives a sound coming from its source but
simultaneously suppresses reflected sound or echoes. This phenomenon is
known as the precedence effect because the preceding (original) sound is
given heavier weight than its subsequent reflections. Our research has
explored this perceptual process and found that listeners are sensitive to
the acoustic information cotained in the reflected sound even thogh it is
"suppressed". Specifically, information relevant to room acoustics is
processed by the listener and influences perception. Examples of relevant
acoustic information are delay between lead and lag sounds, filtering of the
echo's spectrum, and presence vs. absence of an echo at a particular
location. Listeners' expectations about ongoing input can raise or lower
echo threshold. These findings suggest that the precedence effect is
strongly affected by cognition, which constrasts with most current models of
the phenomenon.