Our Experience of Time Changes When Certain Brain Cells Get Tired, Scientists Believe

How neurons in the brain react to stimuli may explain why our perception of time is subjective, according to a study.

The study published in JNeurosci involved 18 healthy volunteers, 11 males and 7 females, whom the researchers sent through fMRI scanners to investigate their perception of time. In the scanner, the participants were shown a grey circle 30 times in a row. Next, they were presented with a visual stimulus, a grey cross, of different lengths, or auditory stimulus of white nose of a fixed length, and were asked how long they lasted. There were three scenarios in total, each tested in separate runs of the scan. The team looked at localized blood oxygenation levels in the brains of the participants and compared them with their reports of their experiences in the scanner.

The team found that activity in a part of the brain known as the supramarginal gyrus "reflects [the] subjective experience of time."

When the circle and the cross or the sound were presented for similar periods of time, the activity of neurons in the supramarginal gyrus reduced. The more the activity in this area lessened, the more the participants' perception of time was skewed. This suggested the neurons were becoming tired.

The authors wrote the findings are consistent with the hypothesis that our subjective experience of time is represented by the activity in the right area of the supramarginal gyrus.

More research is needed to test the causal relationship between how we perceive time and the supramarginal gyrus, they said.

Co-author Masamichi Hayashi, researcher at the Center for Information and Neural Networks at Japan's National Institute of Information and Communications Technology and the Department of Psychology at the University of California, Berkeley, told Newsweek: "Since our study explored the neural basis of subjective time perception in the range of hundreds of milliseconds, it is still an open question if our findings can be generalized to the perception of longer time ranges such as minutes, hours, days, weeks, and years.

"Exploring the neural mechanism of perceiving such very long time intervals is an interesting direction of future research."

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A stock image shows a clock against a blue and orange background. Scientists have investigated how we perceive time.

Warrick Roseboom, a lecturer in Cognitive Science at the University of Sussex who did not work on the study, told Newsweek he found the work "interesting" and that it builds on our basic understanding of how the team's methods can be used.

However, he said the team's hypothesis was dated. Roseboom also said: "I think extending the interpretation to daily life is too far" and said he was not sure how the method, showing participants a blob repeatedly, could correspond with "the scale of diverse experience we have over a day."

Roseboom said a distinction should be made between the way time is experienced when being explicitly asked to pay attention and report on it, as in the study, versus when a person is not paying attention to time and then think back in retrospect.

He said our experience of time throughout a day is built of different combinations of experiences, such as waiting intently for a bus and watching the time, working on some engrossing problem or spending some enjoyable time with friends and family.

Earlier this year, a separate team of scientists published a study on our perception of time, which took a different approach. They found that outbound trips feel longer than the same inbound trips because of the sense of anticipation of the initial journey. They published their study "Are We There Yet? An Anticipation Account of the Return Trip Effect," in the journal Social Psychological and Personality Science.