Auditory Acuity Improves through Training, Experiment Implies

Coaxing great performance from an orchestra requires that a conductor combine the talents of interpreter, psychologist, actor, coach, and drill instructor. It also requires a unique auditory ability: the capacity for simultaneously hearing the complete ensemble as well as all its individual performers.

Conductors—the good ones, that is—have long been known to possess a special talent for picking out sour notes from a sea of sweet ones. Is such an ability innate, or does it develop as one grows into the job? According to one recently published study, this capacity for "parallel processing" may actually improve with training.

In an experiment designed to quantify the ability to localize sounds, scientists in the Department of Neuropsychology at the University of Magdeburg in Germany compared the performances of three groups: seven orchestra conductors (average age 45, with 19 years average conducting experience, minimum experience 6 years); seven pianists (average age 43, average professional experience 16 years, minimum experience 7 years); and seven non-musicians (average age 43). The subjects were seated one at a time before an array of six loudspeakers, three in front of them and three to the right side, arranged equidistant from the listener along a 90-degree arc. Eighty-millisecond bursts of bandwidth-limited white noise (500Hz-5kHz @ 75dB SPL) were delivered randomly through all six speakers, infrequently interrupted by wider-bandwidth bursts (500Hz-15kHz). The subjects' brainwave responses were recorded during the experiment by electrodes attached to their scalps.

The subjects were asked to indicate the directions from which the "sour notes" originated. All three groups scored similarly in identifying front sources, but the conductors demonstrated vastly better abilities at identifying peripheral sources. "Although a spatial gradient was evident in all three groups for central auditory space, only the conductors displayed a gradient for the periphery," the study's authors explained. "This improved spatial tuning in conductors also has behavioural consequences, as attested by a significantly reduced false alarm rate for adjacent locations in the periphery." In other words, the conductors were more accurate more often in identifying which of the side speakers was playing.

Scores for identifying peripheral sources were similar for the pianists and non-musicians, leading to speculation that musical training in itself does not improve auditory spatial perception. The conductors' enhanced abilities to localize sounds may be an adaptation to the demands of their jobs.

One implication of this study is that other types of auditory neuroperceptual training, such as that engaged in by audiophiles in the pursuit of their hobby, may enable them to hear more accurately than untrained listeners in certain contexts. The study, Neuroperception: Superior auditory spatial tuning in conductors, appears in the February 1 issue of the scientific journal Nature. A brief synopsis appears in the February 3 edition of Science News.