The brain-training industry sells a clean story: practise the games, get smarter. The uncomfortable finding that keeps recurring is far narrower — people mostly get better at the trained task, and that improvement travels poorly to anything else. If you want to be honest with yourself about improvement, start by separating three different things.
Three things that look identical on a score sheet
- Test familiarity: you have seen this kind of question before and lost less time working out what it wants.
- State: you slept, you are not stressed, you were not interrupted, you cared about doing well.
- Underlying capability: the thing everyone actually means, and the slowest of the three to shift.
Retake almost any reasoning test and your score usually rises. That rise is mostly the first two. It is real in the sense that the number changed; it is not evidence of the third.
What is worth your attention
- Sleep. Short sleep degrades attention and working memory quickly and reliably, and no training programme compensates for it.
- Physical activity and general health — unglamorous, and better supported than most products sold on the promise.
- Deep learning in something real: a language, an instrument, mathematics, a craft. You become genuinely more capable in that domain, which is worth more than an abstract score.
- Test conditions, if a score matters to you: one sitting, no interruptions, not at 2am.
Telling a real change from noise
This is where a confidence interval earns its keep. If your first result was 104-118 and your second is 108-122, nothing has been demonstrated — the ranges overlap almost completely, and the difference sits comfortably inside measurement error. A change only starts to be interesting when ranges barely overlap, it holds across several attempts, and it shows up in a specific domain rather than drifting everywhere at once.
Which is also the case against chasing your own score. Retake often enough and you will nudge the number upward through familiarity while learning nothing about yourself. Your first attempt, taken properly, is usually the most informative one you will ever have.