Humans' memory of sound is weaker than for other stimuli

"As it turns out, there is merit to the Chinese proverb 'I hear, and I forget; I see, and I remember,'" says graduate student James Bigelow.

Bigelow and his University of Iowa (UI) colleagues have published their results of an investigation into how humans remember sound in the journal PLOS One.

Their findings? That we have a harder time remembering things we have heard, compared with things we have seen or felt.

"We tend to think that the parts of our brain wired for memory are integrated," says Amy Poremba, associate professor in the UI Department of Psychology and corresponding author on the paper.

Prof. Poremba says the team's findings may indicate that the brain uses separate pathways to process information:

"Even more, our study suggests the brain may process auditory information differently than visual and tactile information, and alternative strategies - such as increased mental repetition - may be needed when trying to improve memory."

Testing short-term and recognition memory

The UI team designed an experiment to test the short-term memory of more than 100 participating UI undergraduates.

The students were asked to wear headphones and listen to pure tones, to look at various shades of red squares, and to feel low-intensity vibrations by gripping an aluminum bar. Time delays between 1 and 32 seconds separated each set of tones, squares and vibrations.

Though participants were worse at recalling the sounds they had heard, their memory of the things they had seen or felt was about the same.

The researchers found that the students' memory of sounds declined much faster than their memory of the squares and the vibrations.

A second experiment tested the recognition memory of the participants. They listened to sound recordings of dogs barking, watched silent videos of a basketball game and felt common objects - such as a coffee mug - that they were unable to see.

The researchers found that between an hour and a week after the experiment, students were worse at recalling the sounds they had heard, but that their memory of the things they had seen or felt was about the same.

The implication from both studies is that the brain processes and stores sound differently to how it processes other memories.

"As teachers, we want to assume students will remember everything we say. But if you really want something to be memorable you may need to include a visual or hands-on experience, in addition to auditory information," says Poremba.

Primate brains have a shared weakness for recalling audio

Although some previous studies have suggested that humans are better at remembering visual information than audio information, Bigelow and Poremba's study is the first to show that our memory of touch is roughly equal to our memory of what we see.

They think this is significant, as similar experiments with monkeys and chimpanzees have demonstrated that they perform equally well in visual and tactile memory tasks, but - like humans, their less-hairy primate relatives - they struggle more with auditory memory tasks.

Consequently, the researchers believe that this shared relative weakness for auditory memory has its origins in the neurological evolution of primates.