The question is transfer, not improvement
Nobody disputes that practising a cognitive task improves performance on that task. Do a digit span drill every day and your digit span goes up. The interesting claim is different: that the improvement spreads to abilities you did not train — memory in daily life, attention at work, resistance to cognitive decline. Researchers call this transfer, and they distinguish near transfer (to closely similar tasks) from far transfer (to genuinely different abilities and to everyday functioning).
Near transfer is real but modest. Far transfer is where the commercial claims live, and where the evidence is thinnest. Almost every disagreement about brain training reduces to somebody presenting near transfer as though it were far transfer.
The large trials
The most striking test of scale came from a study run with the BBC. Owen and colleagues (2010) put 11,430 participants through six weeks of online brain training and compared them with a control group who spent equivalent time answering general knowledge questions using the internet. The trained groups improved on the training tasks. On untrained cognitive tests, the authors reported no evidence of transfer, even to tasks that were closely related to those trained.
The most comprehensive review is Simons and colleagues (2016), an examination of the brain-training literature published in Psychological Science in the Public Interest. Their conclusion was that the field showed extensive evidence for improvement on trained tasks, less evidence for near transfer, and little convincing evidence that training improves everyday cognitive performance. They were also pointed about study quality: many positive results came from small samples, weak control conditions, and outcome measures that resembled the training.
The control-group problem deserves its own sentence. If your control group does nothing while your training group logs in daily to a colourful app that congratulates them, some of the resulting difference is expectation and motivation rather than cognition. Studies with active control groups — people doing an equally engaging but different activity — consistently show smaller effects than studies with passive controls.
Where the picture is more favourable
Two qualifications keep this from being a flat dismissal.
First, specific, narrow training with a specific target sometimes does hold up. The ACTIVE trial, a large randomised study of cognitive training in older adults reported by Ball and colleagues (2002), found that training produced improvements in the trained abilities that were still detectable two years later. What has been argued about ever since is how far those gains extended into everyday activities, and by how much.
Second, "no far transfer" is not the same as "no value". Training your working memory to be better at a working memory game is a real skill gain, in the same way that getting better at a musical instrument is real even though it does not make you generally smarter. The failure is in the marketing claim, not in the activity.
And the things that do reliably support cognition are unglamorous and well evidenced: sleep, cardiovascular exercise, treating hearing loss, social engagement, managing blood pressure. They are harder to sell as an app.
Why this site measures rather than trains
This is a testing site, not a training programme, and the distinction is deliberate. We do not claim that repeating these tests will make you sharper, because we would not be able to support that claim. What repetition here will do is make you better at these tests, which is worth knowing when you interpret your own history: a large improvement over your first few runs is mostly you learning the task.
The same honesty governs the numbers. Where a published normative distribution plausibly matches what a test does, we show a percentile and link the study. Where it does not, we show your score and nothing else, because inventing a distribution is easy and would make the site look more authoritative exactly where it deserves less trust. Four of the six tests here have no percentile for that reason, and the methodology page says which and why.
If you want a benchmark, this is one. If you want cognitive improvement, the evidence points at your sleep schedule and your running shoes before it points at any screen, including this one.
How to read a brain training claim
A few questions that separate a real result from a press release:
- What was the control group doing? If they were doing nothing, expect the effect to shrink when compared against an active control.
- Does the outcome measure resemble the training? If the trained task and the tested task are near-twins, you are looking at near transfer being sold as far transfer.
- How many people, and were they randomly assigned? Small non-randomised studies produce large, unreliable effects.
- Did the benefit show up in daily life, or only on another test? This is the claim that matters and the one most often skipped.
- Who paid for it? Not disqualifying, but industry-funded trials of the funder's own product deserve a closer read.
Frequently asked questions
So brain training is a scam?
Not a scam, but generally oversold. The activities do what practice does: they make you better at what you practise. The problem arises when that is marketed as making you smarter, more focused at work, or protected against decline, because those are the claims the evidence does not support well.
Will practising these tests improve my scores?
Yes, and quickly at first. The early gains are mostly learning what each test wants — where to look, how to click, what strategy to use. Those gains flatten, and where they flatten is closer to your actual ability than your first attempt was.
Does anything reliably help cognition?
Sleep, aerobic exercise, treating hearing loss, staying socially engaged, and managing cardiovascular risk factors all have better evidence behind them than any commercial training program. None of them are as convenient as an app, which is a large part of why the app market exists.
Why do I keep seeing studies that say it works?
Because there are many of them, and they vary enormously in quality. Small trials with passive control groups and training-like outcome measures tend to produce positive results, and positive results get written about. The reviews that weigh studies by quality rather than counting them reach more cautious conclusions.
Is a testing site like this one useful at all?
As a mirror rather than a gym. Knowing your reaction time and how it moves with sleep, time of day and equipment is genuinely informative. Believing that clicking here three times a week is building your brain is not supported, and we would rather say so than sell it.