Date: 10/22/2000
Scientists Find How Sound Effects Sight Development
Study Has Implications for the Role of Attention in Brain Disorders
and the Work Environment
UCSD neuroscientists find that attention to sound influences ability to see.
http://www.eurekalert.org/releases/ucsd-unf101600.html
In studies of how people process sound and sight together to make
sense of the complex world around them, neuroscientists at the UCSD School
of Medicine have found that attention drawn to a sound also enhances an
individual's ability to see.
Published in the Oct. 19, 2000 issue of Nature, the study provides
important insights into normal brain activities, and may lead to better
understanding of the role attention plays in dysfunctional neurological
conditions such as attention deficit disorder and schizophrenia. Another
potential application is in the workplace for design of warning systems and
man-machine interfaces where attention is crucial.
The study's lead author is John J. McDonald, Ph.D., a post-doctoral
fellow in the lab of Steven Hillyard, Ph.D., UCSD professor of neurosciences
and study co-author along with UCSD assistant project scientist Wolfgang A.
Teder-Sälejärvi, Ph.D.
"These studies show a stronger linkage between sight and hearing than
previously demonstrated," Hillyard said. "Our results suggest that you will
see an object or event more clearly if it makes a sound before you see it."
McDonald noted that the majority of past studies looked at only one
sense, such as vision or sound or touch. In order to study the role of
attention in more realistic situations and the specific connection between
sound and sight, the UCSD researchers conducted two experiments with 33
volunteers. The subjects were told to indicate whether a dim, obscured light
appeared soon after a sound was presented. The sound and light appeared
either on the same side or on opposite sides of the subject's direction of
gaze. Using a mathematical model called signal detection theory to weed out
guesses by the volunteers, researchers found that the light was detected
more accurately when it appeared on the same side as the sound.
"We found that what people hear significantly influences what they
see," McDonald said. "Researchers have known for many years that the brain
integrates information received from multiple stimuli in the environment,
and ignores nonessential information. What we haven't understood are the
processes that enable us to selectively pay attention to events occurring in
different modalities. In this study, we found that paying attention to a
sudden sound enhances our ability to see visual stimuli that appear at the
same location."
"As we continue to learn how individuals perceive the multiple stimuli
taking place around them, we'll have data from normal brain function to
compare with and help us understand abnormal conditions, such as attention
deficit disorder," McDonald said.
Teder-Sälejärvi added that the findings also hold promise for the
"ergonomic design of warning systems in assembly lines and for other
high-risk work environments such as radar operation. Studies like ours also
may help in the design of man-machine interfaces where focussing of
attention on a primary task is mandatory."
While the results reported in Nature covered the behavioral
performance of subjects, the researchers also recorded the brain's responses
to sound and light stimuli to see whether paying attention to sound
influences neural activity in visual areas of the brain.
"We're now compiling this data to give us a precise measurement of the
moment to moment changes in the visual cortex that arise from paying
attention to sound," McDonald said.
Next steps in the research include more studies of normal brain
function involving different senses and comparisons to individuals with
abnormal brain function.
Source: UCSD Newletter
