“This was a eureka moment: I realized that the tasks we had chosen for study were exceptionally effortful. An image came to mind: mental life – today I would speak of the life of System 2 – is normally conducted at the pace of a comfortable walk, sometimes interrupted by episodes of jogging and on rare occasions by a frantic sprint. The Add-1 and Add-3 exercises are sprints, and casual chatting is a stroll.”
