Anxiety
The philosopher Søren Kierkegaard, in "The Concept of Anxiety" (1844), described anxiety or dread associated with the "dizziness of freedom" and suggested the possibility for positive resolution of anxiety through the self-conscious exercise of responsibility and choosing. In "Art and Artist" (1932), the psychologist Otto Rank wrote that the psychological trauma of birth was the pre-eminent human symbol of existential anxiety and encompasses the creative person's simultaneous fear of – and desire for – separation, individuation, and differentiation.
Brain training
Cogmed was founded in 2001, Posit Science in 2002, and "Brain Age" was first released in 2005, all capitalizing on the growing interest within the public in neuroscience, along with heightened worries by parents about ADHD and other learning disabilities in their children, and concern about their own cognitive health as they aged.