System 1 2 or Effortful System or "logical decisions", is the system dealing with complex thinking. It can follow rules, compare objects on several attributes, and make deliberate choices between options<ref>Khanman D., 2011, Thinking fast, Thinking slow p. 36</ref>.

It is part of [http://en.wikipedia.org/wiki/Dual_process_theory two systems of decision making], the first is the automatic-system([[System 1|system 1]]) which decide fast by intuition and the second is the ECS which produce reasoning.The term system 1 and system 2 was given by Stanovich and West<ref>Stanovich KE, West RF., Individual differences in reasoning: implications for the rationality debate? Behav Brain Sci. 2000 Oct;23(5):645-65; discussion 665-726.</ref>. People tend to use system 2 for material purchases, while using system 1 for experiential purchasing<ref>[http://www.acrwebsite.org/volumes/v43/acr_vol43_1019280.pdf Gallo, Iñigo, et al. "The Heart and the Head: On Choosing Experiences Intuitively and Possessions Deliberatively." Journal of Behavioral Decision Making (2016).]‏</ref>.