Background

The widely held belief that commercially available computerized brain-training programs improve general cognitive function in the wider population lacks empirical support.

Objective

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.

Design

Six-week online study with 11,430 participants (Age: 18-60). Participants were randomly assigned to one of the two experimental groups or to the control group.

Method

Four tests that are sensitive to changes in cognitive function in health and disease were used for baseline measures: baseline measures of reasoning, verbal short-term memory (VSTM), spatial working memory (SWM) and paired-associates learning (PAL).

The participants practiced six training tasks for a minimum of 10 min a day, three times a week. In experimental group 1, the six training tasks emphasized reasoning, planning and problem-solving abilities. In experimental group 2, a broader range of cognitive functions was trained using tests of short- term memory, attention, visuospatial processing and mathematics similar to those commonly found in commercially available brain-training devices. The difficulty of the training tasks increased as the participants improved to continuously challenge their cognitive performance and maximize any benefits of training. The control group did not formally practice any specific cognitive tasks during their ‘training’ sessions, but answered obscure questions from six different categories using any available online resource. At six weeks, the tests taken for the baseline measurement were repeated to be compared.

Result

When the three groups were compared directly, effect sizes across all four tests were very small. The improvement on the tests that were actually trained was convincing across all tasks for both experimental groups and the control group. In all three groups, whether these improvements reflected the simple effects of task repetition, the adoption of new task strategies, or a combination of the two is unclear, but whatever the process effecting change, it did not generalize to the untrained, but closely cognitive related, four tests.

Limitations

1. It is unlikely that the four tests were insensitive to the generalized effects, because these tests were chosen for their known sensitivity to small changes in cognitive function.

2. The possibility that a more extensive training regime may have produced an effect cannot be excluded.

3. It cannot be excluded that more focused approaches, such as face-to-face cognitive training, may be beneficial in some circumstances.