Hidden Rule Discovery — Free Rule Inference & Cognitive Flexibility Test

This task looks at your ability to discover a hidden rule from nothing but right/wrong feedback, and then to drop the old habit and adopt a new rule when it changes. Four reference piles sit at the top: one purple square, two sky-blue hexagons, three orange diamonds and four pink half-moons. You place each card that appears below onto a pile by color, shape or number, and you are told at once whether it was correct.

The rule is one of three, color, shape or number, and after 8 consecutive correct answers it changes to another rule without warning. From that moment the approach that was just working starts failing, and how quickly you notice and change strategy is the crux. The format derives from the card-sorting paradigm proposed by Grant and Berg (1948).

Soundary's version is built in-house from the published paradigm rather than being any commercial test form, and it deliberately uses different colors and shapes from the original stimuli. The three rules cycle up to 6 times within 96 cards, and the results cannot be compared directly with commercial norm tables.

The headline metric is the number of rules completed, that is, how many rules (up to 6) you reached 8 consecutive correct on. Completing all 6 indicates very smooth rule switching; 3 to 5 is described as a broadly stable range for finding and changing rules; fewer than 3 suggests possible difficulty switching. If fewer than 12 cards were sorted, no interpretation is given.

Failure to maintain set counts the times you got 3 or more correct in a row yet made an error before reaching 8; it captures lapses of attention or forgetting the rule after you had found it. The perseveration tendency shown alongside is the proportion of cards you kept sorting by the old rule after it changed: under 10% low, under 20% medium, 20% or more high.

Also reported are accuracy (%), cards used, mean cards per rule and mean response speed; the score stored is accuracy. Getting a few cards wrong right after a rule change is inevitable because there is no way to know the new rule, so those errors are not a deficit. A first attempt starts without knowing there are three kinds of rule, so scores tend to rise from the second session through practice.

Strategy and sustained attention matter more here than speed, so fatigue, sleep loss and a distracting environment increase failures to maintain set. Knowing even once that there are three rules changes the outcome, which makes practice effects larger than in most cognitive tasks. People with color-vision differences may be at a disadvantage on the color rule; in that case read the result mainly through the shape and number rules.

Rule-switching ability develops through childhood and tends to weaken gradually in later life. If your perseveration came out high, first consider recent stress and sleep, then try again about a month later. Given the practice effect, a retest interval of at least 4 weeks is recommended.

This is a self-check, not a diagnostic tool. Still, if you repeatedly complete fewer than 3 rules or your perseveration stays at 20% or more even on good days, and changing how you do things feels unusually hard in daily life, consider having executive function looked at with a professional in a psychiatric or neuropsychological evaluation.