It happens to everyone: A familiar song comes on the radio, and suddenly you recall every note and every word.
Now, new research has pinpointed exactly how long it takes people to recognise that favourite tune – just 0.1 to 0.3 seconds.
Song recognition revealed by pupil dilation
The study included five men and five women who each provided a list of five familiar songs that they associated with good memories.
The researchers then chose one of each participants' songs and matched it with a song that was similar in tempo, melody, harmony, vocals and instrumentation, but was unfamiliar to the participant.
Each participant was randomly played 100 snippets (each less than a second) of both the familiar and unfamiliar song. The researchers monitored the participants' electrical activity in the brain and their pupil diameter (a measure of arousal) while they listed to the song snippets.
Song recognition was first revealed by pupil dilation likely associated with increased arousal triggered by the familiar song, followed by brain activity related to memory retrieval, according to the study published online in the journal Scientific Reports.
A "control group" of people unfamiliar with any of the songs used in the study had no differences in responses to any of the songs, said the researchers at the University College London Ear Institute.
"Our results demonstrate that recognition of familiar music happens remarkably quickly," study senior author Maria Chait said in a school news release.
"These findings point to very fast temporal circuitry and are consistent with the deep hold that highly familiar pieces of music have on our memory," Chait added.
"Beyond basic science, understanding how the brain recognises familiar tunes is useful for various music-based therapeutic interventions," she said.
"For instance, there is a growing interest in exploiting music to break through to dementia patients for whom memory of music appears well-preserved despite an otherwise systemic failure of memory systems," Chait explained.
"Pinpointing the neural pathway and processes which support music identification may provide a clue to understanding the basis of this phenomenon," Chait concluded.
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