You're right. The amount of "exercises" that have proven to have some degree of transfer are very limited (n-back being the most typical not the only one). It's

You're right. The amount of "exercises" that have proven to have some degree of transfer are very limited (n-back being the most typical not the only one). It's not only a problem of Lumosity et al, it's a problem on researchers too. There's an alarming amount of papers that are really bad, both methodologically and in terms of the type of tasks and training duration. No wonder the brain training industry gets bashed every now and then when a new study debunks most of the allegedly benefits. So we have a group of folks that don't understand what they are doing and are publishing bad papers, and another group of folks that read those papers without fully understanding what is going on under the hood and create a "brain training" app. The fine on Lumosity by FTC was fair and expected.