How your brain processes two of life's most fundamental dimensions
Imagine a world where time stretches and contracts, where numbers feel like physical landmarks in your mind, and simple arithmetic follows mysterious, invisible rules. This isn't science fiction—it's the hidden reality of how your brain processes two of life's most fundamental dimensions: time and number. Every time you glance at a clock, estimate a crowd size, or sense how long until your coffee is ready, you're tapping into sophisticated neural systems that shape your reality in ways scientists are only beginning to understand.
Today, 1 is revealing that these two seemingly separate domains are deeply intertwined in the brain's architecture. From the 2 shared by humans and animals to the mysterious flexibility of subjective time, researchers are discovering that our experiences of duration and quantity share common neural pathways and cognitive resources.
Time and number processing overlap in brain regions like the parietal cortex
Psychological time frequently diverges from clock time based on context
What if you could estimate quantities without counting? This intuitive ability, called the "number sense," is increasingly recognized as a fundamental biological capacity shared across species 2 .
This number sense appears to be innate rather than learned. As Lorenzi and colleagues argue in their comprehensive analysis, the number sense is fundamentally present from birth in numerically competent animals, including humans 6 .
While we often think of time as a steady, universal constant, our brains tell a different story. Psychological time frequently diverges from clock time, stretching and compressing based on our experiences and mental states .
Recent research has revealed that the brain's alpha rhythm—once considered a potential internal metronome—isn't constant enough to serve as a reliable timekeeper . Instead, scientists now propose that the brain may have a GPS-like system for time similar to our spatial navigation system.
"An hour spent in a dentist's waiting room will seem much longer than an hour spent on a first date" — Virginie van Wassenhove, director of the CHRONOLOGY project
Researchers designed a clever experiment comparing time perception across different physical and mental conditions 1 . Participants estimated stimulus durations while:
This design allowed researchers to disentangle effects of physiological stress from cognitive demands of motor control.
The findings were striking. Participants consistently overestimated stimulus durations by approximately 7-9% in all three non-baseline conditions compared to standing still 1 .
Even more intriguingly, this distortion occurred across both sub-second and supra-second intervals, indicating that the effect taps into a general mechanism of time perception regardless of the time scale 1 .
| Activity | Physical Demand | Cognitive Demand | Time Estimation Bias |
|---|---|---|---|
| Standing still | Low | Low | Baseline (neutral) |
| Running on treadmill | High | High | +7-9% overestimation |
| Walking backward | Moderate | High | +7-9% overestimation |
| Mental task while standing | Low | High | +7-9% overestimation |
Some scientists propose that all numbers are translated and stored in a central "approximation area" in the brain—specifically the Horizontal Intraparietal Sulcus 9 .
According to this view, whether we see a digit "7," read the word "seven," or hear the spoken word, our brain converts all these formats into an approximate sense stored in the same neural territory.
Challenging evidence comes from research showing that memory retrieval times differ significantly depending on how numbers are presented 9 .
Participants were much faster at retrieving numbers from memory when they had first been shown as digits compared to written number words. This suggests that numbers may not all be translated into a central number sense area but rather remain stored in format-specific regions.
Measures brain activity by detecting changes in blood flow
Identifying brain regions active during arithmetic tasksRecords electrical activity of the brain
Studying brain rhythms involved in time perceptionMaps brain activity by measuring magnetic fields
Tracking the brain's processing of temporal informationAssess performance through controlled activities
Testing time estimation during physical activitiesMeasures activity of individual neurons
Studying neural mechanisms in animalsSimulates neural circuit architecture
Modeling how brain circuits represent timeThe Gordian knot connecting time and number in the brain is far from completely untied, but neuroscience has made remarkable progress in revealing its intricate twists and turns. We now know that our experiences of time and number are not solitary phenomena but deeply interconnected processes sharing cognitive resources and neural real estate.
The cognitive demands of controlling movement can warp our sense of time, while the order of numbers in simple arithmetic can significantly impact the mental effort required.
What emerges from these insights is a more embodied view of mathematics and time perception—both are deeply connected to our physical experiences and movements.
Time and number share cognitive resources and neural pathways in the brain
Projects like CHRONOLOGY bring together mouse, primate, and human studies
Understanding implications for education, rehabilitation, and AI
"The brain is the most complex system in the universe, even more complex than a star or a black hole—a star and black hole that it is itself capable of conceiving! We still have almost everything to learn about how it works" — Virginie van Wassenhove