The question is transfer, not improvement
Nobody disputes that practising a mental task makes you better at that task. Do a digit span drill every day and your digit span goes up. The big claim is that the gain spreads to things you did not train, such as:
- memory in daily life
- focus at work
- protection against mental ageing
Researchers call this spreading transfer. Near transfer means gains on very similar tasks. Far transfer means gains on truly different skills, and in daily life.
Near transfer is real but modest. Far transfer is where the sales claims live, and where the evidence is thinnest. In our view, almost every argument about brain training comes down to somebody presenting near transfer as if it were far transfer.
The large trials
The largest early test was a study run with the BBC. Owen and colleagues (2010) had 11,430 people do six weeks of online brain training. A control group spent the same time using the internet to answer quiz questions. The trained groups improved on the training tasks. On untrained tests, though, the authors found no evidence of transfer, even to tasks closely related to the ones they trained.
The biggest review is Simons and colleagues (2016), a survey of the whole field published in Psychological Science in the Public Interest. They found plenty of proof that people get better at the trained tasks. They found less proof of near transfer, and little good proof that training helps everyday thinking.
They were blunt about study quality too. Many positive results came from small groups, weak comparisons, and tests that looked just like the training.
The control group matters a lot here. Say your control group does nothing, while your training group logs into a colorful app every day and gets praised by it. Part of the difference you see is then hope and motivation, not brainpower. Studies with active control groups (people doing an equally engaging but different activity) consistently show smaller effects than studies with passive ones.
Where the picture is more favorable
That does not make brain training worthless, for two reasons.
First, narrow training with a specific target sometimes does hold up. The ACTIVE trial, reported by Ball and colleagues (2002), was a large, careful study of brain training in older adults. The trained skills were still better two years later. People have argued ever since about how far those gains reached into everyday life, and by how much.
Second, no far transfer does not mean no value. Getting better at a memory game is a real skill, like getting better at an instrument. It is real progress, even though it does not make you smarter overall. The problem is the marketing claim, not the game.
The things that do reliably support thinking are plain and well tested:
- sleep
- cardiovascular exercise
- treating hearing loss
- social engagement
- managing blood pressure
They are just harder to sell as an app.
Why this site measures instead of training you
This is a testing site, not a training programme, and we chose that on purpose. We do not claim that repeating these tests will make you sharper, because we could not back that up. What practice here does do is make you better at these tests.
Keep that in mind when you read your own history. A big jump over your first few runs is mostly you learning how the test works.
The same honesty applies to the numbers. When a published study's distribution matches what a test does, measured the way you actually play it, we show a percentile and name the study. When the match is not honest, we show your score and nothing else, even if famous data exists. Reaction time, for example, cites a large lab study as reference but shows no percentile, because browser and device delay would quietly bend the comparison.
Making up a curve would be easy. We think it would also make the site look most trustworthy exactly where it deserves the least trust. The methodology page lists every source.
If you want a benchmark, this is one. If you want to think better, 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
These questions help separate a real result from a press release:
- What was the control group doing? If they did nothing, expect the effect to shrink against an active control.
- Does the test look like the training? If the trained task and the tested task are near twins, that is near transfer being sold as far transfer.
- How many people took part, and were they randomly assigned? Small, loosely run studies produce big results that do not hold up.
- 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? That alone does not rule a study out. But when a company funds a trial of its own product, the study deserves a closer read.