Introduction

Some answers arrive with little effort. You recognize a familiar word, notice that a sentence sounds odd, or follow a well-practiced route. Other activities require you to hold several possibilities in mind and work through them deliberately.
These differences are often described as automatic and controlled processing. Automatic processing requires relatively little deliberate attention in a familiar task. Controlled processing involves more intentional effort to guide what you are doing.
The distinction is useful, but it should not become a story about two separate people inside your head. Real activities combine several processes. Fast thinking can be accurate, and careful thinking can still go wrong.