An answer search isn't so much a brain teaser as it is an exercise in research. Brain teasers are riddles, puzzles or games that require logic and lateral and creative thinking to solve.
One of the earliest known enthusiasts of brain teasers was the Greek mathematician Archimedes, who used to devise problems for his contemporaries to solve. Nowadays, different types of games and problems are used as brain teasers. There are applications and programs, such as Lumosity, that claim to help a person's focus, attention and memory through games, but the effectiveness of such programs is a highly contentious subject among psychologists and neuroscientists.