Luminosity

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Cost:  Free

UDL guideline 8.4 - Provide options for sustaining effort and persistence:  Increase mastery-oriented feedback.  This app meets the guideline by providing feedback about effort level, improvement, performance, modeling in a timely and consistent manner.  After the user has completed the "day's training," the program provides a graph of performance scores and improvement.  There are also information-based recommendations on how to improve future scores.  For example, strategies that determine which distractions can be eliminated during a game to achieve a better score.
General Critique
Luminosity advertises that neuroscience research is the basis for this program.  Be aware that the free app offers five-ten games which are varied throughout the week.  To gain access to the rest of the games and even more performance feedback, a subscription is needed.