Where Is the Brain’s One-Second Clock Switch?
Two experiments tested whether short and longer intervals use separate mental clocks. The apparent dividing line was less convincing than a subtler bias toward the middle.
The Invisible Clock
A fraction of a second can feel different from two full seconds. Does the brain switch timing machinery when the interval gets longer? That boundary is harder to find than it sounds.
In a 2025 study in Cognition, Renata Sadibolova and colleagues asked people to reproduce presented durations in two online experiments. One tested intervals from 400 to 2,400 milliseconds; the other narrowed the range to 1,000 to 2,000 milliseconds. Each experiment included 302 participants.
What the Tests Found
The team compared patterns across participants using factor analysis and structural-equation models, then searched individual responses for change points. Both experiments supported a general timing factor spanning the tested intervals and a second factor tied to central tendency: reproduced durations tend to drift toward the middle of the presented range.
- The question: do subsecond and longer intervals expose separate timing systems?
- The result: few individual change points were detected, offering limited support for a sharp split.
- The complication: a person's bias toward the middle can alter the pattern researchers might otherwise call a timing boundary.
A clock can divide seconds neatly. A judgment of seconds may not.
The Hidden Construct
A stopwatch measures elapsed time. The participant must remember and reproduce an interval, which adds perception, memory and response strategy to the measurement. The authors argue that central-tendency bias needs accounting for before treating a change in performance as evidence of two clocks.
This does not prove the brain has only one timing mechanism; the models address these tasks and ranges, not every form of subjective time. JitterSnap's interpretation is narrower and stranger: some boundaries we draw through experience may come from the test and its expectations, not a seam in time itself.
The accompanying licensed photograph of a mechanical stopwatch is a conceptual illustration of timing, not apparatus from the study.