Tiger Edition Level 2
Tiger Edition Level 2 Books introduce negative signs into the 3 style, 4 discipline mix of the Level 1 Tiger Books.
Introducing a positive or negative means the brain can no longer operate in the automation comfort zone achieved in the Level 1 books, and thus the cogntiive load is increased considerably in the early exercises of the book.
In time, the brain will develop the ability to automate the negative sign too, signifying that the 'pipe' which is carrying the information between the left and right sides of the brain and coordinating working memory with executive function is expanding and becoming capable of increasingly complex tasks. For more information on the neuroscience, click here. Increasing this capacity is thought to play a key role in problem solving.