Trail Making

Targets are scattered across the screen, and you connect them in the correct sequence without lifting your attention. In Part A you link numbers in order: 1, 2, 3, and so on. In Part B you alternate between numbers and letters: 1, A, 2, B, 3, C, and up. Your score is the time to complete each part, so faster is better, with errors typically corrected on the spot and costing you time.

Part A leans on visual search and processing speed: your eyes hunt for the next target while your hand moves. Part B keeps all of that and adds set-shifting, the executive-function skill of switching back and forth between two rules. Because you must constantly change tracks between the number line and the alphabet, Part B is reliably slower than Part A.

This is a digital take on the Trail Making Test, Parts A and B, a task widely associated with Ralph Reitan, who popularized it as part of a broader neuropsychological battery in the mid-twentieth century. It has been used for decades precisely because it is quick, simple to administer, and sensitive to how efficiently someone can search a display and switch between rules.

The two-part design is what makes it useful. Part A gives a baseline for pure speed and scanning. Part B layers on the extra demand of alternation. Because Part A and Part B share the visual-search component, the difference between your two times isolates the added cost of switching. That B-minus-A gap is often more informative than either raw time by itself.

Times vary widely with age, the layout, and your device, so treat specific numbers as loose context rather than a standard. The dependable pattern is the relationship between the parts, not the exact seconds:

• Part A: the faster part, since you follow a single ascending sequence.
• Part B: reliably slower, because alternating between numbers and letters adds switching cost on every step.
• The gap: the extra time Part B takes over Part A reflects the price of set-shifting.

Processing speed peaks in young adulthood and slows gently with age, so completion times tend to rise across the decades while the overall pattern holds. A large gap between B and A is common and expected; the parts are designed so that switching is meant to be harder than straight sequencing.

You can shave time off both parts with practice, mostly by scanning more efficiently and locking in the alternation rhythm on Part B. Be honest, though: the improvement is largely specific to this task, and a chunk of it is simple familiarity with the layout style rather than a broad gain in speed or flexibility.

• Look ahead. While your hand moves to the current target, let your eyes already hunt for the next one.
• Chant the pattern on Part B. Keeping a rhythm like "one-A, two-B" reduces switch errors.
• Do not sacrifice accuracy for speed. A wrong connection you have to correct costs more time than moving carefully.
• Expect a warm-up and regression to the mean. Your first attempt usually understates you, and one unusually fast run may not repeat.

One caveat on interpretation: this is a self-testing tool, not a clinical or diagnostic instrument. Slow times can come from an unfamiliar layout, a small screen, a trackpad, or plain tiredness. Read your result as a snapshot, and compare yourself against your own previous runs rather than against strangers on different hardware.

Several conditions move your times, so read any single run as approximate. The size and spread of the targets, your pointing device, and your focus all matter. A cramped layout on a phone makes both parts slower than a roomy layout on a large screen.

• Switch errors on Part B: grabbing the next number when you owed a letter, or the reverse, is the classic slip and it eats time.
• Overshooting targets: a jittery mouse or trackpad forces re-tries that inflate the clock.
• Scanning too narrowly: staring only near the current target means you waste time hunting for the next one.
• Practice effects: your times drop over the first few attempts as the format becomes familiar.
• Fatigue and distraction: processing speed sags when you are tired, so late runs can look worse.