Listeners remember nuances of musical performances, research suggests

Researcher Caroline Palmer says the study could lead to a better understanding of human memory.       By Jo McCulty

By Yudhijit Bhattacharjee, Research Communications

When we hear a piece of music, our memories record not just the melody that makes up its musical structure. We also remember subtle features like intensity and duration of individual notes, say researchers at Ohio State. This ability appears as early as 10 months of age, according to a new study by the researchers.

These features are what make two musicians sound different when they are playing the same music, and make two speakers sound different when they are saying the same sentence.

Caroline Palmer, professor of psychology at Ohio State, found that people remember such instance-specific acoustic features -- known as prosodic cues -- when recalling a familiar tune. Prosodic cues in music enable listeners to identify a favorite performer or a familiar voice in the same way that characteristics of tone and inflection help listeners recognize individual speakers.

Palmer and her collaborators in the research -- the late Peter W. Jusczyk, a psychology professor at Johns Hopkins University, and Melissa K. Jungers, a graduate student at Ohio State -- reported their findings in a recent issue of the Journal of Memory and Language.

The researchers conducted three experiments to investigate people's memory for music. In the first experiment, 24 musically trained subjects and 16 subjects with no musical training were asked to listen to two short musical sequences played on a computer-monitored acoustic piano. The music was played over and over again to familiarize the listeners with the sequences.

The researchers then played different performances of the same musical sequences to listeners. The new performances were exactly the same as the original sequences in melody and rhythm, but they differed in nuances such as how loud and long certain tones were.

Despite the similarity in musical structure, the listeners were able to distinguish the changed sequences from the familiar ones. The subjects who lacked musical training were just as discerning as those who were musically trained.

"The finding showed that listeners were able to remember specific instances in the performance rather than just the general meaning or the 'gist' of the music," Palmer said.

To find out if the discerning ability of the subjects was due to their years of exposure to music in everyday life, the researchers repeated the experiment with 16 10-month-old babies. When the babies recognized a piece of music, they turned their heads toward the loudspeakers. The babies turned their heads for longer periods when they heard a performance they had been familiarized with than when they were exposed to novel performances. The researchers believe this indicates that they remembered instance-specific features as the adult subjects did.

"We wondered if listeners are equipped from birth with the right perceptual and memory abilities to remember particular musical performances and voices," Palmer said. "The answer was yes. Ten-month-olds can perceive the different performances and remember the ones they have heard before."

From a third experiment, Palmer and her colleagues found that prosodic features that do not match or reinforce the overall musical structure of a composition are the easiest to recognize when presented in the wrong musical context.

"For example, slowing down at the end of a musical phrase is more appropriate than slowing down in the middle of a phrase," Palmer said. When prosody does not fit musical structure, Palmer said, listeners are sensitive to the mismatch between the musical structure and the prosody.

"Memory for prosodic cues may be useful in music and speech because it helps listeners find important units in a continuous stream of sound," Palmer said. "Our experiments suggest that listeners may come equipped with this kind of episodic memory -- no extensive musical training or experience is necessary."

The overall findings of the study show that people remember music in the same way that they remember speech, in which characteristics of tone and inflection distinguish any two speakers. The overlap, Palmer said, could lead to a better understanding of the complexities of human memory.

The research was supported by grants from the National Institute of Mental Health and the National Institute of Child Health and Human Development.

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Pre-surgery factors affect satisfaction with eye surgery

Nearly a quarter to a third of patients that underwent LASIK surgery reported problems seeing at night, a new study suggests. Even so, 97 percent of the subjects said they would recommend LASIK to a friend.

Scientists at Ohio State analyzed data from 605 patients who had undergone LASIK (laser-assisted in-situ keratomileusis) surgery at least six months earlier. Reported vision problems included seeing halos, starbursts and glare surrounding lights -- problems that can affect the quality of vision at night.

The study showed that these symptoms may persist in some patients long after the eye heals. Such symptoms seemed to be linked to having had the surgery repeated, said Melissa Bailey, a study co-author and a postdoctoral fellow in vision.

"Patients who had undergone the procedure again were generally less happy with the outcomes than those who had the surgery only once, although we're unsure why," she said.

More than a million nearsighted Americans elected to undergo LASIK surgery last year in hopes of correcting their eyesight. But the researchers say that older patients, those with flatter corneas and those who needed to have the surgery redone were less likely to be happy with the results.

www.osu.edu/researchnews/archive/lasik.htm