Computer implemented training exercises present stimuli to a user and receive responses by the user to the stimuli. The stimuli are specifically selected to challenge and improve a cognitive ability of the user, e.g., the ability to perceive and understand spoken language. As a result, the stimuli cannot be changed or adapted to motivate the user through entertainment. Motivation is therefore provided by periodic reward animations which include persistent plots and characters. Progress indicators represent progress toward reward animations and represent such progression with smooth, entertaining progress animations. Randomly appearing animations and variations in rewards and immediate feedback add to the surprise and curiosity of the user and motivate further correct responses to see further random animations and variations. Progress indicators also represent a relation between the number of steps taking toward completion of a task and a maximum number of steps which should be needed to complete the task. Context is changed at achievement milestones to indicate progress to the user.