SART Test — Free 225-Trial Mind-Wandering and Sustained Attention Task

The SART was developed in 1997 by Robertson and colleagues to capture everyday attentional slips. The rule is very simple, but the stimuli come fast enough that your hand starts moving automatically — and if your mind is elsewhere at that moment, you miss the one time you should stop. It catches mind-wandering not by being hard, but by being easy enough to let your guard down.

Digits from 1 to 9 appear one at a time for 0.25 seconds, spaced 1.15 seconds apart. Tap as soon as a digit appears, but hold back when it is a 3. Each digit appears 25 times for 225 trials in all, so there are 25 trials where you must withhold. The digit size changes randomly across five levels so you cannot rely on its shape, and the run is split into five blocks to track changes over time.

Pressing on a 3 (a commission error) marks a moment when attention left the task, so it serves as an index of how often the mind wanders. A pattern of speeding up just before an error signals that the hand has slipped into automatic mode.

The headline focus score is the proportion of 3s you successfully withheld on: the number of presses among the 25 threes is subtracted and converted to a percentage, so 0 commissions gives 100 and 5 gives 80. The app explains results in four bands — up to 2, up to 5, up to 10, and more than 10 commissions — and separately lists omissions, where a digit appeared but you did not press.

The coefficient of variation (CV) of reaction time is the standard deviation divided by the mean: under 15% is described as steady, under 25% as moderate, and higher as erratic. The reaction-time slope across the five blocks counts as late-block slowing if it exceeds 8 ms per block, as automatic speeding if it falls by more than 8 ms per block, and as a steady flow in between. If the mean reaction time on the four trials before each commission is more than 30 ms faster than your overall mean, pre-error speeding is judged pronounced.

Since each digit shows for only 0.25 seconds at 1.15-second intervals, responses faster than 0.1 seconds are counted separately as anticipations. Device latency adds about equally to every trial and so barely affects variability or slope, but the first attempt or two carry a practice effect as the rule settles in, so watch the trend across repeated measurements.

Mind-wandering increases most when you are drowsy. On short-sleep days, right after lunch and late at night, commissions and variability rise together; caffeine speeds responses but can egg on the automatic hand and add presses on 3s. Notifications or nearby noise during the test translate directly into slips at that moment, so try it in a quiet setting with do-not-disturb on.

Soundary saves your results and shows the change from your previous test. Repeating every one to two weeks at a similar time of day on the same device, and following the trend in commission count and CV, helps you tell condition-related fluctuation from steady change. This is a self-check, not a diagnostic tool.

If results with more than 10 commissions keep recurring even when you are well rested and in a quiet setting, and in daily life you often drift into other thoughts during conversations or reading in ways that cause trouble, consider discussing an attention assessment with a psychiatrist or other professional. If sleep problems or mood changes are also present, it helps to look at those together.