Trail Making
1→A→2→B→3 — attention switching
About this trainer
Trail Making is a connect-the-dots speed task. The screen shows scattered circles and you tap them in the right order as fast as you can without lifting your focus: in the simple version that is numbers 1-2-3 up to the last one, and in the harder version you alternate between numbers and letters, 1-A-2-B-3-C, switching tracks on every step.
What it develops
It trains visual scanning and processing speed in the number-only version, and on top of that cognitive flexibility, the ability to switch between two rules without losing your place, in the number-letter version. That set-switching demand is what makes the alternating mode a classic window onto executive function.
History
It grew out of Partington's Pathways Test from 1938, a simple paper task. In 1944 it was folded into the U.S. Army Individual Test Battery and got the name Trail Making Test, and in the 1950s the neuropsychologist Ralph Reitan adopted it for brain-injury screening and built it into the Halstead-Reitan battery, which made his paper-and-pencil version the one most clinics still use today.
Who created it — and when
There is no single modern inventor. The first version is credited to the American psychologist John E. Partington around 1938 (published as Partington & Leiter, 1949); the number-letter format and the name came from the U.S. Army in 1944, and Ralph Reitan standardized and popularized it from the 1950s onward.
How to train
Sweep your eyes ahead to locate the next two or three targets before you tap, rather than hunting one at a time. In the alternating mode keep two pointers in mind at once, the next number and the next letter, so the switch costs you less. Accuracy first, then speed, since a wrong tap usually costs more time than moving a touch slower.
How long to practise
Short sessions work best: a handful of boards over five to ten minutes, a few times a week. Because gains plateau quickly and it is more of a sprint than an endurance task, brief frequent practice beats long grinding sessions.
Evidence base
What is solidly shown is exactly what you would expect: with practice you get faster and more accurate at trail making itself, and the task is a well-validated clinical measure of processing speed and set-switching. The leap from there to broader gains is where the evidence is weak. Large meta-analyses of cognitive training find that transfer to untrained abilities or general intelligence shrinks toward zero once studies use proper active control groups, so treat any promise that it makes you smarter overall or wards off decline with caution.
Recommendations
Use the number-letter mode as your main challenge, since the rule-switching is where the real workout is, and keep the runs short.
FAQ
What is the difference between the numbers-only and the number-letter mode?
The numbers-only mode mostly tests how fast you can scan and sequence. The number-letter mode adds constant rule-switching between two sequences, which loads cognitive flexibility, and that is why it normally takes people about twice as long.
What counts as a good time?
For healthy adults the numbers-only part averages around 30 seconds and the alternating part around 75 seconds, but these depend heavily on age and the exact layout, so compare yourself to your own past runs rather than to a fixed number.
Will this make me smarter or faster in everyday life?
Honestly, not in any broad way that research backs. You will clearly get better at this task and at similar scanning and switching, but the controlled evidence for transfer to general intelligence or daily functioning is weak, so enjoy it as focused practice, not a brain upgrade.
Variants
Variants change the targets and the channel: number-only (Part A) versus alternating number-letter (Part B); color-based versions that switch between two colors instead of letters; shape or zodiac versions for non-Latin alphabets; oral and walking versions that drop the hand entirely; and longer grids that simply add more circles.