The rules
How to play: guess the seconds
Watch the two bars: the first signal starts the time, the second one ends it.
To your guess, then fine-tune it with − and +.
Every try uses a different time between 0.30 and 10 s.
Why do we misjudge short and long times?
Timing research covers intervals from a few milliseconds to several seconds (Grondin, 2010), and the size of the bias depends on the task and the person.
How accurate is human time estimation?
It depends on the interval and the task. In Lewis & Miall’s experiments, trained participants’ largest average errors were an overestimate of 44% on short intervals and an underestimate of 19% on long ones, across intervals from 215 ms to 3.59 min (Lewis & Miall, 2009). These are the largest errors in that range, not typical errors for 0.30 to 10 s.
Mean overestimate of about 500%
Lewis & Miall, 2009Mean underestimate of about 35%
Lewis & Miall, 2009Largest mean errors: +44% on short, −19% on long
Lewis & Miall, 2009Weber’s law best described sensitivity to changes in duration
Haigh et al., 2021Figures are the paper’s extremes across the ranges shown, not errors at 10 s. Weber’s law: the smallest difference you notice grows in proportion to the duration.
Tips to guess the seconds better
Count from the first signal; don’t wait to “feel” the gap.
Start a steady count the moment the first bar lights up.
Drag close, then fix the hundredths.
FAQ
How accurate is human time estimation?
It depends on the interval and task. In Lewis & Miall (2009) trained participants’ largest average errors in two production experiments were an overestimate of 44% on short intervals and an underestimate of 19% on long ones (intervals from 215 ms to 3.59 min) (Lewis & Miall, 2009).
Why do short gaps feel longer and long ones shorter?
It is the “central tendency” effect: people tend to overestimate short intervals and underestimate long ones (Lewis & Miall, 2009).
Does the error grow with longer intervals?
Not in a simple way: Haigh et al. (2021) found Weber’s law described sensitivity to duration changes best for 100-3200 ms (Haigh et al., 2021), and Lewis & Miall (2009) found relative variability falling slowly with length (Lewis & Miall, 2009).
Is this a clinical test?
No. It is a playful check of your sense of time, not a diagnostic tool.