Brain training aims to enhance cognitive function through repetitive practice, and is analogous to enhancing physical strength or fitness through exercise. It is often administered through the regular use of computerised tests. This has commercial appeal to both consumers and healthcare practitioners, and while programs such as lumosity have developed into a lucrative industry, claims concerning the impact and duration of such brain training largely unsubstantiated 
The central question is not whether performance on cognitive tests can be improved by training, but rather, whether those benefits transfer to other untrained tasks or lead to any general improvement in the level of cognitive functioning. Studies have shown that although improvements are observed in specific cognitive tasks that were trained, no evidence was found for transfer effects to untrained tasks, even when those tasks were cognitively closely related.