The eight
functions
Beyond the four letters, each personality type runs on a set of mental tools called cognitive functions. This is where the real picture starts to emerge.
The Myers-Briggs letters are a simplified map. Cognitive functions are what sits underneath them — the actual mental processes that shape how you take in information and make decisions.
There are eight functions in total. Four deal with perception — how you gather and process information. Four deal with judgement — how you evaluate and decide. Each function comes in two flavours: introverted (directed inward, toward your inner world) and extraverted (directed outward, toward the world around you).
Every type uses all eight, but four are primary. They run in a set order called a function stack — dominant, auxiliary, tertiary and inferior. Take the test to see yours.
Take the test to find out which functions you lead with and how your personal stack shapes the way you think.
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