The world's clocks mark every passing second, minute and hour. But to humans, seconds of pain can feel like minutes, and hours spent at a party can end in a blink.
The brain can stretch or squeeze the feeling of time for many reasons, including pleasure, pain, fear and age. Although the science behind this "subjective time" is not fully understood, some research suggests that an additional factor might influence the subjective length of your life: your income.
Research already suggests that, on average, wealthy people live longer, biologically. Now, emerging work indicates that varied and novel experiences could create more "time codes" in the human brain as it processes memory formation. This, in turn, could mean that people who can afford to enjoy more vacations and hobbies, and who have more stimulating jobs, will recall having lived for a longer time on Earth.
"Even though time flies when you're having fun, when you look back on it, you can remember much more of this extended experience compared to a boring experience," says Jorgen Sugar, a postdoctoral student at the Norwegian University of Science and Technology's Kavli Institute for Systems Neuroscience. He's part of a team of scientists investigating these mental time codes.
The idea that novelty can affect the experience of time also seems to fit cultures that don't measure time using clocks—many cultures rely instead on celestial (天空的), cultural and seasonal events to mark the flow of time. "Our experience of time does vary according to circumstances, and also according to the kind of rhythm of activity we engage in," says Chris Sinha, a cognitive scientist working with Hunan University who has studied so called "event-based time" in Amazonian tribes and linguistic minority groups in China.
But other experts aren't convinced. According to Monica Capri, an economist with a background in neuro-economies at Claremont Graduate University, subjective time isn't well understood scientifically. Even if higher-paid jobs can lead to more new experiences, wealthy people aren't necessarily spending money that way. A millionaire, for instance, may spend money on a fancy watch, but this isn't likely to change their feeling of time the way a vacation or even a low-cost hike would, she says.
What's more, she says, there are many factors to consider in how the brain processes time. For instance, according to Adrian Bejan, a professor at Duke University, the novelty of fun experiences can simply wear off.
Still, researchers from many fields are eager to uncover the mysteries of memory and subjective time. According to Sugar, understanding how humans form and recall memories can affect many aspects of society, such as law, education and health care—and perhaps can even aid our understanding of ourselves. "The human brain is the most complex biological system we know," he says.
