Human beings have two modes of thought:
System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control. It is fast, instinctive, and emotional.
System 2 allocates attention to the effortful mental activities that demand it, including complex computations. The operations of System 2 are often associated with the subjective experience of agency, choice, and concentration. It is slower, more deliberative, and logical.
Kahneman, Daniel. Thinking, Fast and Slow (pp. 20-21). Farrar, Straus and Giroux. Kindle Edition.