Study links approaching background sounds to longer time estimates
Researchers in Japan found that sounds seeming to move closer made listeners judge separate tones as lasting longer.
By Priya Raghavan · Science Reporter
3 min read
Sounds that seem to be coming closer can make people think a separate sound lasted longer, according to a study published in Scientific Reports. The finding matters because it suggests the brain’s timing judgments can shift even when moving noise is only in the background.
The paper, by Achille Pasqualotto and colleagues, examined whether motion cues in sound affect how people estimate time while they are focused on another auditory signal. Phys.org reported that earlier work had tied approaching sounds to expanded time perception, but the new study tested the effect when the moving sound was not the target of attention.
How the experiment worked
The researchers recruited 48 college students and divided them into three groups, according to Phys.org. Participants were blindfolded and used headphones, limiting the task to what they heard.
One group heard background audio that appeared to move toward them. A second group heard sounds that appeared to move away, and a third heard scrambled sounds. Phys.org reported that the background sounds were produced with vOICe, software that turns images into audio.
At the same time, each participant heard foreground sine-wave tones of different lengths. The volunteers were told to judge only the duration of those foreground tones, not the background audio.
After each tone ended, participants pressed and held a computer spacebar for the amount of time they believed the tone had lasted. The research team then used statistical analysis and a mathematical model to compare how the different background sounds affected those estimates, according to Phys.org.
Approaching sound changed estimates
Listeners exposed to approaching background sounds overestimated the foreground tones by about 15%, Phys.org reported. The study authors said the approaching background audio produced a significantly faster subjective sense of elapsed time compared with receding sound.
The group hearing receding background noise underestimated duration by about 6%, according to the report. Results from the scrambled-sound group fell between the other two groups, but Phys.org said the differences between that group and the others were not statistically significant.
The researchers said the study was the first to show that moving background sounds can alter time estimates. Their conclusion points to a broad role for environmental audio cues in perception, even when people are concentrating on another sound.
A possible alert response
The team interpreted the results through an evolutionary lens, according to Phys.org. They proposed that a sound moving closer may put the brain on alert, preparing a person to avoid or intercept an approaching object.
By contrast, the researchers said a sound moving away may demand less attention because it is less likely to signal a threat. That reduced urgency could help explain why participants in the receding-sound group judged tones as shorter than they were.
The experiment also showed the Vierordt effect, a known bias in time perception, Phys.org reported. Participants tended to judge the shortest tones, lasting 1 second, as longer than their actual duration, while they judged the longest tones, lasting 6 seconds, as shorter.
The study, titled “Approaching background sounds extend the duration of foreground auditory stimuli,” was published in 2026 in Scientific Reports. Phys.org reported the paper and identified the work as peer-reviewed.
This story draws on original reporting from Phys.org.