1. I doubt the speed intelligence is a kind of ability. Using smart strategies is not a kind of intelligence but skills learned by rote.
2. The simple addition question example in p.24 is not convincing. From experience, everyone always learn the same question solve skill from class. It is questionable that many people used different approach to solve the item. For more complex question, the different skills are not easy to be explained in the mental process.
3. It is assumed that the fast responses are based on more automatic direct-link mediated processing. Can it be a cheat behavior instead of speed intelligence?
4. I did not understand why only the within-item split method is valid on the results on the abilities in study 2? The split method in study 2 is different from study 1?