According to Frederick, there are two general types of cognitive activity. The first is executed quickly without reflection, the latter requires conscious thought and effort. These are labelled "system 1" and "system 2" respectively. The Cognitive Reflection Test consists of three questions that each have an obvious response that activates system 1, but which is incorrect. The correct response requires the activation of system 2. However, in order for system two to be activated, a person must note that their first answer is incorrect, which requires them to reflect upon their own cognition.