Double Decision is the best-known exercise in BrainHQ's programme: identify a vehicle in the centre of the screen while simultaneously locating a target in your peripheral vision, with both shown for a shrinking fraction of a second. It is a divided-attention task built around what researchers call the useful field of view. This is what it trains, what the evidence actually says, and the free games here that load the same thing.
Your useful field of view is the area from which you can take in visual information in a single glance without moving your eyes. It is considerably smaller than your total visual field, and it shrinks under load, under time pressure and with age.
That shrinkage has practical consequences. A driver with a narrow useful field of view has to make more eye movements to cover the same scene, and each movement is time during which the rest of the scene is unmonitored.
Why the task has two halves
A central identification task alone measures foveal processing. A peripheral localisation task alone measures how far out you can detect. Doing both at once is what makes it a field-of-view measure rather than either one — you cannot solve it by moving your eyes, because moving them loses the central target.
Useful-field-of-view training is among the more studied forms of cognitive training, and it has produced some of the most-cited and most-argued-about results in the area.
The large ACTIVE trial in older adults included a speed-of-processing arm built on this kind of task. It reported durable improvements on the trained measures and, in later analyses, associations with outcomes including driving and everyday function. Those findings are real and they are also contested: independent replication has been patchy, several of the follow-up claims rest on secondary analyses, and the commercial claims made on the back of them have gone considerably further than the data.
The defensible summary is that this specific kind of training reliably improves the specific ability it trains, that the useful field of view is a meaningful ability with real-world relevance, and that everything beyond those two statements deserves scepticism.
None of these is Double Decision, and none of them is a substitute for a clinical or commercial programme. They load overlapping abilities and they are free.
Dual Tracker — track two targets in separate zones at once, which is the closest analogue here: you cannot cover both with a single gaze.
Drive Safe — steer between lanes while answering arithmetic below the road, a divided-attention task with a driving skin.
Eagle Eye — peripheral visual search, the locating half of the task.
Blink Test — central identification at shrinking display durations, the identifying half.
Motion Detector — peripheral motion detection, which is what peripheral vision is genuinely good at.
Traffic Control — routing several moving objects, where scanning discipline replaces genuine tracking.
The multitasking hub and the tracking hub collect the rest.
Widen your gaze rather than flicking
The instinct is to look at each thing in turn. That defeats the task, because the point is what you can take in without moving your eyes. Soften your focus on the centre and let the periphery report.
Trust the periphery for motion
Peripheral vision resolves detail poorly and detects movement well — the retina's periphery is dominated by cells that respond to change. Looking slightly away from where you expect movement often detects it sooner.
Decide in advance what you will drop
Under real load you will lose one of the two tasks. Deciding which in advance, and dropping it cleanly, scores better than degrading both. This is what separates good scores from bad ones on every task in the multitasking hub.
Accept that you are switching, not parallelising
For two tasks that both need attention, people alternate rather than genuinely working in parallel, and each switch costs time. What improves with practice is the speed of the switch, or making one task automatic enough to need no attention at all.
BrainHQ's best-known exercise: identify a vehicle in the centre of the screen while locating a peripheral target, both shown briefly. It is built around the useful field of view.
Not an identical one here. Dual Tracker and Drive Safe load the same divided attention and are free, with no account and nothing to install.
It reliably improves the ability it trains. Claims about transfer to driving and everyday function come largely from the ACTIVE trial and later analyses, which are genuinely debated and have had patchy independent replication.
The area you can take information from in a single glance without moving your eyes. It is smaller than your full visual field and it shrinks under load and with age.
For two tasks that both need attention, essentially no — we alternate, and each switch costs time. What improves is switch speed, or making one task automatic.
The useful field of view is a real ability worth practising, and the evidence for what training it transfers to is weaker than the marketing suggests. Widen your gaze, decide in advance what you will drop, and start with [Dual Tracker](/games/dual-tracker).