The field of ‘brain training’ – and the excitement surrounding it – is growing rapidly. There is much promise in the idea that training people via memory games and similar exercises can improve overall cognitive function. But this promise has yet to be truly substantiated by research conducted so far. The most convincing studies have shown training gains when it comes to very specific sorts of tasks, but it is unclear whether such improvements will carry over into real-world tasks outside of the lab. Investigations into the effects of ‘brain training’ also suffer from weaknesses common in other kinds of research. The studies claiming to show the greatest effects tend to test smaller numbers of participants without a control group that could guard against the placebo effect.